xref: /libCEED/backends/cuda-ref/ceed-cuda-ref-operator.c (revision 4b3e95d5da7d4d1a3e8f0acb9d6f6cc36918381b)
1 // Copyright (c) 2017-2024, Lawrence Livermore National Security, LLC and other CEED contributors.
2 // All Rights Reserved. See the top-level LICENSE and NOTICE files for details.
3 //
4 // SPDX-License-Identifier: BSD-2-Clause
5 //
6 // This file is part of CEED:  http://github.com/ceed
7 
8 #include <ceed.h>
9 #include <ceed/backend.h>
10 #include <ceed/jit-tools.h>
11 #include <assert.h>
12 #include <cuda.h>
13 #include <cuda_runtime.h>
14 #include <stdbool.h>
15 #include <string.h>
16 
17 #include "../cuda/ceed-cuda-common.h"
18 #include "../cuda/ceed-cuda-compile.h"
19 #include "ceed-cuda-ref.h"
20 
21 //------------------------------------------------------------------------------
22 // Destroy operator
23 //------------------------------------------------------------------------------
24 static int CeedOperatorDestroy_Cuda(CeedOperator op) {
25   CeedOperator_Cuda *impl;
26 
27   CeedCallBackend(CeedOperatorGetData(op, &impl));
28 
29   // Apply data
30   CeedCallBackend(CeedFree(&impl->skip_rstr_in));
31   for (CeedInt i = 0; i < impl->num_inputs + impl->num_outputs; i++) {
32     CeedCallBackend(CeedVectorDestroy(&impl->e_vecs[i]));
33   }
34   CeedCallBackend(CeedFree(&impl->e_vecs));
35   CeedCallBackend(CeedFree(&impl->input_states));
36 
37   for (CeedInt i = 0; i < impl->num_inputs; i++) {
38     CeedCallBackend(CeedVectorDestroy(&impl->q_vecs_in[i]));
39   }
40   CeedCallBackend(CeedFree(&impl->q_vecs_in));
41 
42   for (CeedInt i = 0; i < impl->num_outputs; i++) {
43     CeedCallBackend(CeedVectorDestroy(&impl->q_vecs_out[i]));
44   }
45   CeedCallBackend(CeedFree(&impl->q_vecs_out));
46   CeedCallBackend(CeedVectorDestroy(&impl->point_coords_elem));
47 
48   // QFunction assembly data
49   for (CeedInt i = 0; i < impl->num_active_in; i++) {
50     CeedCallBackend(CeedVectorDestroy(&impl->qf_active_in[i]));
51   }
52   CeedCallBackend(CeedFree(&impl->qf_active_in));
53 
54   // Diag data
55   if (impl->diag) {
56     Ceed ceed;
57 
58     CeedCallBackend(CeedOperatorGetCeed(op, &ceed));
59     if (impl->diag->module) {
60       CeedCallCuda(ceed, cuModuleUnload(impl->diag->module));
61     }
62     if (impl->diag->module_point_block) {
63       CeedCallCuda(ceed, cuModuleUnload(impl->diag->module_point_block));
64     }
65     CeedCallCuda(ceed, cudaFree(impl->diag->d_eval_modes_in));
66     CeedCallCuda(ceed, cudaFree(impl->diag->d_eval_modes_out));
67     CeedCallCuda(ceed, cudaFree(impl->diag->d_identity));
68     CeedCallCuda(ceed, cudaFree(impl->diag->d_interp_in));
69     CeedCallCuda(ceed, cudaFree(impl->diag->d_interp_out));
70     CeedCallCuda(ceed, cudaFree(impl->diag->d_grad_in));
71     CeedCallCuda(ceed, cudaFree(impl->diag->d_grad_out));
72     CeedCallCuda(ceed, cudaFree(impl->diag->d_div_in));
73     CeedCallCuda(ceed, cudaFree(impl->diag->d_div_out));
74     CeedCallCuda(ceed, cudaFree(impl->diag->d_curl_in));
75     CeedCallCuda(ceed, cudaFree(impl->diag->d_curl_out));
76     CeedCallBackend(CeedElemRestrictionDestroy(&impl->diag->diag_rstr));
77     CeedCallBackend(CeedElemRestrictionDestroy(&impl->diag->point_block_diag_rstr));
78     CeedCallBackend(CeedVectorDestroy(&impl->diag->elem_diag));
79     CeedCallBackend(CeedVectorDestroy(&impl->diag->point_block_elem_diag));
80   }
81   CeedCallBackend(CeedFree(&impl->diag));
82 
83   if (impl->asmb) {
84     Ceed ceed;
85 
86     CeedCallBackend(CeedOperatorGetCeed(op, &ceed));
87     CeedCallCuda(ceed, cuModuleUnload(impl->asmb->module));
88     CeedCallCuda(ceed, cudaFree(impl->asmb->d_B_in));
89     CeedCallCuda(ceed, cudaFree(impl->asmb->d_B_out));
90   }
91   CeedCallBackend(CeedFree(&impl->asmb));
92 
93   CeedCallBackend(CeedFree(&impl));
94   return CEED_ERROR_SUCCESS;
95 }
96 
97 //------------------------------------------------------------------------------
98 // Setup infields or outfields
99 //------------------------------------------------------------------------------
100 static int CeedOperatorSetupFields_Cuda(CeedQFunction qf, CeedOperator op, bool is_input, bool is_at_points, bool *skip_rstr, CeedVector *e_vecs,
101                                         CeedVector *q_vecs, CeedInt start_e, CeedInt num_fields, CeedInt Q, CeedInt num_elem) {
102   Ceed                ceed;
103   CeedQFunctionField *qf_fields;
104   CeedOperatorField  *op_fields;
105 
106   CeedCallBackend(CeedOperatorGetCeed(op, &ceed));
107   if (is_input) {
108     CeedCallBackend(CeedOperatorGetFields(op, NULL, &op_fields, NULL, NULL));
109     CeedCallBackend(CeedQFunctionGetFields(qf, NULL, &qf_fields, NULL, NULL));
110   } else {
111     CeedCallBackend(CeedOperatorGetFields(op, NULL, NULL, NULL, &op_fields));
112     CeedCallBackend(CeedQFunctionGetFields(qf, NULL, NULL, NULL, &qf_fields));
113   }
114 
115   // Loop over fields
116   for (CeedInt i = 0; i < num_fields; i++) {
117     bool         is_strided = false, skip_restriction = false;
118     CeedSize     q_size;
119     CeedInt      size;
120     CeedEvalMode eval_mode;
121     CeedBasis    basis;
122 
123     CeedCallBackend(CeedQFunctionFieldGetEvalMode(qf_fields[i], &eval_mode));
124     if (eval_mode != CEED_EVAL_WEIGHT) {
125       CeedElemRestriction elem_rstr;
126 
127       // Check whether this field can skip the element restriction:
128       // Must be passive input, with eval_mode NONE, and have a strided restriction with CEED_STRIDES_BACKEND.
129       CeedCallBackend(CeedOperatorFieldGetElemRestriction(op_fields[i], &elem_rstr));
130 
131       // First, check whether the field is input or output:
132       if (is_input) {
133         CeedVector vec;
134 
135         // Check for passive input
136         CeedCallBackend(CeedOperatorFieldGetVector(op_fields[i], &vec));
137         if (vec != CEED_VECTOR_ACTIVE) {
138           // Check eval_mode
139           if (eval_mode == CEED_EVAL_NONE) {
140             // Check for strided restriction
141             CeedCallBackend(CeedElemRestrictionIsStrided(elem_rstr, &is_strided));
142             if (is_strided) {
143               // Check if vector is already in preferred backend ordering
144               CeedCallBackend(CeedElemRestrictionHasBackendStrides(elem_rstr, &skip_restriction));
145             }
146           }
147         }
148       }
149       if (skip_restriction) {
150         // We do not need an E-Vector, but will use the input field vector's data directly in the operator application.
151         e_vecs[i + start_e] = NULL;
152       } else {
153         CeedCallBackend(CeedElemRestrictionCreateVector(elem_rstr, NULL, &e_vecs[i + start_e]));
154       }
155     }
156 
157     switch (eval_mode) {
158       case CEED_EVAL_NONE:
159         CeedCallBackend(CeedQFunctionFieldGetSize(qf_fields[i], &size));
160         q_size = (CeedSize)num_elem * Q * size;
161         CeedCallBackend(CeedVectorCreate(ceed, q_size, &q_vecs[i]));
162         break;
163       case CEED_EVAL_INTERP:
164       case CEED_EVAL_GRAD:
165       case CEED_EVAL_DIV:
166       case CEED_EVAL_CURL:
167         CeedCallBackend(CeedQFunctionFieldGetSize(qf_fields[i], &size));
168         q_size = (CeedSize)num_elem * Q * size;
169         CeedCallBackend(CeedVectorCreate(ceed, q_size, &q_vecs[i]));
170         break;
171       case CEED_EVAL_WEIGHT:  // Only on input fields
172         CeedCallBackend(CeedOperatorFieldGetBasis(op_fields[i], &basis));
173         q_size = (CeedSize)num_elem * Q;
174         CeedCallBackend(CeedVectorCreate(ceed, q_size, &q_vecs[i]));
175         if (is_at_points) {
176           CeedInt num_points[num_elem];
177 
178           for (CeedInt i = 0; i < num_elem; i++) num_points[i] = Q;
179           CeedCallBackend(
180               CeedBasisApplyAtPoints(basis, num_elem, num_points, CEED_NOTRANSPOSE, CEED_EVAL_WEIGHT, CEED_VECTOR_NONE, CEED_VECTOR_NONE, q_vecs[i]));
181         } else {
182           CeedCallBackend(CeedBasisApply(basis, num_elem, CEED_NOTRANSPOSE, CEED_EVAL_WEIGHT, CEED_VECTOR_NONE, q_vecs[i]));
183         }
184         break;
185     }
186   }
187   // Drop duplicate input restrictions
188   if (is_input) {
189     for (CeedInt i = 0; i < num_fields; i++) {
190       CeedVector          vec_i;
191       CeedElemRestriction rstr_i;
192 
193       CeedCallBackend(CeedOperatorFieldGetVector(op_fields[i], &vec_i));
194       CeedCallBackend(CeedOperatorFieldGetElemRestriction(op_fields[i], &rstr_i));
195       for (CeedInt j = i + 1; j < num_fields; j++) {
196         CeedVector          vec_j;
197         CeedElemRestriction rstr_j;
198 
199         CeedCallBackend(CeedOperatorFieldGetVector(op_fields[j], &vec_j));
200         CeedCallBackend(CeedOperatorFieldGetElemRestriction(op_fields[j], &rstr_j));
201         if (vec_i == vec_j && rstr_i == rstr_j) {
202           CeedCallBackend(CeedVectorReferenceCopy(e_vecs[i], &e_vecs[j]));
203           skip_rstr[j] = true;
204         }
205       }
206     }
207   }
208   return CEED_ERROR_SUCCESS;
209 }
210 
211 //------------------------------------------------------------------------------
212 // CeedOperator needs to connect all the named fields (be they active or passive) to the named inputs and outputs of its CeedQFunction.
213 //------------------------------------------------------------------------------
214 static int CeedOperatorSetup_Cuda(CeedOperator op) {
215   Ceed                ceed;
216   bool                is_setup_done;
217   CeedInt             Q, num_elem, num_input_fields, num_output_fields;
218   CeedQFunctionField *qf_input_fields, *qf_output_fields;
219   CeedQFunction       qf;
220   CeedOperatorField  *op_input_fields, *op_output_fields;
221   CeedOperator_Cuda  *impl;
222 
223   CeedCallBackend(CeedOperatorIsSetupDone(op, &is_setup_done));
224   if (is_setup_done) return CEED_ERROR_SUCCESS;
225 
226   CeedCallBackend(CeedOperatorGetCeed(op, &ceed));
227   CeedCallBackend(CeedOperatorGetData(op, &impl));
228   CeedCallBackend(CeedOperatorGetQFunction(op, &qf));
229   CeedCallBackend(CeedOperatorGetNumQuadraturePoints(op, &Q));
230   CeedCallBackend(CeedOperatorGetNumElements(op, &num_elem));
231   CeedCallBackend(CeedOperatorGetFields(op, &num_input_fields, &op_input_fields, &num_output_fields, &op_output_fields));
232   CeedCallBackend(CeedQFunctionGetFields(qf, NULL, &qf_input_fields, NULL, &qf_output_fields));
233 
234   // Allocate
235   CeedCallBackend(CeedCalloc(num_input_fields + num_output_fields, &impl->e_vecs));
236   CeedCallBackend(CeedCalloc(CEED_FIELD_MAX, &impl->skip_rstr_in));
237   CeedCallBackend(CeedCalloc(CEED_FIELD_MAX, &impl->input_states));
238   CeedCallBackend(CeedCalloc(CEED_FIELD_MAX, &impl->q_vecs_in));
239   CeedCallBackend(CeedCalloc(CEED_FIELD_MAX, &impl->q_vecs_out));
240   impl->num_inputs  = num_input_fields;
241   impl->num_outputs = num_output_fields;
242 
243   // Set up infield and outfield e_vecs and q_vecs
244   // Infields
245   CeedCallBackend(
246       CeedOperatorSetupFields_Cuda(qf, op, true, false, impl->skip_rstr_in, impl->e_vecs, impl->q_vecs_in, 0, num_input_fields, Q, num_elem));
247   // Outfields
248   CeedCallBackend(
249       CeedOperatorSetupFields_Cuda(qf, op, false, false, NULL, impl->e_vecs, impl->q_vecs_out, num_input_fields, num_output_fields, Q, num_elem));
250 
251   CeedCallBackend(CeedOperatorSetSetupDone(op));
252   return CEED_ERROR_SUCCESS;
253 }
254 
255 //------------------------------------------------------------------------------
256 // Setup Operator Inputs
257 //------------------------------------------------------------------------------
258 static inline int CeedOperatorSetupInputs_Cuda(CeedInt num_input_fields, CeedQFunctionField *qf_input_fields, CeedOperatorField *op_input_fields,
259                                                CeedVector in_vec, const bool skip_active, CeedScalar *e_data[2 * CEED_FIELD_MAX],
260                                                CeedOperator_Cuda *impl, CeedRequest *request) {
261   for (CeedInt i = 0; i < num_input_fields; i++) {
262     CeedEvalMode        eval_mode;
263     CeedVector          vec;
264     CeedElemRestriction elem_rstr;
265 
266     // Get input vector
267     CeedCallBackend(CeedOperatorFieldGetVector(op_input_fields[i], &vec));
268     if (vec == CEED_VECTOR_ACTIVE) {
269       if (skip_active) continue;
270       else vec = in_vec;
271     }
272 
273     CeedCallBackend(CeedQFunctionFieldGetEvalMode(qf_input_fields[i], &eval_mode));
274     if (eval_mode == CEED_EVAL_WEIGHT) {  // Skip
275     } else {
276       // Get input vector
277       CeedCallBackend(CeedOperatorFieldGetVector(op_input_fields[i], &vec));
278       // Get input element restriction
279       CeedCallBackend(CeedOperatorFieldGetElemRestriction(op_input_fields[i], &elem_rstr));
280       if (vec == CEED_VECTOR_ACTIVE) vec = in_vec;
281       // Restrict, if necessary
282       if (!impl->e_vecs[i]) {
283         // No restriction for this field; read data directly from vec.
284         CeedCallBackend(CeedVectorGetArrayRead(vec, CEED_MEM_DEVICE, (const CeedScalar **)&e_data[i]));
285       } else {
286         uint64_t state;
287 
288         CeedCallBackend(CeedVectorGetState(vec, &state));
289         if (state != impl->input_states[i] && !impl->skip_rstr_in[i]) {
290           CeedCallBackend(CeedElemRestrictionApply(elem_rstr, CEED_NOTRANSPOSE, vec, impl->e_vecs[i], request));
291         }
292         impl->input_states[i] = state;
293         // Get evec
294         CeedCallBackend(CeedVectorGetArrayRead(impl->e_vecs[i], CEED_MEM_DEVICE, (const CeedScalar **)&e_data[i]));
295       }
296     }
297   }
298   return CEED_ERROR_SUCCESS;
299 }
300 
301 //------------------------------------------------------------------------------
302 // Input Basis Action
303 //------------------------------------------------------------------------------
304 static inline int CeedOperatorInputBasis_Cuda(CeedInt num_elem, CeedQFunctionField *qf_input_fields, CeedOperatorField *op_input_fields,
305                                               CeedInt num_input_fields, const bool skip_active, CeedScalar *e_data[2 * CEED_FIELD_MAX],
306                                               CeedOperator_Cuda *impl) {
307   for (CeedInt i = 0; i < num_input_fields; i++) {
308     CeedInt             elem_size, size;
309     CeedEvalMode        eval_mode;
310     CeedElemRestriction elem_rstr;
311     CeedBasis           basis;
312 
313     // Skip active input
314     if (skip_active) {
315       CeedVector vec;
316 
317       CeedCallBackend(CeedOperatorFieldGetVector(op_input_fields[i], &vec));
318       if (vec == CEED_VECTOR_ACTIVE) continue;
319     }
320     // Get elem_size, eval_mode, size
321     CeedCallBackend(CeedOperatorFieldGetElemRestriction(op_input_fields[i], &elem_rstr));
322     CeedCallBackend(CeedElemRestrictionGetElementSize(elem_rstr, &elem_size));
323     CeedCallBackend(CeedQFunctionFieldGetEvalMode(qf_input_fields[i], &eval_mode));
324     CeedCallBackend(CeedQFunctionFieldGetSize(qf_input_fields[i], &size));
325     // Basis action
326     switch (eval_mode) {
327       case CEED_EVAL_NONE:
328         CeedCallBackend(CeedVectorSetArray(impl->q_vecs_in[i], CEED_MEM_DEVICE, CEED_USE_POINTER, e_data[i]));
329         break;
330       case CEED_EVAL_INTERP:
331       case CEED_EVAL_GRAD:
332       case CEED_EVAL_DIV:
333       case CEED_EVAL_CURL:
334         CeedCallBackend(CeedOperatorFieldGetBasis(op_input_fields[i], &basis));
335         CeedCallBackend(CeedBasisApply(basis, num_elem, CEED_NOTRANSPOSE, eval_mode, impl->e_vecs[i], impl->q_vecs_in[i]));
336         break;
337       case CEED_EVAL_WEIGHT:
338         break;  // No action
339     }
340   }
341   return CEED_ERROR_SUCCESS;
342 }
343 
344 //------------------------------------------------------------------------------
345 // Restore Input Vectors
346 //------------------------------------------------------------------------------
347 static inline int CeedOperatorRestoreInputs_Cuda(CeedInt num_input_fields, CeedQFunctionField *qf_input_fields, CeedOperatorField *op_input_fields,
348                                                  const bool skip_active, CeedScalar *e_data[2 * CEED_FIELD_MAX], CeedOperator_Cuda *impl) {
349   for (CeedInt i = 0; i < num_input_fields; i++) {
350     CeedEvalMode eval_mode;
351     CeedVector   vec;
352 
353     // Skip active input
354     if (skip_active) {
355       CeedCallBackend(CeedOperatorFieldGetVector(op_input_fields[i], &vec));
356       if (vec == CEED_VECTOR_ACTIVE) continue;
357     }
358     CeedCallBackend(CeedQFunctionFieldGetEvalMode(qf_input_fields[i], &eval_mode));
359     if (eval_mode == CEED_EVAL_WEIGHT) {  // Skip
360     } else {
361       if (!impl->e_vecs[i]) {  // This was a skip_restriction case
362         CeedCallBackend(CeedOperatorFieldGetVector(op_input_fields[i], &vec));
363         CeedCallBackend(CeedVectorRestoreArrayRead(vec, (const CeedScalar **)&e_data[i]));
364       } else {
365         CeedCallBackend(CeedVectorRestoreArrayRead(impl->e_vecs[i], (const CeedScalar **)&e_data[i]));
366       }
367     }
368   }
369   return CEED_ERROR_SUCCESS;
370 }
371 
372 //------------------------------------------------------------------------------
373 // Apply and add to output
374 //------------------------------------------------------------------------------
375 static int CeedOperatorApplyAdd_Cuda(CeedOperator op, CeedVector in_vec, CeedVector out_vec, CeedRequest *request) {
376   CeedInt             Q, num_elem, elem_size, num_input_fields, num_output_fields, size;
377   CeedScalar         *e_data[2 * CEED_FIELD_MAX] = {NULL};
378   CeedQFunctionField *qf_input_fields, *qf_output_fields;
379   CeedQFunction       qf;
380   CeedOperatorField  *op_input_fields, *op_output_fields;
381   CeedOperator_Cuda  *impl;
382 
383   CeedCallBackend(CeedOperatorGetData(op, &impl));
384   CeedCallBackend(CeedOperatorGetQFunction(op, &qf));
385   CeedCallBackend(CeedOperatorGetNumQuadraturePoints(op, &Q));
386   CeedCallBackend(CeedOperatorGetNumElements(op, &num_elem));
387   CeedCallBackend(CeedOperatorGetFields(op, &num_input_fields, &op_input_fields, &num_output_fields, &op_output_fields));
388   CeedCallBackend(CeedQFunctionGetFields(qf, NULL, &qf_input_fields, NULL, &qf_output_fields));
389 
390   // Setup
391   CeedCallBackend(CeedOperatorSetup_Cuda(op));
392 
393   // Input Evecs and Restriction
394   CeedCallBackend(CeedOperatorSetupInputs_Cuda(num_input_fields, qf_input_fields, op_input_fields, in_vec, false, e_data, impl, request));
395 
396   // Input basis apply if needed
397   CeedCallBackend(CeedOperatorInputBasis_Cuda(num_elem, qf_input_fields, op_input_fields, num_input_fields, false, e_data, impl));
398 
399   // Output pointers, as necessary
400   for (CeedInt i = 0; i < num_output_fields; i++) {
401     CeedEvalMode eval_mode;
402 
403     CeedCallBackend(CeedQFunctionFieldGetEvalMode(qf_output_fields[i], &eval_mode));
404     if (eval_mode == CEED_EVAL_NONE) {
405       // Set the output Q-Vector to use the E-Vector data directly.
406       CeedCallBackend(CeedVectorGetArrayWrite(impl->e_vecs[i + impl->num_inputs], CEED_MEM_DEVICE, &e_data[i + num_input_fields]));
407       CeedCallBackend(CeedVectorSetArray(impl->q_vecs_out[i], CEED_MEM_DEVICE, CEED_USE_POINTER, e_data[i + num_input_fields]));
408     }
409   }
410 
411   // Q function
412   CeedCallBackend(CeedQFunctionApply(qf, num_elem * Q, impl->q_vecs_in, impl->q_vecs_out));
413 
414   // Output basis apply if needed
415   for (CeedInt i = 0; i < num_output_fields; i++) {
416     CeedEvalMode        eval_mode;
417     CeedElemRestriction elem_rstr;
418     CeedBasis           basis;
419 
420     // Get elem_size, eval_mode, size
421     CeedCallBackend(CeedOperatorFieldGetElemRestriction(op_output_fields[i], &elem_rstr));
422     CeedCallBackend(CeedElemRestrictionGetElementSize(elem_rstr, &elem_size));
423     CeedCallBackend(CeedQFunctionFieldGetEvalMode(qf_output_fields[i], &eval_mode));
424     CeedCallBackend(CeedQFunctionFieldGetSize(qf_output_fields[i], &size));
425     // Basis action
426     switch (eval_mode) {
427       case CEED_EVAL_NONE:
428         break;  // No action
429       case CEED_EVAL_INTERP:
430       case CEED_EVAL_GRAD:
431       case CEED_EVAL_DIV:
432       case CEED_EVAL_CURL:
433         CeedCallBackend(CeedOperatorFieldGetBasis(op_output_fields[i], &basis));
434         CeedCallBackend(CeedBasisApply(basis, num_elem, CEED_TRANSPOSE, eval_mode, impl->q_vecs_out[i], impl->e_vecs[i + impl->num_inputs]));
435         break;
436       // LCOV_EXCL_START
437       case CEED_EVAL_WEIGHT: {
438         return CeedError(CeedOperatorReturnCeed(op), CEED_ERROR_BACKEND, "CEED_EVAL_WEIGHT cannot be an output evaluation mode");
439         // LCOV_EXCL_STOP
440       }
441     }
442   }
443 
444   // Output restriction
445   for (CeedInt i = 0; i < num_output_fields; i++) {
446     CeedEvalMode        eval_mode;
447     CeedVector          vec;
448     CeedElemRestriction elem_rstr;
449 
450     // Restore evec
451     CeedCallBackend(CeedQFunctionFieldGetEvalMode(qf_output_fields[i], &eval_mode));
452     if (eval_mode == CEED_EVAL_NONE) {
453       CeedCallBackend(CeedVectorRestoreArray(impl->e_vecs[i + impl->num_inputs], &e_data[i + num_input_fields]));
454     }
455     // Get output vector
456     CeedCallBackend(CeedOperatorFieldGetVector(op_output_fields[i], &vec));
457     // Restrict
458     CeedCallBackend(CeedOperatorFieldGetElemRestriction(op_output_fields[i], &elem_rstr));
459     // Active
460     if (vec == CEED_VECTOR_ACTIVE) vec = out_vec;
461 
462     CeedCallBackend(CeedElemRestrictionApply(elem_rstr, CEED_TRANSPOSE, impl->e_vecs[i + impl->num_inputs], vec, request));
463   }
464 
465   // Restore input arrays
466   CeedCallBackend(CeedOperatorRestoreInputs_Cuda(num_input_fields, qf_input_fields, op_input_fields, false, e_data, impl));
467   return CEED_ERROR_SUCCESS;
468 }
469 
470 //------------------------------------------------------------------------------
471 // CeedOperator needs to connect all the named fields (be they active or passive) to the named inputs and outputs of its CeedQFunction.
472 //------------------------------------------------------------------------------
473 static int CeedOperatorSetupAtPoints_Cuda(CeedOperator op) {
474   Ceed                ceed;
475   bool                is_setup_done;
476   CeedInt             max_num_points = -1, num_elem, num_input_fields, num_output_fields;
477   CeedQFunctionField *qf_input_fields, *qf_output_fields;
478   CeedQFunction       qf;
479   CeedOperatorField  *op_input_fields, *op_output_fields;
480   CeedOperator_Cuda  *impl;
481 
482   CeedCallBackend(CeedOperatorIsSetupDone(op, &is_setup_done));
483   if (is_setup_done) return CEED_ERROR_SUCCESS;
484 
485   CeedCallBackend(CeedOperatorGetCeed(op, &ceed));
486   CeedCallBackend(CeedOperatorGetData(op, &impl));
487   CeedCallBackend(CeedOperatorGetQFunction(op, &qf));
488   CeedCallBackend(CeedOperatorGetNumElements(op, &num_elem));
489   CeedCallBackend(CeedOperatorGetFields(op, &num_input_fields, &op_input_fields, &num_output_fields, &op_output_fields));
490   CeedCallBackend(CeedQFunctionGetFields(qf, NULL, &qf_input_fields, NULL, &qf_output_fields));
491   {
492     CeedElemRestriction elem_rstr = NULL;
493 
494     CeedCallBackend(CeedOperatorAtPointsGetPoints(op, &elem_rstr, NULL));
495     CeedCallBackend(CeedElemRestrictionGetMaxPointsInElement(elem_rstr, &max_num_points));
496   }
497   impl->max_num_points = max_num_points;
498 
499   // Allocate
500   CeedCallBackend(CeedCalloc(num_input_fields + num_output_fields, &impl->e_vecs));
501   CeedCallBackend(CeedCalloc(CEED_FIELD_MAX, &impl->skip_rstr_in));
502   CeedCallBackend(CeedCalloc(CEED_FIELD_MAX, &impl->input_states));
503   CeedCallBackend(CeedCalloc(CEED_FIELD_MAX, &impl->q_vecs_in));
504   CeedCallBackend(CeedCalloc(CEED_FIELD_MAX, &impl->q_vecs_out));
505   impl->num_inputs  = num_input_fields;
506   impl->num_outputs = num_output_fields;
507 
508   // Set up infield and outfield e_vecs and q_vecs
509   // Infields
510   CeedCallBackend(CeedOperatorSetupFields_Cuda(qf, op, true, true, impl->skip_rstr_in, impl->e_vecs, impl->q_vecs_in, 0, num_input_fields,
511                                                max_num_points, num_elem));
512   // Outfields
513   CeedCallBackend(CeedOperatorSetupFields_Cuda(qf, op, false, true, NULL, impl->e_vecs, impl->q_vecs_out, num_input_fields, num_output_fields,
514                                                max_num_points, num_elem));
515 
516   CeedCallBackend(CeedOperatorSetSetupDone(op));
517   return CEED_ERROR_SUCCESS;
518 }
519 
520 //------------------------------------------------------------------------------
521 // Input Basis Action AtPoints
522 //------------------------------------------------------------------------------
523 static inline int CeedOperatorInputBasisAtPoints_Cuda(CeedInt num_elem, const CeedInt *num_points, CeedQFunctionField *qf_input_fields,
524                                                       CeedOperatorField *op_input_fields, CeedInt num_input_fields, const bool skip_active,
525                                                       CeedScalar *e_data[2 * CEED_FIELD_MAX], CeedOperator_Cuda *impl) {
526   for (CeedInt i = 0; i < num_input_fields; i++) {
527     CeedInt             elem_size, size;
528     CeedEvalMode        eval_mode;
529     CeedElemRestriction elem_rstr;
530     CeedBasis           basis;
531 
532     // Skip active input
533     if (skip_active) {
534       CeedVector vec;
535 
536       CeedCallBackend(CeedOperatorFieldGetVector(op_input_fields[i], &vec));
537       if (vec == CEED_VECTOR_ACTIVE) continue;
538     }
539     // Get elem_size, eval_mode, size
540     CeedCallBackend(CeedOperatorFieldGetElemRestriction(op_input_fields[i], &elem_rstr));
541     CeedCallBackend(CeedElemRestrictionGetElementSize(elem_rstr, &elem_size));
542     CeedCallBackend(CeedQFunctionFieldGetEvalMode(qf_input_fields[i], &eval_mode));
543     CeedCallBackend(CeedQFunctionFieldGetSize(qf_input_fields[i], &size));
544     // Basis action
545     switch (eval_mode) {
546       case CEED_EVAL_NONE:
547         CeedCallBackend(CeedVectorSetArray(impl->q_vecs_in[i], CEED_MEM_DEVICE, CEED_USE_POINTER, e_data[i]));
548         break;
549       case CEED_EVAL_INTERP:
550       case CEED_EVAL_GRAD:
551       case CEED_EVAL_DIV:
552       case CEED_EVAL_CURL:
553         CeedCallBackend(CeedOperatorFieldGetBasis(op_input_fields[i], &basis));
554         CeedCallBackend(CeedBasisApplyAtPoints(basis, num_elem, num_points, CEED_NOTRANSPOSE, eval_mode, impl->point_coords_elem, impl->e_vecs[i],
555                                                impl->q_vecs_in[i]));
556         break;
557       case CEED_EVAL_WEIGHT:
558         break;  // No action
559     }
560   }
561   return CEED_ERROR_SUCCESS;
562 }
563 
564 //------------------------------------------------------------------------------
565 // Apply and add to output AtPoints
566 //------------------------------------------------------------------------------
567 static int CeedOperatorApplyAddAtPoints_Cuda(CeedOperator op, CeedVector in_vec, CeedVector out_vec, CeedRequest *request) {
568   CeedInt             max_num_points, num_elem, elem_size, num_input_fields, num_output_fields, size;
569   CeedScalar         *e_data[2 * CEED_FIELD_MAX] = {NULL};
570   CeedQFunctionField *qf_input_fields, *qf_output_fields;
571   CeedQFunction       qf;
572   CeedOperatorField  *op_input_fields, *op_output_fields;
573   CeedOperator_Cuda  *impl;
574 
575   CeedCallBackend(CeedOperatorGetData(op, &impl));
576   CeedCallBackend(CeedOperatorGetQFunction(op, &qf));
577   CeedCallBackend(CeedOperatorGetNumElements(op, &num_elem));
578   CeedCallBackend(CeedOperatorGetFields(op, &num_input_fields, &op_input_fields, &num_output_fields, &op_output_fields));
579   CeedCallBackend(CeedQFunctionGetFields(qf, NULL, &qf_input_fields, NULL, &qf_output_fields));
580   CeedInt num_points[num_elem];
581 
582   // Setup
583   CeedCallBackend(CeedOperatorSetupAtPoints_Cuda(op));
584   max_num_points = impl->max_num_points;
585   for (CeedInt i = 0; i < num_elem; i++) num_points[i] = max_num_points;
586 
587   // Input Evecs and Restriction
588   CeedCallBackend(CeedOperatorSetupInputs_Cuda(num_input_fields, qf_input_fields, op_input_fields, in_vec, false, e_data, impl, request));
589 
590   // Get point coordinates
591   if (!impl->point_coords_elem) {
592     CeedVector          point_coords = NULL;
593     CeedElemRestriction rstr_points  = NULL;
594 
595     CeedCallBackend(CeedOperatorAtPointsGetPoints(op, &rstr_points, &point_coords));
596     CeedCallBackend(CeedElemRestrictionCreateVector(rstr_points, NULL, &impl->point_coords_elem));
597     CeedCallBackend(CeedElemRestrictionApply(rstr_points, CEED_NOTRANSPOSE, point_coords, impl->point_coords_elem, request));
598   }
599 
600   // Input basis apply if needed
601   CeedCallBackend(CeedOperatorInputBasisAtPoints_Cuda(num_elem, num_points, qf_input_fields, op_input_fields, num_input_fields, false, e_data, impl));
602 
603   // Output pointers, as necessary
604   for (CeedInt i = 0; i < num_output_fields; i++) {
605     CeedEvalMode eval_mode;
606 
607     CeedCallBackend(CeedQFunctionFieldGetEvalMode(qf_output_fields[i], &eval_mode));
608     if (eval_mode == CEED_EVAL_NONE) {
609       // Set the output Q-Vector to use the E-Vector data directly.
610       CeedCallBackend(CeedVectorGetArrayWrite(impl->e_vecs[i + impl->num_inputs], CEED_MEM_DEVICE, &e_data[i + num_input_fields]));
611       CeedCallBackend(CeedVectorSetArray(impl->q_vecs_out[i], CEED_MEM_DEVICE, CEED_USE_POINTER, e_data[i + num_input_fields]));
612     }
613   }
614 
615   // Q function
616   CeedCallBackend(CeedQFunctionApply(qf, num_elem * max_num_points, impl->q_vecs_in, impl->q_vecs_out));
617 
618   // Output basis apply if needed
619   for (CeedInt i = 0; i < num_output_fields; i++) {
620     CeedEvalMode        eval_mode;
621     CeedElemRestriction elem_rstr;
622     CeedBasis           basis;
623 
624     // Get elem_size, eval_mode, size
625     CeedCallBackend(CeedOperatorFieldGetElemRestriction(op_output_fields[i], &elem_rstr));
626     CeedCallBackend(CeedElemRestrictionGetElementSize(elem_rstr, &elem_size));
627     CeedCallBackend(CeedQFunctionFieldGetEvalMode(qf_output_fields[i], &eval_mode));
628     CeedCallBackend(CeedQFunctionFieldGetSize(qf_output_fields[i], &size));
629     // Basis action
630     switch (eval_mode) {
631       case CEED_EVAL_NONE:
632         break;  // No action
633       case CEED_EVAL_INTERP:
634       case CEED_EVAL_GRAD:
635       case CEED_EVAL_DIV:
636       case CEED_EVAL_CURL:
637         CeedCallBackend(CeedOperatorFieldGetBasis(op_output_fields[i], &basis));
638         CeedCallBackend(CeedBasisApplyAtPoints(basis, num_elem, num_points, CEED_TRANSPOSE, eval_mode, impl->point_coords_elem, impl->q_vecs_out[i],
639                                                impl->e_vecs[i + impl->num_inputs]));
640         break;
641       // LCOV_EXCL_START
642       case CEED_EVAL_WEIGHT: {
643         return CeedError(CeedOperatorReturnCeed(op), CEED_ERROR_BACKEND, "CEED_EVAL_WEIGHT cannot be an output evaluation mode");
644         // LCOV_EXCL_STOP
645       }
646     }
647   }
648 
649   // Output restriction
650   for (CeedInt i = 0; i < num_output_fields; i++) {
651     CeedEvalMode        eval_mode;
652     CeedVector          vec;
653     CeedElemRestriction elem_rstr;
654 
655     // Restore evec
656     CeedCallBackend(CeedQFunctionFieldGetEvalMode(qf_output_fields[i], &eval_mode));
657     if (eval_mode == CEED_EVAL_NONE) {
658       CeedCallBackend(CeedVectorRestoreArray(impl->e_vecs[i + impl->num_inputs], &e_data[i + num_input_fields]));
659     }
660     // Get output vector
661     CeedCallBackend(CeedOperatorFieldGetVector(op_output_fields[i], &vec));
662     // Restrict
663     CeedCallBackend(CeedOperatorFieldGetElemRestriction(op_output_fields[i], &elem_rstr));
664     // Active
665     if (vec == CEED_VECTOR_ACTIVE) vec = out_vec;
666 
667     CeedCallBackend(CeedElemRestrictionApply(elem_rstr, CEED_TRANSPOSE, impl->e_vecs[i + impl->num_inputs], vec, request));
668   }
669 
670   // Restore input arrays
671   CeedCallBackend(CeedOperatorRestoreInputs_Cuda(num_input_fields, qf_input_fields, op_input_fields, false, e_data, impl));
672   return CEED_ERROR_SUCCESS;
673 }
674 
675 //------------------------------------------------------------------------------
676 // Linear QFunction Assembly Core
677 //------------------------------------------------------------------------------
678 static inline int CeedOperatorLinearAssembleQFunctionCore_Cuda(CeedOperator op, bool build_objects, CeedVector *assembled, CeedElemRestriction *rstr,
679                                                                CeedRequest *request) {
680   Ceed                ceed, ceed_parent;
681   CeedInt             num_active_in, num_active_out, Q, num_elem, num_input_fields, num_output_fields, size;
682   CeedScalar         *assembled_array, *e_data[2 * CEED_FIELD_MAX] = {NULL};
683   CeedVector         *active_inputs;
684   CeedQFunctionField *qf_input_fields, *qf_output_fields;
685   CeedQFunction       qf;
686   CeedOperatorField  *op_input_fields, *op_output_fields;
687   CeedOperator_Cuda  *impl;
688 
689   CeedCallBackend(CeedOperatorGetCeed(op, &ceed));
690   CeedCallBackend(CeedOperatorGetFallbackParentCeed(op, &ceed_parent));
691   CeedCallBackend(CeedOperatorGetData(op, &impl));
692   CeedCallBackend(CeedOperatorGetNumQuadraturePoints(op, &Q));
693   CeedCallBackend(CeedOperatorGetNumElements(op, &num_elem));
694   CeedCallBackend(CeedOperatorGetQFunction(op, &qf));
695   CeedCallBackend(CeedQFunctionGetFields(qf, NULL, &qf_input_fields, NULL, &qf_output_fields));
696   CeedCallBackend(CeedOperatorGetFields(op, &num_input_fields, &op_input_fields, &num_output_fields, &op_output_fields));
697   active_inputs = impl->qf_active_in;
698   num_active_in = impl->num_active_in, num_active_out = impl->num_active_out;
699 
700   // Setup
701   CeedCallBackend(CeedOperatorSetup_Cuda(op));
702 
703   // Input Evecs and Restriction
704   CeedCallBackend(CeedOperatorSetupInputs_Cuda(num_input_fields, qf_input_fields, op_input_fields, NULL, true, e_data, impl, request));
705 
706   // Count number of active input fields
707   if (!num_active_in) {
708     for (CeedInt i = 0; i < num_input_fields; i++) {
709       CeedScalar *q_vec_array;
710       CeedVector  vec;
711 
712       // Get input vector
713       CeedCallBackend(CeedOperatorFieldGetVector(op_input_fields[i], &vec));
714       // Check if active input
715       if (vec == CEED_VECTOR_ACTIVE) {
716         CeedCallBackend(CeedQFunctionFieldGetSize(qf_input_fields[i], &size));
717         CeedCallBackend(CeedVectorSetValue(impl->q_vecs_in[i], 0.0));
718         CeedCallBackend(CeedVectorGetArray(impl->q_vecs_in[i], CEED_MEM_DEVICE, &q_vec_array));
719         CeedCallBackend(CeedRealloc(num_active_in + size, &active_inputs));
720         for (CeedInt field = 0; field < size; field++) {
721           CeedSize q_size = (CeedSize)Q * num_elem;
722 
723           CeedCallBackend(CeedVectorCreate(ceed, q_size, &active_inputs[num_active_in + field]));
724           CeedCallBackend(
725               CeedVectorSetArray(active_inputs[num_active_in + field], CEED_MEM_DEVICE, CEED_USE_POINTER, &q_vec_array[field * Q * num_elem]));
726         }
727         num_active_in += size;
728         CeedCallBackend(CeedVectorRestoreArray(impl->q_vecs_in[i], &q_vec_array));
729       }
730     }
731     impl->num_active_in = num_active_in;
732     impl->qf_active_in  = active_inputs;
733   }
734 
735   // Count number of active output fields
736   if (!num_active_out) {
737     for (CeedInt i = 0; i < num_output_fields; i++) {
738       CeedVector vec;
739 
740       // Get output vector
741       CeedCallBackend(CeedOperatorFieldGetVector(op_output_fields[i], &vec));
742       // Check if active output
743       if (vec == CEED_VECTOR_ACTIVE) {
744         CeedCallBackend(CeedQFunctionFieldGetSize(qf_output_fields[i], &size));
745         num_active_out += size;
746       }
747     }
748     impl->num_active_out = num_active_out;
749   }
750 
751   // Check sizes
752   CeedCheck(num_active_in > 0 && num_active_out > 0, ceed, CEED_ERROR_BACKEND, "Cannot assemble QFunction without active inputs and outputs");
753 
754   // Build objects if needed
755   if (build_objects) {
756     CeedSize l_size     = (CeedSize)num_elem * Q * num_active_in * num_active_out;
757     CeedInt  strides[3] = {1, num_elem * Q, Q}; /* *NOPAD* */
758 
759     // Create output restriction
760     CeedCallBackend(CeedElemRestrictionCreateStrided(ceed_parent, num_elem, Q, num_active_in * num_active_out,
761                                                      (CeedSize)num_active_in * (CeedSize)num_active_out * (CeedSize)num_elem * (CeedSize)Q, strides,
762                                                      rstr));
763     // Create assembled vector
764     CeedCallBackend(CeedVectorCreate(ceed_parent, l_size, assembled));
765   }
766   CeedCallBackend(CeedVectorSetValue(*assembled, 0.0));
767   CeedCallBackend(CeedVectorGetArray(*assembled, CEED_MEM_DEVICE, &assembled_array));
768 
769   // Input basis apply
770   CeedCallBackend(CeedOperatorInputBasis_Cuda(num_elem, qf_input_fields, op_input_fields, num_input_fields, true, e_data, impl));
771 
772   // Assemble QFunction
773   for (CeedInt in = 0; in < num_active_in; in++) {
774     // Set Inputs
775     CeedCallBackend(CeedVectorSetValue(active_inputs[in], 1.0));
776     if (num_active_in > 1) {
777       CeedCallBackend(CeedVectorSetValue(active_inputs[(in + num_active_in - 1) % num_active_in], 0.0));
778     }
779     // Set Outputs
780     for (CeedInt out = 0; out < num_output_fields; out++) {
781       CeedVector vec;
782 
783       // Get output vector
784       CeedCallBackend(CeedOperatorFieldGetVector(op_output_fields[out], &vec));
785       // Check if active output
786       if (vec == CEED_VECTOR_ACTIVE) {
787         CeedCallBackend(CeedVectorSetArray(impl->q_vecs_out[out], CEED_MEM_DEVICE, CEED_USE_POINTER, assembled_array));
788         CeedCallBackend(CeedQFunctionFieldGetSize(qf_output_fields[out], &size));
789         assembled_array += size * Q * num_elem;  // Advance the pointer by the size of the output
790       }
791     }
792     // Apply QFunction
793     CeedCallBackend(CeedQFunctionApply(qf, Q * num_elem, impl->q_vecs_in, impl->q_vecs_out));
794   }
795 
796   // Un-set output q_vecs to prevent accidental overwrite of Assembled
797   for (CeedInt out = 0; out < num_output_fields; out++) {
798     CeedVector vec;
799 
800     // Get output vector
801     CeedCallBackend(CeedOperatorFieldGetVector(op_output_fields[out], &vec));
802     // Check if active output
803     if (vec == CEED_VECTOR_ACTIVE) {
804       CeedCallBackend(CeedVectorTakeArray(impl->q_vecs_out[out], CEED_MEM_DEVICE, NULL));
805     }
806   }
807 
808   // Restore input arrays
809   CeedCallBackend(CeedOperatorRestoreInputs_Cuda(num_input_fields, qf_input_fields, op_input_fields, true, e_data, impl));
810 
811   // Restore output
812   CeedCallBackend(CeedVectorRestoreArray(*assembled, &assembled_array));
813   return CEED_ERROR_SUCCESS;
814 }
815 
816 //------------------------------------------------------------------------------
817 // Assemble Linear QFunction
818 //------------------------------------------------------------------------------
819 static int CeedOperatorLinearAssembleQFunction_Cuda(CeedOperator op, CeedVector *assembled, CeedElemRestriction *rstr, CeedRequest *request) {
820   return CeedOperatorLinearAssembleQFunctionCore_Cuda(op, true, assembled, rstr, request);
821 }
822 
823 //------------------------------------------------------------------------------
824 // Update Assembled Linear QFunction
825 //------------------------------------------------------------------------------
826 static int CeedOperatorLinearAssembleQFunctionUpdate_Cuda(CeedOperator op, CeedVector assembled, CeedElemRestriction rstr, CeedRequest *request) {
827   return CeedOperatorLinearAssembleQFunctionCore_Cuda(op, false, &assembled, &rstr, request);
828 }
829 
830 //------------------------------------------------------------------------------
831 // Assemble Diagonal Setup
832 //------------------------------------------------------------------------------
833 static inline int CeedOperatorAssembleDiagonalSetup_Cuda(CeedOperator op) {
834   Ceed                ceed;
835   CeedInt             num_input_fields, num_output_fields, num_eval_modes_in = 0, num_eval_modes_out = 0;
836   CeedInt             q_comp, num_nodes, num_qpts;
837   CeedEvalMode       *eval_modes_in = NULL, *eval_modes_out = NULL;
838   CeedBasis           basis_in = NULL, basis_out = NULL;
839   CeedQFunctionField *qf_fields;
840   CeedQFunction       qf;
841   CeedOperatorField  *op_fields;
842   CeedOperator_Cuda  *impl;
843 
844   CeedCallBackend(CeedOperatorGetCeed(op, &ceed));
845   CeedCallBackend(CeedOperatorGetQFunction(op, &qf));
846   CeedCallBackend(CeedQFunctionGetNumArgs(qf, &num_input_fields, &num_output_fields));
847 
848   // Determine active input basis
849   CeedCallBackend(CeedOperatorGetFields(op, NULL, &op_fields, NULL, NULL));
850   CeedCallBackend(CeedQFunctionGetFields(qf, NULL, &qf_fields, NULL, NULL));
851   for (CeedInt i = 0; i < num_input_fields; i++) {
852     CeedVector vec;
853 
854     CeedCallBackend(CeedOperatorFieldGetVector(op_fields[i], &vec));
855     if (vec == CEED_VECTOR_ACTIVE) {
856       CeedBasis    basis;
857       CeedEvalMode eval_mode;
858 
859       CeedCallBackend(CeedOperatorFieldGetBasis(op_fields[i], &basis));
860       CeedCheck(!basis_in || basis_in == basis, ceed, CEED_ERROR_BACKEND,
861                 "Backend does not implement operator diagonal assembly with multiple active bases");
862       basis_in = basis;
863       CeedCallBackend(CeedQFunctionFieldGetEvalMode(qf_fields[i], &eval_mode));
864       CeedCallBackend(CeedBasisGetNumQuadratureComponents(basis_in, eval_mode, &q_comp));
865       if (eval_mode != CEED_EVAL_WEIGHT) {
866         // q_comp = 1 if CEED_EVAL_NONE, CEED_EVAL_WEIGHT caught by QF assembly
867         CeedCallBackend(CeedRealloc(num_eval_modes_in + q_comp, &eval_modes_in));
868         for (CeedInt d = 0; d < q_comp; d++) eval_modes_in[num_eval_modes_in + d] = eval_mode;
869         num_eval_modes_in += q_comp;
870       }
871     }
872   }
873 
874   // Determine active output basis
875   CeedCallBackend(CeedOperatorGetFields(op, NULL, NULL, NULL, &op_fields));
876   CeedCallBackend(CeedQFunctionGetFields(qf, NULL, NULL, NULL, &qf_fields));
877   for (CeedInt i = 0; i < num_output_fields; i++) {
878     CeedVector vec;
879 
880     CeedCallBackend(CeedOperatorFieldGetVector(op_fields[i], &vec));
881     if (vec == CEED_VECTOR_ACTIVE) {
882       CeedBasis    basis;
883       CeedEvalMode eval_mode;
884 
885       CeedCallBackend(CeedOperatorFieldGetBasis(op_fields[i], &basis));
886       CeedCheck(!basis_out || basis_out == basis, ceed, CEED_ERROR_BACKEND,
887                 "Backend does not implement operator diagonal assembly with multiple active bases");
888       basis_out = basis;
889       CeedCallBackend(CeedQFunctionFieldGetEvalMode(qf_fields[i], &eval_mode));
890       CeedCallBackend(CeedBasisGetNumQuadratureComponents(basis_out, eval_mode, &q_comp));
891       if (eval_mode != CEED_EVAL_WEIGHT) {
892         // q_comp = 1 if CEED_EVAL_NONE, CEED_EVAL_WEIGHT caught by QF assembly
893         CeedCallBackend(CeedRealloc(num_eval_modes_out + q_comp, &eval_modes_out));
894         for (CeedInt d = 0; d < q_comp; d++) eval_modes_out[num_eval_modes_out + d] = eval_mode;
895         num_eval_modes_out += q_comp;
896       }
897     }
898   }
899 
900   // Operator data struct
901   CeedCallBackend(CeedOperatorGetData(op, &impl));
902   CeedCallBackend(CeedCalloc(1, &impl->diag));
903   CeedOperatorDiag_Cuda *diag = impl->diag;
904 
905   // Basis matrices
906   CeedCallBackend(CeedBasisGetNumNodes(basis_in, &num_nodes));
907   if (basis_in == CEED_BASIS_NONE) num_qpts = num_nodes;
908   else CeedCallBackend(CeedBasisGetNumQuadraturePoints(basis_in, &num_qpts));
909   const CeedInt interp_bytes     = num_nodes * num_qpts * sizeof(CeedScalar);
910   const CeedInt eval_modes_bytes = sizeof(CeedEvalMode);
911   bool          has_eval_none    = false;
912 
913   // CEED_EVAL_NONE
914   for (CeedInt i = 0; i < num_eval_modes_in; i++) has_eval_none = has_eval_none || (eval_modes_in[i] == CEED_EVAL_NONE);
915   for (CeedInt i = 0; i < num_eval_modes_out; i++) has_eval_none = has_eval_none || (eval_modes_out[i] == CEED_EVAL_NONE);
916   if (has_eval_none) {
917     CeedScalar *identity = NULL;
918 
919     CeedCallBackend(CeedCalloc(num_nodes * num_qpts, &identity));
920     for (CeedInt i = 0; i < (num_nodes < num_qpts ? num_nodes : num_qpts); i++) identity[i * num_nodes + i] = 1.0;
921     CeedCallCuda(ceed, cudaMalloc((void **)&diag->d_identity, interp_bytes));
922     CeedCallCuda(ceed, cudaMemcpy(diag->d_identity, identity, interp_bytes, cudaMemcpyHostToDevice));
923     CeedCallBackend(CeedFree(&identity));
924   }
925 
926   // CEED_EVAL_INTERP, CEED_EVAL_GRAD, CEED_EVAL_DIV, and CEED_EVAL_CURL
927   for (CeedInt in = 0; in < 2; in++) {
928     CeedFESpace fespace;
929     CeedBasis   basis = in ? basis_in : basis_out;
930 
931     CeedCallBackend(CeedBasisGetFESpace(basis, &fespace));
932     switch (fespace) {
933       case CEED_FE_SPACE_H1: {
934         CeedInt           q_comp_interp, q_comp_grad;
935         const CeedScalar *interp, *grad;
936         CeedScalar       *d_interp, *d_grad;
937 
938         CeedCallBackend(CeedBasisGetNumQuadratureComponents(basis, CEED_EVAL_INTERP, &q_comp_interp));
939         CeedCallBackend(CeedBasisGetNumQuadratureComponents(basis, CEED_EVAL_GRAD, &q_comp_grad));
940 
941         CeedCallBackend(CeedBasisGetInterp(basis, &interp));
942         CeedCallCuda(ceed, cudaMalloc((void **)&d_interp, interp_bytes * q_comp_interp));
943         CeedCallCuda(ceed, cudaMemcpy(d_interp, interp, interp_bytes * q_comp_interp, cudaMemcpyHostToDevice));
944         CeedCallBackend(CeedBasisGetGrad(basis, &grad));
945         CeedCallCuda(ceed, cudaMalloc((void **)&d_grad, interp_bytes * q_comp_grad));
946         CeedCallCuda(ceed, cudaMemcpy(d_grad, grad, interp_bytes * q_comp_grad, cudaMemcpyHostToDevice));
947         if (in) {
948           diag->d_interp_in = d_interp;
949           diag->d_grad_in   = d_grad;
950         } else {
951           diag->d_interp_out = d_interp;
952           diag->d_grad_out   = d_grad;
953         }
954       } break;
955       case CEED_FE_SPACE_HDIV: {
956         CeedInt           q_comp_interp, q_comp_div;
957         const CeedScalar *interp, *div;
958         CeedScalar       *d_interp, *d_div;
959 
960         CeedCallBackend(CeedBasisGetNumQuadratureComponents(basis, CEED_EVAL_INTERP, &q_comp_interp));
961         CeedCallBackend(CeedBasisGetNumQuadratureComponents(basis, CEED_EVAL_DIV, &q_comp_div));
962 
963         CeedCallBackend(CeedBasisGetInterp(basis, &interp));
964         CeedCallCuda(ceed, cudaMalloc((void **)&d_interp, interp_bytes * q_comp_interp));
965         CeedCallCuda(ceed, cudaMemcpy(d_interp, interp, interp_bytes * q_comp_interp, cudaMemcpyHostToDevice));
966         CeedCallBackend(CeedBasisGetDiv(basis, &div));
967         CeedCallCuda(ceed, cudaMalloc((void **)&d_div, interp_bytes * q_comp_div));
968         CeedCallCuda(ceed, cudaMemcpy(d_div, div, interp_bytes * q_comp_div, cudaMemcpyHostToDevice));
969         if (in) {
970           diag->d_interp_in = d_interp;
971           diag->d_div_in    = d_div;
972         } else {
973           diag->d_interp_out = d_interp;
974           diag->d_div_out    = d_div;
975         }
976       } break;
977       case CEED_FE_SPACE_HCURL: {
978         CeedInt           q_comp_interp, q_comp_curl;
979         const CeedScalar *interp, *curl;
980         CeedScalar       *d_interp, *d_curl;
981 
982         CeedCallBackend(CeedBasisGetNumQuadratureComponents(basis, CEED_EVAL_INTERP, &q_comp_interp));
983         CeedCallBackend(CeedBasisGetNumQuadratureComponents(basis, CEED_EVAL_CURL, &q_comp_curl));
984 
985         CeedCallBackend(CeedBasisGetInterp(basis, &interp));
986         CeedCallCuda(ceed, cudaMalloc((void **)&d_interp, interp_bytes * q_comp_interp));
987         CeedCallCuda(ceed, cudaMemcpy(d_interp, interp, interp_bytes * q_comp_interp, cudaMemcpyHostToDevice));
988         CeedCallBackend(CeedBasisGetCurl(basis, &curl));
989         CeedCallCuda(ceed, cudaMalloc((void **)&d_curl, interp_bytes * q_comp_curl));
990         CeedCallCuda(ceed, cudaMemcpy(d_curl, curl, interp_bytes * q_comp_curl, cudaMemcpyHostToDevice));
991         if (in) {
992           diag->d_interp_in = d_interp;
993           diag->d_curl_in   = d_curl;
994         } else {
995           diag->d_interp_out = d_interp;
996           diag->d_curl_out   = d_curl;
997         }
998       } break;
999     }
1000   }
1001 
1002   // Arrays of eval_modes
1003   CeedCallCuda(ceed, cudaMalloc((void **)&diag->d_eval_modes_in, num_eval_modes_in * eval_modes_bytes));
1004   CeedCallCuda(ceed, cudaMemcpy(diag->d_eval_modes_in, eval_modes_in, num_eval_modes_in * eval_modes_bytes, cudaMemcpyHostToDevice));
1005   CeedCallCuda(ceed, cudaMalloc((void **)&diag->d_eval_modes_out, num_eval_modes_out * eval_modes_bytes));
1006   CeedCallCuda(ceed, cudaMemcpy(diag->d_eval_modes_out, eval_modes_out, num_eval_modes_out * eval_modes_bytes, cudaMemcpyHostToDevice));
1007   CeedCallBackend(CeedFree(&eval_modes_in));
1008   CeedCallBackend(CeedFree(&eval_modes_out));
1009   return CEED_ERROR_SUCCESS;
1010 }
1011 
1012 //------------------------------------------------------------------------------
1013 // Assemble Diagonal Setup (Compilation)
1014 //------------------------------------------------------------------------------
1015 static inline int CeedOperatorAssembleDiagonalSetupCompile_Cuda(CeedOperator op, CeedInt use_ceedsize_idx, const bool is_point_block) {
1016   Ceed                ceed;
1017   char               *diagonal_kernel_source;
1018   const char         *diagonal_kernel_path;
1019   CeedInt             num_input_fields, num_output_fields, num_eval_modes_in = 0, num_eval_modes_out = 0;
1020   CeedInt             num_comp, q_comp, num_nodes, num_qpts;
1021   CeedBasis           basis_in = NULL, basis_out = NULL;
1022   CeedQFunctionField *qf_fields;
1023   CeedQFunction       qf;
1024   CeedOperatorField  *op_fields;
1025   CeedOperator_Cuda  *impl;
1026 
1027   CeedCallBackend(CeedOperatorGetCeed(op, &ceed));
1028   CeedCallBackend(CeedOperatorGetQFunction(op, &qf));
1029   CeedCallBackend(CeedQFunctionGetNumArgs(qf, &num_input_fields, &num_output_fields));
1030 
1031   // Determine active input basis
1032   CeedCallBackend(CeedOperatorGetFields(op, NULL, &op_fields, NULL, NULL));
1033   CeedCallBackend(CeedQFunctionGetFields(qf, NULL, &qf_fields, NULL, NULL));
1034   for (CeedInt i = 0; i < num_input_fields; i++) {
1035     CeedVector vec;
1036 
1037     CeedCallBackend(CeedOperatorFieldGetVector(op_fields[i], &vec));
1038     if (vec == CEED_VECTOR_ACTIVE) {
1039       CeedEvalMode eval_mode;
1040 
1041       CeedCallBackend(CeedOperatorFieldGetBasis(op_fields[i], &basis_in));
1042       CeedCallBackend(CeedQFunctionFieldGetEvalMode(qf_fields[i], &eval_mode));
1043       CeedCallBackend(CeedBasisGetNumQuadratureComponents(basis_in, eval_mode, &q_comp));
1044       if (eval_mode != CEED_EVAL_WEIGHT) {
1045         num_eval_modes_in += q_comp;
1046       }
1047     }
1048   }
1049 
1050   // Determine active output basis
1051   CeedCallBackend(CeedOperatorGetFields(op, NULL, NULL, NULL, &op_fields));
1052   CeedCallBackend(CeedQFunctionGetFields(qf, NULL, NULL, NULL, &qf_fields));
1053   for (CeedInt i = 0; i < num_output_fields; i++) {
1054     CeedVector vec;
1055 
1056     CeedCallBackend(CeedOperatorFieldGetVector(op_fields[i], &vec));
1057     if (vec == CEED_VECTOR_ACTIVE) {
1058       CeedEvalMode eval_mode;
1059 
1060       CeedCallBackend(CeedOperatorFieldGetBasis(op_fields[i], &basis_out));
1061       CeedCallBackend(CeedQFunctionFieldGetEvalMode(qf_fields[i], &eval_mode));
1062       CeedCallBackend(CeedBasisGetNumQuadratureComponents(basis_out, eval_mode, &q_comp));
1063       if (eval_mode != CEED_EVAL_WEIGHT) {
1064         num_eval_modes_out += q_comp;
1065       }
1066     }
1067   }
1068 
1069   // Operator data struct
1070   CeedCallBackend(CeedOperatorGetData(op, &impl));
1071   CeedOperatorDiag_Cuda *diag = impl->diag;
1072 
1073   // Assemble kernel
1074   CUmodule *module          = is_point_block ? &diag->module_point_block : &diag->module;
1075   CeedInt   elems_per_block = 1;
1076   CeedCallBackend(CeedBasisGetNumNodes(basis_in, &num_nodes));
1077   CeedCallBackend(CeedBasisGetNumComponents(basis_in, &num_comp));
1078   if (basis_in == CEED_BASIS_NONE) num_qpts = num_nodes;
1079   else CeedCallBackend(CeedBasisGetNumQuadraturePoints(basis_in, &num_qpts));
1080   CeedCallBackend(CeedGetJitAbsolutePath(ceed, "ceed/jit-source/cuda/cuda-ref-operator-assemble-diagonal.h", &diagonal_kernel_path));
1081   CeedDebug256(ceed, CEED_DEBUG_COLOR_SUCCESS, "----- Loading Diagonal Assembly Kernel Source -----\n");
1082   CeedCallBackend(CeedLoadSourceToBuffer(ceed, diagonal_kernel_path, &diagonal_kernel_source));
1083   CeedDebug256(ceed, CEED_DEBUG_COLOR_SUCCESS, "----- Loading Diagonal Assembly Source Complete! -----\n");
1084   CeedCallCuda(ceed, CeedCompile_Cuda(ceed, diagonal_kernel_source, module, 8, "NUM_EVAL_MODES_IN", num_eval_modes_in, "NUM_EVAL_MODES_OUT",
1085                                       num_eval_modes_out, "NUM_COMP", num_comp, "NUM_NODES", num_nodes, "NUM_QPTS", num_qpts, "USE_CEEDSIZE",
1086                                       use_ceedsize_idx, "USE_POINT_BLOCK", is_point_block ? 1 : 0, "BLOCK_SIZE", num_nodes * elems_per_block));
1087   CeedCallCuda(ceed, CeedGetKernel_Cuda(ceed, *module, "LinearDiagonal", is_point_block ? &diag->LinearPointBlock : &diag->LinearDiagonal));
1088   CeedCallBackend(CeedFree(&diagonal_kernel_path));
1089   CeedCallBackend(CeedFree(&diagonal_kernel_source));
1090   return CEED_ERROR_SUCCESS;
1091 }
1092 
1093 //------------------------------------------------------------------------------
1094 // Assemble Diagonal Core
1095 //------------------------------------------------------------------------------
1096 static inline int CeedOperatorAssembleDiagonalCore_Cuda(CeedOperator op, CeedVector assembled, CeedRequest *request, const bool is_point_block) {
1097   Ceed                ceed;
1098   CeedInt             num_elem, num_nodes;
1099   CeedScalar         *elem_diag_array;
1100   const CeedScalar   *assembled_qf_array;
1101   CeedVector          assembled_qf   = NULL, elem_diag;
1102   CeedElemRestriction assembled_rstr = NULL, rstr_in, rstr_out, diag_rstr;
1103   CeedOperator_Cuda  *impl;
1104 
1105   CeedCallBackend(CeedOperatorGetCeed(op, &ceed));
1106   CeedCallBackend(CeedOperatorGetData(op, &impl));
1107 
1108   // Assemble QFunction
1109   CeedCallBackend(CeedOperatorLinearAssembleQFunctionBuildOrUpdate(op, &assembled_qf, &assembled_rstr, request));
1110   CeedCallBackend(CeedElemRestrictionDestroy(&assembled_rstr));
1111   CeedCallBackend(CeedVectorGetArrayRead(assembled_qf, CEED_MEM_DEVICE, &assembled_qf_array));
1112 
1113   // Setup
1114   if (!impl->diag) CeedCallBackend(CeedOperatorAssembleDiagonalSetup_Cuda(op));
1115   CeedOperatorDiag_Cuda *diag = impl->diag;
1116 
1117   assert(diag != NULL);
1118 
1119   // Assemble kernel if needed
1120   if ((!is_point_block && !diag->LinearDiagonal) || (is_point_block && !diag->LinearPointBlock)) {
1121     CeedSize assembled_length, assembled_qf_length;
1122     CeedInt  use_ceedsize_idx = 0;
1123     CeedCallBackend(CeedVectorGetLength(assembled, &assembled_length));
1124     CeedCallBackend(CeedVectorGetLength(assembled_qf, &assembled_qf_length));
1125     if ((assembled_length > INT_MAX) || (assembled_qf_length > INT_MAX)) use_ceedsize_idx = 1;
1126 
1127     CeedCallBackend(CeedOperatorAssembleDiagonalSetupCompile_Cuda(op, use_ceedsize_idx, is_point_block));
1128   }
1129 
1130   // Restriction and diagonal vector
1131   CeedCallBackend(CeedOperatorGetActiveElemRestrictions(op, &rstr_in, &rstr_out));
1132   CeedCheck(rstr_in == rstr_out, ceed, CEED_ERROR_BACKEND,
1133             "Cannot assemble operator diagonal with different input and output active element restrictions");
1134   if (!is_point_block && !diag->diag_rstr) {
1135     CeedCallBackend(CeedElemRestrictionCreateUnsignedCopy(rstr_out, &diag->diag_rstr));
1136     CeedCallBackend(CeedElemRestrictionCreateVector(diag->diag_rstr, NULL, &diag->elem_diag));
1137   } else if (is_point_block && !diag->point_block_diag_rstr) {
1138     CeedCallBackend(CeedOperatorCreateActivePointBlockRestriction(rstr_out, &diag->point_block_diag_rstr));
1139     CeedCallBackend(CeedElemRestrictionCreateVector(diag->point_block_diag_rstr, NULL, &diag->point_block_elem_diag));
1140   }
1141   diag_rstr = is_point_block ? diag->point_block_diag_rstr : diag->diag_rstr;
1142   elem_diag = is_point_block ? diag->point_block_elem_diag : diag->elem_diag;
1143   CeedCallBackend(CeedVectorSetValue(elem_diag, 0.0));
1144 
1145   // Only assemble diagonal if the basis has nodes, otherwise inputs are null pointers
1146   CeedCallBackend(CeedElemRestrictionGetElementSize(diag_rstr, &num_nodes));
1147   if (num_nodes > 0) {
1148     // Assemble element operator diagonals
1149     CeedCallBackend(CeedElemRestrictionGetNumElements(diag_rstr, &num_elem));
1150     CeedCallBackend(CeedVectorGetArray(elem_diag, CEED_MEM_DEVICE, &elem_diag_array));
1151 
1152     // Compute the diagonal of B^T D B
1153     CeedInt elems_per_block = 1;
1154     CeedInt grid            = CeedDivUpInt(num_elem, elems_per_block);
1155     void   *args[]          = {(void *)&num_elem,      &diag->d_identity,       &diag->d_interp_in,  &diag->d_grad_in, &diag->d_div_in,
1156                                &diag->d_curl_in,       &diag->d_interp_out,     &diag->d_grad_out,   &diag->d_div_out, &diag->d_curl_out,
1157                                &diag->d_eval_modes_in, &diag->d_eval_modes_out, &assembled_qf_array, &elem_diag_array};
1158 
1159     if (is_point_block) {
1160       CeedCallBackend(CeedRunKernelDim_Cuda(ceed, diag->LinearPointBlock, grid, num_nodes, 1, elems_per_block, args));
1161     } else {
1162       CeedCallBackend(CeedRunKernelDim_Cuda(ceed, diag->LinearDiagonal, grid, num_nodes, 1, elems_per_block, args));
1163     }
1164 
1165     // Restore arrays
1166     CeedCallBackend(CeedVectorRestoreArray(elem_diag, &elem_diag_array));
1167     CeedCallBackend(CeedVectorRestoreArrayRead(assembled_qf, &assembled_qf_array));
1168   }
1169 
1170   // Assemble local operator diagonal
1171   CeedCallBackend(CeedElemRestrictionApply(diag_rstr, CEED_TRANSPOSE, elem_diag, assembled, request));
1172 
1173   // Cleanup
1174   CeedCallBackend(CeedVectorDestroy(&assembled_qf));
1175   return CEED_ERROR_SUCCESS;
1176 }
1177 
1178 //------------------------------------------------------------------------------
1179 // Assemble Linear Diagonal
1180 //------------------------------------------------------------------------------
1181 static int CeedOperatorLinearAssembleAddDiagonal_Cuda(CeedOperator op, CeedVector assembled, CeedRequest *request) {
1182   CeedCallBackend(CeedOperatorAssembleDiagonalCore_Cuda(op, assembled, request, false));
1183   return CEED_ERROR_SUCCESS;
1184 }
1185 
1186 //------------------------------------------------------------------------------
1187 // Assemble Linear Point Block Diagonal
1188 //------------------------------------------------------------------------------
1189 static int CeedOperatorLinearAssembleAddPointBlockDiagonal_Cuda(CeedOperator op, CeedVector assembled, CeedRequest *request) {
1190   CeedCallBackend(CeedOperatorAssembleDiagonalCore_Cuda(op, assembled, request, true));
1191   return CEED_ERROR_SUCCESS;
1192 }
1193 
1194 //------------------------------------------------------------------------------
1195 // Single Operator Assembly Setup
1196 //------------------------------------------------------------------------------
1197 static int CeedSingleOperatorAssembleSetup_Cuda(CeedOperator op, CeedInt use_ceedsize_idx) {
1198   Ceed                ceed;
1199   Ceed_Cuda          *cuda_data;
1200   char               *assembly_kernel_source;
1201   const char         *assembly_kernel_path;
1202   CeedInt             num_input_fields, num_output_fields, num_eval_modes_in = 0, num_eval_modes_out = 0;
1203   CeedInt             elem_size_in, num_qpts_in = 0, num_comp_in, elem_size_out, num_qpts_out, num_comp_out, q_comp;
1204   CeedEvalMode       *eval_modes_in = NULL, *eval_modes_out = NULL;
1205   CeedElemRestriction rstr_in = NULL, rstr_out = NULL;
1206   CeedBasis           basis_in = NULL, basis_out = NULL;
1207   CeedQFunctionField *qf_fields;
1208   CeedQFunction       qf;
1209   CeedOperatorField  *input_fields, *output_fields;
1210   CeedOperator_Cuda  *impl;
1211 
1212   CeedCallBackend(CeedOperatorGetCeed(op, &ceed));
1213   CeedCallBackend(CeedOperatorGetData(op, &impl));
1214 
1215   // Get intput and output fields
1216   CeedCallBackend(CeedOperatorGetFields(op, &num_input_fields, &input_fields, &num_output_fields, &output_fields));
1217 
1218   // Determine active input basis eval mode
1219   CeedCallBackend(CeedOperatorGetQFunction(op, &qf));
1220   CeedCallBackend(CeedQFunctionGetFields(qf, NULL, &qf_fields, NULL, NULL));
1221   for (CeedInt i = 0; i < num_input_fields; i++) {
1222     CeedVector vec;
1223 
1224     CeedCallBackend(CeedOperatorFieldGetVector(input_fields[i], &vec));
1225     if (vec == CEED_VECTOR_ACTIVE) {
1226       CeedBasis    basis;
1227       CeedEvalMode eval_mode;
1228 
1229       CeedCallBackend(CeedOperatorFieldGetBasis(input_fields[i], &basis));
1230       CeedCheck(!basis_in || basis_in == basis, ceed, CEED_ERROR_BACKEND, "Backend does not implement operator assembly with multiple active bases");
1231       basis_in = basis;
1232       CeedCallBackend(CeedOperatorFieldGetElemRestriction(input_fields[i], &rstr_in));
1233       CeedCallBackend(CeedElemRestrictionGetElementSize(rstr_in, &elem_size_in));
1234       if (basis_in == CEED_BASIS_NONE) num_qpts_in = elem_size_in;
1235       else CeedCallBackend(CeedBasisGetNumQuadraturePoints(basis_in, &num_qpts_in));
1236       CeedCallBackend(CeedQFunctionFieldGetEvalMode(qf_fields[i], &eval_mode));
1237       CeedCallBackend(CeedBasisGetNumQuadratureComponents(basis_in, eval_mode, &q_comp));
1238       if (eval_mode != CEED_EVAL_WEIGHT) {
1239         // q_comp = 1 if CEED_EVAL_NONE, CEED_EVAL_WEIGHT caught by QF Assembly
1240         CeedCallBackend(CeedRealloc(num_eval_modes_in + q_comp, &eval_modes_in));
1241         for (CeedInt d = 0; d < q_comp; d++) {
1242           eval_modes_in[num_eval_modes_in + d] = eval_mode;
1243         }
1244         num_eval_modes_in += q_comp;
1245       }
1246     }
1247   }
1248 
1249   // Determine active output basis; basis_out and rstr_out only used if same as input, TODO
1250   CeedCallBackend(CeedQFunctionGetFields(qf, NULL, NULL, NULL, &qf_fields));
1251   for (CeedInt i = 0; i < num_output_fields; i++) {
1252     CeedVector vec;
1253 
1254     CeedCallBackend(CeedOperatorFieldGetVector(output_fields[i], &vec));
1255     if (vec == CEED_VECTOR_ACTIVE) {
1256       CeedBasis    basis;
1257       CeedEvalMode eval_mode;
1258 
1259       CeedCallBackend(CeedOperatorFieldGetBasis(output_fields[i], &basis));
1260       CeedCheck(!basis_out || basis_out == basis, ceed, CEED_ERROR_BACKEND,
1261                 "Backend does not implement operator assembly with multiple active bases");
1262       basis_out = basis;
1263       CeedCallBackend(CeedOperatorFieldGetElemRestriction(output_fields[i], &rstr_out));
1264       CeedCallBackend(CeedElemRestrictionGetElementSize(rstr_out, &elem_size_out));
1265       if (basis_out == CEED_BASIS_NONE) num_qpts_out = elem_size_out;
1266       else CeedCallBackend(CeedBasisGetNumQuadraturePoints(basis_out, &num_qpts_out));
1267       CeedCheck(num_qpts_in == num_qpts_out, ceed, CEED_ERROR_UNSUPPORTED,
1268                 "Active input and output bases must have the same number of quadrature points");
1269       CeedCallBackend(CeedQFunctionFieldGetEvalMode(qf_fields[i], &eval_mode));
1270       CeedCallBackend(CeedBasisGetNumQuadratureComponents(basis_out, eval_mode, &q_comp));
1271       if (eval_mode != CEED_EVAL_WEIGHT) {
1272         // q_comp = 1 if CEED_EVAL_NONE, CEED_EVAL_WEIGHT caught by QF Assembly
1273         CeedCallBackend(CeedRealloc(num_eval_modes_out + q_comp, &eval_modes_out));
1274         for (CeedInt d = 0; d < q_comp; d++) {
1275           eval_modes_out[num_eval_modes_out + d] = eval_mode;
1276         }
1277         num_eval_modes_out += q_comp;
1278       }
1279     }
1280   }
1281   CeedCheck(num_eval_modes_in > 0 && num_eval_modes_out > 0, ceed, CEED_ERROR_UNSUPPORTED, "Cannot assemble operator without inputs/outputs");
1282 
1283   CeedCallBackend(CeedCalloc(1, &impl->asmb));
1284   CeedOperatorAssemble_Cuda *asmb = impl->asmb;
1285   asmb->elems_per_block           = 1;
1286   asmb->block_size_x              = elem_size_in;
1287   asmb->block_size_y              = elem_size_out;
1288 
1289   CeedCallBackend(CeedGetData(ceed, &cuda_data));
1290   bool fallback = asmb->block_size_x * asmb->block_size_y * asmb->elems_per_block > cuda_data->device_prop.maxThreadsPerBlock;
1291 
1292   if (fallback) {
1293     // Use fallback kernel with 1D threadblock
1294     asmb->block_size_y = 1;
1295   }
1296 
1297   // Compile kernels
1298   CeedCallBackend(CeedElemRestrictionGetNumComponents(rstr_in, &num_comp_in));
1299   CeedCallBackend(CeedElemRestrictionGetNumComponents(rstr_out, &num_comp_out));
1300   CeedCallBackend(CeedGetJitAbsolutePath(ceed, "ceed/jit-source/cuda/cuda-ref-operator-assemble.h", &assembly_kernel_path));
1301   CeedDebug256(ceed, CEED_DEBUG_COLOR_SUCCESS, "----- Loading Assembly Kernel Source -----\n");
1302   CeedCallBackend(CeedLoadSourceToBuffer(ceed, assembly_kernel_path, &assembly_kernel_source));
1303   CeedDebug256(ceed, CEED_DEBUG_COLOR_SUCCESS, "----- Loading Assembly Source Complete! -----\n");
1304   CeedCallBackend(CeedCompile_Cuda(ceed, assembly_kernel_source, &asmb->module, 10, "NUM_EVAL_MODES_IN", num_eval_modes_in, "NUM_EVAL_MODES_OUT",
1305                                    num_eval_modes_out, "NUM_COMP_IN", num_comp_in, "NUM_COMP_OUT", num_comp_out, "NUM_NODES_IN", elem_size_in,
1306                                    "NUM_NODES_OUT", elem_size_out, "NUM_QPTS", num_qpts_in, "BLOCK_SIZE",
1307                                    asmb->block_size_x * asmb->block_size_y * asmb->elems_per_block, "BLOCK_SIZE_Y", asmb->block_size_y,
1308                                    "USE_CEEDSIZE", use_ceedsize_idx));
1309   CeedCallBackend(CeedGetKernel_Cuda(ceed, asmb->module, "LinearAssemble", &asmb->LinearAssemble));
1310   CeedCallBackend(CeedFree(&assembly_kernel_path));
1311   CeedCallBackend(CeedFree(&assembly_kernel_source));
1312 
1313   // Load into B_in, in order that they will be used in eval_modes_in
1314   {
1315     const CeedInt in_bytes           = elem_size_in * num_qpts_in * num_eval_modes_in * sizeof(CeedScalar);
1316     CeedInt       d_in               = 0;
1317     CeedEvalMode  eval_modes_in_prev = CEED_EVAL_NONE;
1318     bool          has_eval_none      = false;
1319     CeedScalar   *identity           = NULL;
1320 
1321     for (CeedInt i = 0; i < num_eval_modes_in; i++) {
1322       has_eval_none = has_eval_none || (eval_modes_in[i] == CEED_EVAL_NONE);
1323     }
1324     if (has_eval_none) {
1325       CeedCallBackend(CeedCalloc(elem_size_in * num_qpts_in, &identity));
1326       for (CeedInt i = 0; i < (elem_size_in < num_qpts_in ? elem_size_in : num_qpts_in); i++) identity[i * elem_size_in + i] = 1.0;
1327     }
1328 
1329     CeedCallCuda(ceed, cudaMalloc((void **)&asmb->d_B_in, in_bytes));
1330     for (CeedInt i = 0; i < num_eval_modes_in; i++) {
1331       const CeedScalar *h_B_in;
1332 
1333       CeedCallBackend(CeedOperatorGetBasisPointer(basis_in, eval_modes_in[i], identity, &h_B_in));
1334       CeedCallBackend(CeedBasisGetNumQuadratureComponents(basis_in, eval_modes_in[i], &q_comp));
1335       if (q_comp > 1) {
1336         if (i == 0 || eval_modes_in[i] != eval_modes_in_prev) d_in = 0;
1337         else h_B_in = &h_B_in[(++d_in) * elem_size_in * num_qpts_in];
1338       }
1339       eval_modes_in_prev = eval_modes_in[i];
1340 
1341       CeedCallCuda(ceed, cudaMemcpy(&asmb->d_B_in[i * elem_size_in * num_qpts_in], h_B_in, elem_size_in * num_qpts_in * sizeof(CeedScalar),
1342                                     cudaMemcpyHostToDevice));
1343     }
1344 
1345     if (identity) {
1346       CeedCallBackend(CeedFree(&identity));
1347     }
1348   }
1349 
1350   // Load into B_out, in order that they will be used in eval_modes_out
1351   {
1352     const CeedInt out_bytes           = elem_size_out * num_qpts_out * num_eval_modes_out * sizeof(CeedScalar);
1353     CeedInt       d_out               = 0;
1354     CeedEvalMode  eval_modes_out_prev = CEED_EVAL_NONE;
1355     bool          has_eval_none       = false;
1356     CeedScalar   *identity            = NULL;
1357 
1358     for (CeedInt i = 0; i < num_eval_modes_out; i++) {
1359       has_eval_none = has_eval_none || (eval_modes_out[i] == CEED_EVAL_NONE);
1360     }
1361     if (has_eval_none) {
1362       CeedCallBackend(CeedCalloc(elem_size_out * num_qpts_out, &identity));
1363       for (CeedInt i = 0; i < (elem_size_out < num_qpts_out ? elem_size_out : num_qpts_out); i++) identity[i * elem_size_out + i] = 1.0;
1364     }
1365 
1366     CeedCallCuda(ceed, cudaMalloc((void **)&asmb->d_B_out, out_bytes));
1367     for (CeedInt i = 0; i < num_eval_modes_out; i++) {
1368       const CeedScalar *h_B_out;
1369 
1370       CeedCallBackend(CeedOperatorGetBasisPointer(basis_out, eval_modes_out[i], identity, &h_B_out));
1371       CeedCallBackend(CeedBasisGetNumQuadratureComponents(basis_out, eval_modes_out[i], &q_comp));
1372       if (q_comp > 1) {
1373         if (i == 0 || eval_modes_out[i] != eval_modes_out_prev) d_out = 0;
1374         else h_B_out = &h_B_out[(++d_out) * elem_size_out * num_qpts_out];
1375       }
1376       eval_modes_out_prev = eval_modes_out[i];
1377 
1378       CeedCallCuda(ceed, cudaMemcpy(&asmb->d_B_out[i * elem_size_out * num_qpts_out], h_B_out, elem_size_out * num_qpts_out * sizeof(CeedScalar),
1379                                     cudaMemcpyHostToDevice));
1380     }
1381 
1382     if (identity) {
1383       CeedCallBackend(CeedFree(&identity));
1384     }
1385   }
1386   return CEED_ERROR_SUCCESS;
1387 }
1388 
1389 //------------------------------------------------------------------------------
1390 // Assemble matrix data for COO matrix of assembled operator.
1391 // The sparsity pattern is set by CeedOperatorLinearAssembleSymbolic.
1392 //
1393 // Note that this (and other assembly routines) currently assume only one active input restriction/basis per operator (could have multiple basis eval
1394 // modes).
1395 // TODO: allow multiple active input restrictions/basis objects
1396 //------------------------------------------------------------------------------
1397 static int CeedSingleOperatorAssemble_Cuda(CeedOperator op, CeedInt offset, CeedVector values) {
1398   Ceed                ceed;
1399   CeedSize            values_length = 0, assembled_qf_length = 0;
1400   CeedInt             use_ceedsize_idx = 0, num_elem_in, num_elem_out, elem_size_in, elem_size_out;
1401   CeedScalar         *values_array;
1402   const CeedScalar   *assembled_qf_array;
1403   CeedVector          assembled_qf   = NULL;
1404   CeedElemRestriction assembled_rstr = NULL, rstr_in, rstr_out;
1405   CeedRestrictionType rstr_type_in, rstr_type_out;
1406   const bool         *orients_in = NULL, *orients_out = NULL;
1407   const CeedInt8     *curl_orients_in = NULL, *curl_orients_out = NULL;
1408   CeedOperator_Cuda  *impl;
1409 
1410   CeedCallBackend(CeedOperatorGetCeed(op, &ceed));
1411   CeedCallBackend(CeedOperatorGetData(op, &impl));
1412 
1413   // Assemble QFunction
1414   CeedCallBackend(CeedOperatorLinearAssembleQFunctionBuildOrUpdate(op, &assembled_qf, &assembled_rstr, CEED_REQUEST_IMMEDIATE));
1415   CeedCallBackend(CeedElemRestrictionDestroy(&assembled_rstr));
1416   CeedCallBackend(CeedVectorGetArrayRead(assembled_qf, CEED_MEM_DEVICE, &assembled_qf_array));
1417 
1418   CeedCallBackend(CeedVectorGetLength(values, &values_length));
1419   CeedCallBackend(CeedVectorGetLength(assembled_qf, &assembled_qf_length));
1420   if ((values_length > INT_MAX) || (assembled_qf_length > INT_MAX)) use_ceedsize_idx = 1;
1421 
1422   // Setup
1423   if (!impl->asmb) CeedCallBackend(CeedSingleOperatorAssembleSetup_Cuda(op, use_ceedsize_idx));
1424   CeedOperatorAssemble_Cuda *asmb = impl->asmb;
1425 
1426   assert(asmb != NULL);
1427 
1428   // Assemble element operator
1429   CeedCallBackend(CeedVectorGetArray(values, CEED_MEM_DEVICE, &values_array));
1430   values_array += offset;
1431 
1432   CeedCallBackend(CeedOperatorGetActiveElemRestrictions(op, &rstr_in, &rstr_out));
1433   CeedCallBackend(CeedElemRestrictionGetNumElements(rstr_in, &num_elem_in));
1434   CeedCallBackend(CeedElemRestrictionGetElementSize(rstr_in, &elem_size_in));
1435 
1436   CeedCallBackend(CeedElemRestrictionGetType(rstr_in, &rstr_type_in));
1437   if (rstr_type_in == CEED_RESTRICTION_ORIENTED) {
1438     CeedCallBackend(CeedElemRestrictionGetOrientations(rstr_in, CEED_MEM_DEVICE, &orients_in));
1439   } else if (rstr_type_in == CEED_RESTRICTION_CURL_ORIENTED) {
1440     CeedCallBackend(CeedElemRestrictionGetCurlOrientations(rstr_in, CEED_MEM_DEVICE, &curl_orients_in));
1441   }
1442 
1443   if (rstr_in != rstr_out) {
1444     CeedCallBackend(CeedElemRestrictionGetNumElements(rstr_out, &num_elem_out));
1445     CeedCheck(num_elem_in == num_elem_out, ceed, CEED_ERROR_UNSUPPORTED,
1446               "Active input and output operator restrictions must have the same number of elements");
1447     CeedCallBackend(CeedElemRestrictionGetElementSize(rstr_out, &elem_size_out));
1448 
1449     CeedCallBackend(CeedElemRestrictionGetType(rstr_out, &rstr_type_out));
1450     if (rstr_type_out == CEED_RESTRICTION_ORIENTED) {
1451       CeedCallBackend(CeedElemRestrictionGetOrientations(rstr_out, CEED_MEM_DEVICE, &orients_out));
1452     } else if (rstr_type_out == CEED_RESTRICTION_CURL_ORIENTED) {
1453       CeedCallBackend(CeedElemRestrictionGetCurlOrientations(rstr_out, CEED_MEM_DEVICE, &curl_orients_out));
1454     }
1455   } else {
1456     elem_size_out    = elem_size_in;
1457     orients_out      = orients_in;
1458     curl_orients_out = curl_orients_in;
1459   }
1460 
1461   // Compute B^T D B
1462   CeedInt shared_mem =
1463       ((curl_orients_in || curl_orients_out ? elem_size_in * elem_size_out : 0) + (curl_orients_in ? elem_size_in * asmb->block_size_y : 0)) *
1464       sizeof(CeedScalar);
1465   CeedInt grid   = CeedDivUpInt(num_elem_in, asmb->elems_per_block);
1466   void   *args[] = {(void *)&num_elem_in, &asmb->d_B_in,     &asmb->d_B_out,      &orients_in,  &curl_orients_in,
1467                     &orients_out,         &curl_orients_out, &assembled_qf_array, &values_array};
1468 
1469   CeedCallBackend(
1470       CeedRunKernelDimShared_Cuda(ceed, asmb->LinearAssemble, grid, asmb->block_size_x, asmb->block_size_y, asmb->elems_per_block, shared_mem, args));
1471 
1472   // Restore arrays
1473   CeedCallBackend(CeedVectorRestoreArray(values, &values_array));
1474   CeedCallBackend(CeedVectorRestoreArrayRead(assembled_qf, &assembled_qf_array));
1475 
1476   // Cleanup
1477   CeedCallBackend(CeedVectorDestroy(&assembled_qf));
1478   if (rstr_type_in == CEED_RESTRICTION_ORIENTED) {
1479     CeedCallBackend(CeedElemRestrictionRestoreOrientations(rstr_in, &orients_in));
1480   } else if (rstr_type_in == CEED_RESTRICTION_CURL_ORIENTED) {
1481     CeedCallBackend(CeedElemRestrictionRestoreCurlOrientations(rstr_in, &curl_orients_in));
1482   }
1483   if (rstr_in != rstr_out) {
1484     if (rstr_type_out == CEED_RESTRICTION_ORIENTED) {
1485       CeedCallBackend(CeedElemRestrictionRestoreOrientations(rstr_out, &orients_out));
1486     } else if (rstr_type_out == CEED_RESTRICTION_CURL_ORIENTED) {
1487       CeedCallBackend(CeedElemRestrictionRestoreCurlOrientations(rstr_out, &curl_orients_out));
1488     }
1489   }
1490   return CEED_ERROR_SUCCESS;
1491 }
1492 
1493 //------------------------------------------------------------------------------
1494 // Assemble Linear QFunction AtPoints
1495 //------------------------------------------------------------------------------
1496 static int CeedOperatorLinearAssembleQFunctionAtPoints_Cuda(CeedOperator op, CeedVector *assembled, CeedElemRestriction *rstr, CeedRequest *request) {
1497   return CeedError(CeedOperatorReturnCeed(op), CEED_ERROR_BACKEND, "Backend does not implement CeedOperatorLinearAssembleQFunction");
1498 }
1499 
1500 //------------------------------------------------------------------------------
1501 // Assemble Linear Diagonal AtPoints
1502 //------------------------------------------------------------------------------
1503 static int CeedOperatorLinearAssembleAddDiagonalAtPoints_Cuda(CeedOperator op, CeedVector assembled, CeedRequest *request) {
1504   CeedInt             max_num_points, num_elem, num_input_fields, num_output_fields;
1505   CeedScalar         *e_data[2 * CEED_FIELD_MAX] = {NULL};
1506   CeedQFunctionField *qf_input_fields, *qf_output_fields;
1507   CeedQFunction       qf;
1508   CeedOperatorField  *op_input_fields, *op_output_fields;
1509   CeedOperator_Cuda  *impl;
1510 
1511   CeedCallBackend(CeedOperatorGetData(op, &impl));
1512   CeedCallBackend(CeedOperatorGetQFunction(op, &qf));
1513   CeedCallBackend(CeedOperatorGetNumElements(op, &num_elem));
1514   CeedCallBackend(CeedOperatorGetFields(op, &num_input_fields, &op_input_fields, &num_output_fields, &op_output_fields));
1515   CeedCallBackend(CeedQFunctionGetFields(qf, NULL, &qf_input_fields, NULL, &qf_output_fields));
1516   CeedInt num_points[num_elem];
1517 
1518   // Setup
1519   CeedCallBackend(CeedOperatorSetupAtPoints_Cuda(op));
1520   max_num_points = impl->max_num_points;
1521   for (CeedInt i = 0; i < num_elem; i++) num_points[i] = max_num_points;
1522 
1523   // Input Evecs and Restriction
1524   CeedCallBackend(CeedOperatorSetupInputs_Cuda(num_input_fields, qf_input_fields, op_input_fields, NULL, true, e_data, impl, request));
1525 
1526   // Get point coordinates
1527   if (!impl->point_coords_elem) {
1528     CeedVector          point_coords = NULL;
1529     CeedElemRestriction rstr_points  = NULL;
1530 
1531     CeedCallBackend(CeedOperatorAtPointsGetPoints(op, &rstr_points, &point_coords));
1532     CeedCallBackend(CeedElemRestrictionCreateVector(rstr_points, NULL, &impl->point_coords_elem));
1533     CeedCallBackend(CeedElemRestrictionApply(rstr_points, CEED_NOTRANSPOSE, point_coords, impl->point_coords_elem, request));
1534   }
1535 
1536   // Clear active input Qvecs
1537   for (CeedInt i = 0; i < num_input_fields; i++) {
1538     CeedVector vec;
1539 
1540     CeedCallBackend(CeedOperatorFieldGetVector(op_input_fields[i], &vec));
1541     if (vec != CEED_VECTOR_ACTIVE) continue;
1542     CeedCallBackend(CeedVectorSetValue(impl->q_vecs_in[i], 0.0));
1543   }
1544 
1545   // Input basis apply if needed
1546   CeedCallBackend(CeedOperatorInputBasisAtPoints_Cuda(num_elem, num_points, qf_input_fields, op_input_fields, num_input_fields, true, e_data, impl));
1547 
1548   // Output pointers, as necessary
1549   for (CeedInt i = 0; i < num_output_fields; i++) {
1550     CeedEvalMode eval_mode;
1551 
1552     CeedCallBackend(CeedQFunctionFieldGetEvalMode(qf_output_fields[i], &eval_mode));
1553     if (eval_mode == CEED_EVAL_NONE) {
1554       // Set the output Q-Vector to use the E-Vector data directly.
1555       CeedCallBackend(CeedVectorGetArrayWrite(impl->e_vecs[i + impl->num_inputs], CEED_MEM_DEVICE, &e_data[i + num_input_fields]));
1556       CeedCallBackend(CeedVectorSetArray(impl->q_vecs_out[i], CEED_MEM_DEVICE, CEED_USE_POINTER, e_data[i + num_input_fields]));
1557     }
1558   }
1559 
1560   // Loop over active fields
1561   for (CeedInt i = 0; i < num_input_fields; i++) {
1562     bool                is_active_at_points = true;
1563     CeedInt             elem_size = 1, num_comp_active = 1, e_vec_size = 0;
1564     CeedRestrictionType rstr_type;
1565     CeedVector          vec;
1566     CeedElemRestriction elem_rstr;
1567 
1568     CeedCallBackend(CeedOperatorFieldGetVector(op_input_fields[i], &vec));
1569     // -- Skip non-active input
1570     if (vec != CEED_VECTOR_ACTIVE) continue;
1571 
1572     // -- Get active restriction type
1573     CeedCallBackend(CeedOperatorFieldGetElemRestriction(op_input_fields[i], &elem_rstr));
1574     CeedCallBackend(CeedElemRestrictionGetType(elem_rstr, &rstr_type));
1575     is_active_at_points = rstr_type == CEED_RESTRICTION_POINTS;
1576     if (!is_active_at_points) CeedCallBackend(CeedElemRestrictionGetElementSize(elem_rstr, &elem_size));
1577     else elem_size = max_num_points;
1578     CeedCallBackend(CeedElemRestrictionGetNumComponents(elem_rstr, &num_comp_active));
1579 
1580     e_vec_size = elem_size * num_comp_active;
1581     for (CeedInt s = 0; s < e_vec_size; s++) {
1582       bool         is_active_input = false;
1583       CeedEvalMode eval_mode;
1584       CeedVector   vec;
1585       CeedBasis    basis;
1586 
1587       CeedCallBackend(CeedOperatorFieldGetVector(op_input_fields[i], &vec));
1588       // Skip non-active input
1589       is_active_input = vec == CEED_VECTOR_ACTIVE;
1590       if (!is_active_input) continue;
1591 
1592       // Update unit vector
1593       if (s == 0) CeedCallBackend(CeedVectorSetValue(impl->e_vecs[i], 0.0));
1594       else CeedCallBackend(CeedVectorSetValueStrided(impl->e_vecs[i], s - 1, e_vec_size, 0.0));
1595       CeedCallBackend(CeedVectorSetValueStrided(impl->e_vecs[i], s, e_vec_size, 1.0));
1596 
1597       // Basis action
1598       CeedCallBackend(CeedQFunctionFieldGetEvalMode(qf_input_fields[i], &eval_mode));
1599       switch (eval_mode) {
1600         case CEED_EVAL_NONE:
1601           CeedCallBackend(CeedVectorSetArray(impl->q_vecs_in[i], CEED_MEM_DEVICE, CEED_USE_POINTER, e_data[i]));
1602           break;
1603         case CEED_EVAL_INTERP:
1604         case CEED_EVAL_GRAD:
1605         case CEED_EVAL_DIV:
1606         case CEED_EVAL_CURL:
1607           CeedCallBackend(CeedOperatorFieldGetBasis(op_input_fields[i], &basis));
1608           CeedCallBackend(CeedBasisApplyAtPoints(basis, num_elem, num_points, CEED_NOTRANSPOSE, eval_mode, impl->point_coords_elem, impl->e_vecs[i],
1609                                                  impl->q_vecs_in[i]));
1610           break;
1611         case CEED_EVAL_WEIGHT:
1612           break;  // No action
1613       }
1614 
1615       // Q function
1616       CeedCallBackend(CeedQFunctionApply(qf, num_elem * max_num_points, impl->q_vecs_in, impl->q_vecs_out));
1617 
1618       // Output basis apply if needed
1619       for (CeedInt j = 0; j < num_output_fields; j++) {
1620         bool                is_active_output = false;
1621         CeedInt             elem_size        = 0;
1622         CeedRestrictionType rstr_type;
1623         CeedEvalMode        eval_mode;
1624         CeedVector          vec;
1625         CeedElemRestriction elem_rstr;
1626         CeedBasis           basis;
1627 
1628         CeedCallBackend(CeedOperatorFieldGetVector(op_output_fields[j], &vec));
1629         // ---- Skip non-active output
1630         is_active_output = vec == CEED_VECTOR_ACTIVE;
1631         if (!is_active_output) continue;
1632 
1633         // ---- Check if elem size matches
1634         CeedCallBackend(CeedOperatorFieldGetElemRestriction(op_output_fields[j], &elem_rstr));
1635         CeedCallBackend(CeedElemRestrictionGetType(elem_rstr, &rstr_type));
1636         if (is_active_at_points && rstr_type != CEED_RESTRICTION_POINTS) continue;
1637         if (rstr_type == CEED_RESTRICTION_POINTS) {
1638           CeedCallBackend(CeedElemRestrictionGetMaxPointsInElement(elem_rstr, &elem_size));
1639         } else {
1640           CeedCallBackend(CeedElemRestrictionGetElementSize(elem_rstr, &elem_size));
1641         }
1642         {
1643           CeedInt num_comp = 0;
1644 
1645           CeedCallBackend(CeedElemRestrictionGetNumComponents(elem_rstr, &num_comp));
1646           if (e_vec_size != num_comp * elem_size) continue;
1647         }
1648 
1649         // Basis action
1650         CeedCallBackend(CeedQFunctionFieldGetEvalMode(qf_output_fields[j], &eval_mode));
1651         switch (eval_mode) {
1652           case CEED_EVAL_NONE:
1653             CeedCallBackend(CeedVectorRestoreArray(impl->e_vecs[j + impl->num_inputs], &e_data[j + num_input_fields]));
1654             break;
1655           case CEED_EVAL_INTERP:
1656           case CEED_EVAL_GRAD:
1657           case CEED_EVAL_DIV:
1658           case CEED_EVAL_CURL:
1659             CeedCallBackend(CeedOperatorFieldGetBasis(op_output_fields[j], &basis));
1660             CeedCallBackend(CeedBasisApplyAtPoints(basis, num_elem, num_points, CEED_TRANSPOSE, eval_mode, impl->point_coords_elem,
1661                                                    impl->q_vecs_out[j], impl->e_vecs[j + impl->num_inputs]));
1662             break;
1663           // LCOV_EXCL_START
1664           case CEED_EVAL_WEIGHT: {
1665             return CeedError(CeedOperatorReturnCeed(op), CEED_ERROR_BACKEND, "CEED_EVAL_WEIGHT cannot be an output evaluation mode");
1666             // LCOV_EXCL_STOP
1667           }
1668         }
1669 
1670         // Mask output e-vec
1671         CeedCallBackend(CeedVectorPointwiseMult(impl->e_vecs[j + impl->num_inputs], impl->e_vecs[i], impl->e_vecs[j + impl->num_inputs]));
1672 
1673         // Restrict
1674         CeedCallBackend(CeedOperatorFieldGetElemRestriction(op_output_fields[j], &elem_rstr));
1675         CeedCallBackend(CeedElemRestrictionApply(elem_rstr, CEED_TRANSPOSE, impl->e_vecs[j + impl->num_inputs], assembled, request));
1676 
1677         // Reset q_vec for
1678         if (eval_mode == CEED_EVAL_NONE) {
1679           CeedCallBackend(CeedVectorGetArrayWrite(impl->e_vecs[j + impl->num_inputs], CEED_MEM_DEVICE, &e_data[j + num_input_fields]));
1680           CeedCallBackend(CeedVectorSetArray(impl->q_vecs_out[j], CEED_MEM_DEVICE, CEED_USE_POINTER, e_data[j + num_input_fields]));
1681         }
1682       }
1683 
1684       // Reset vec
1685       if (s == e_vec_size - 1 && i != num_input_fields - 1) CeedCallBackend(CeedVectorSetValue(impl->q_vecs_in[i], 0.0));
1686     }
1687   }
1688 
1689   // Restore CEED_EVAL_NONE
1690   for (CeedInt i = 0; i < num_output_fields; i++) {
1691     CeedEvalMode eval_mode;
1692 
1693     // Get eval_mode
1694     CeedCallBackend(CeedQFunctionFieldGetEvalMode(qf_output_fields[i], &eval_mode));
1695 
1696     // Restore evec
1697     CeedCallBackend(CeedQFunctionFieldGetEvalMode(qf_output_fields[i], &eval_mode));
1698     if (eval_mode == CEED_EVAL_NONE) {
1699       CeedCallBackend(CeedVectorRestoreArray(impl->e_vecs[i + impl->num_inputs], &e_data[i + num_input_fields]));
1700     }
1701   }
1702 
1703   // Restore input arrays
1704   CeedCallBackend(CeedOperatorRestoreInputs_Cuda(num_input_fields, qf_input_fields, op_input_fields, true, e_data, impl));
1705   return CEED_ERROR_SUCCESS;
1706 }
1707 
1708 //------------------------------------------------------------------------------
1709 // Create operator
1710 //------------------------------------------------------------------------------
1711 int CeedOperatorCreate_Cuda(CeedOperator op) {
1712   Ceed               ceed;
1713   CeedOperator_Cuda *impl;
1714 
1715   CeedCallBackend(CeedOperatorGetCeed(op, &ceed));
1716   CeedCallBackend(CeedCalloc(1, &impl));
1717   CeedCallBackend(CeedOperatorSetData(op, impl));
1718 
1719   CeedCallBackend(CeedSetBackendFunction(ceed, "Operator", op, "LinearAssembleQFunction", CeedOperatorLinearAssembleQFunction_Cuda));
1720   CeedCallBackend(CeedSetBackendFunction(ceed, "Operator", op, "LinearAssembleQFunctionUpdate", CeedOperatorLinearAssembleQFunctionUpdate_Cuda));
1721   CeedCallBackend(CeedSetBackendFunction(ceed, "Operator", op, "LinearAssembleAddDiagonal", CeedOperatorLinearAssembleAddDiagonal_Cuda));
1722   CeedCallBackend(
1723       CeedSetBackendFunction(ceed, "Operator", op, "LinearAssembleAddPointBlockDiagonal", CeedOperatorLinearAssembleAddPointBlockDiagonal_Cuda));
1724   CeedCallBackend(CeedSetBackendFunction(ceed, "Operator", op, "LinearAssembleSingle", CeedSingleOperatorAssemble_Cuda));
1725   CeedCallBackend(CeedSetBackendFunction(ceed, "Operator", op, "ApplyAdd", CeedOperatorApplyAdd_Cuda));
1726   CeedCallBackend(CeedSetBackendFunction(ceed, "Operator", op, "Destroy", CeedOperatorDestroy_Cuda));
1727   return CEED_ERROR_SUCCESS;
1728 }
1729 
1730 //------------------------------------------------------------------------------
1731 // Create operator AtPoints
1732 //------------------------------------------------------------------------------
1733 int CeedOperatorCreateAtPoints_Cuda(CeedOperator op) {
1734   Ceed               ceed;
1735   CeedOperator_Cuda *impl;
1736 
1737   CeedCallBackend(CeedOperatorGetCeed(op, &ceed));
1738   CeedCallBackend(CeedCalloc(1, &impl));
1739   CeedCallBackend(CeedOperatorSetData(op, impl));
1740 
1741   CeedCallBackend(CeedSetBackendFunction(ceed, "Operator", op, "LinearAssembleQFunction", CeedOperatorLinearAssembleQFunctionAtPoints_Cuda));
1742   CeedCallBackend(CeedSetBackendFunction(ceed, "Operator", op, "LinearAssembleAddDiagonal", CeedOperatorLinearAssembleAddDiagonalAtPoints_Cuda));
1743   CeedCallBackend(CeedSetBackendFunction(ceed, "Operator", op, "ApplyAdd", CeedOperatorApplyAddAtPoints_Cuda));
1744   CeedCallBackend(CeedSetBackendFunction(ceed, "Operator", op, "Destroy", CeedOperatorDestroy_Cuda));
1745   return CEED_ERROR_SUCCESS;
1746 }
1747 
1748 //------------------------------------------------------------------------------
1749