xref: /libCEED/backends/cuda-ref/ceed-cuda-ref-operator.c (revision e64bb3f3ed2986a0c10dec3b47522d734c6e367d)
1 // Copyright (c) 2017-2022, 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   CeedCallBackend(CeedOperatorGetData(op, &impl));
27 
28   // Apply data
29   for (CeedInt i = 0; i < impl->numein + impl->numeout; i++) {
30     CeedCallBackend(CeedVectorDestroy(&impl->evecs[i]));
31   }
32   CeedCallBackend(CeedFree(&impl->evecs));
33 
34   for (CeedInt i = 0; i < impl->numein; i++) {
35     CeedCallBackend(CeedVectorDestroy(&impl->qvecsin[i]));
36   }
37   CeedCallBackend(CeedFree(&impl->qvecsin));
38 
39   for (CeedInt i = 0; i < impl->numeout; i++) {
40     CeedCallBackend(CeedVectorDestroy(&impl->qvecsout[i]));
41   }
42   CeedCallBackend(CeedFree(&impl->qvecsout));
43 
44   // QFunction assembly data
45   for (CeedInt i = 0; i < impl->qfnumactivein; i++) {
46     CeedCallBackend(CeedVectorDestroy(&impl->qfactivein[i]));
47   }
48   CeedCallBackend(CeedFree(&impl->qfactivein));
49 
50   // Diag data
51   if (impl->diag) {
52     Ceed ceed;
53     CeedCallBackend(CeedOperatorGetCeed(op, &ceed));
54     CeedCallCuda(ceed, cuModuleUnload(impl->diag->module));
55     CeedCallBackend(CeedFree(&impl->diag->h_emodein));
56     CeedCallBackend(CeedFree(&impl->diag->h_emodeout));
57     CeedCallCuda(ceed, cudaFree(impl->diag->d_emodein));
58     CeedCallCuda(ceed, cudaFree(impl->diag->d_emodeout));
59     CeedCallCuda(ceed, cudaFree(impl->diag->d_identity));
60     CeedCallCuda(ceed, cudaFree(impl->diag->d_interpin));
61     CeedCallCuda(ceed, cudaFree(impl->diag->d_interpout));
62     CeedCallCuda(ceed, cudaFree(impl->diag->d_gradin));
63     CeedCallCuda(ceed, cudaFree(impl->diag->d_gradout));
64     CeedCallBackend(CeedElemRestrictionDestroy(&impl->diag->pbdiagrstr));
65     CeedCallBackend(CeedVectorDestroy(&impl->diag->elemdiag));
66     CeedCallBackend(CeedVectorDestroy(&impl->diag->pbelemdiag));
67   }
68   CeedCallBackend(CeedFree(&impl->diag));
69 
70   if (impl->asmb) {
71     Ceed ceed;
72     CeedCallBackend(CeedOperatorGetCeed(op, &ceed));
73     CeedCallCuda(ceed, cuModuleUnload(impl->asmb->module));
74     CeedCallCuda(ceed, cudaFree(impl->asmb->d_B_in));
75     CeedCallCuda(ceed, cudaFree(impl->asmb->d_B_out));
76   }
77   CeedCallBackend(CeedFree(&impl->asmb));
78 
79   CeedCallBackend(CeedFree(&impl));
80   return CEED_ERROR_SUCCESS;
81 }
82 
83 //------------------------------------------------------------------------------
84 // Setup infields or outfields
85 //------------------------------------------------------------------------------
86 static int CeedOperatorSetupFields_Cuda(CeedQFunction qf, CeedOperator op, bool isinput, CeedVector *evecs, CeedVector *qvecs, CeedInt starte,
87                                         CeedInt numfields, CeedInt Q, CeedInt numelements) {
88   CeedInt  dim, size;
89   CeedSize q_size;
90   Ceed     ceed;
91   CeedCallBackend(CeedOperatorGetCeed(op, &ceed));
92   CeedBasis           basis;
93   CeedElemRestriction Erestrict;
94   CeedOperatorField  *opfields;
95   CeedQFunctionField *qffields;
96   CeedVector          fieldvec;
97   bool                strided;
98   bool                skiprestrict;
99 
100   if (isinput) {
101     CeedCallBackend(CeedOperatorGetFields(op, NULL, &opfields, NULL, NULL));
102     CeedCallBackend(CeedQFunctionGetFields(qf, NULL, &qffields, NULL, NULL));
103   } else {
104     CeedCallBackend(CeedOperatorGetFields(op, NULL, NULL, NULL, &opfields));
105     CeedCallBackend(CeedQFunctionGetFields(qf, NULL, NULL, NULL, &qffields));
106   }
107 
108   // Loop over fields
109   for (CeedInt i = 0; i < numfields; i++) {
110     CeedEvalMode emode;
111     CeedCallBackend(CeedQFunctionFieldGetEvalMode(qffields[i], &emode));
112 
113     strided      = false;
114     skiprestrict = false;
115     if (emode != CEED_EVAL_WEIGHT) {
116       CeedCallBackend(CeedOperatorFieldGetElemRestriction(opfields[i], &Erestrict));
117 
118       // Check whether this field can skip the element restriction:
119       // must be passive input, with emode NONE, and have a strided restriction with CEED_STRIDES_BACKEND.
120 
121       // First, check whether the field is input or output:
122       if (isinput) {
123         // Check for passive input:
124         CeedCallBackend(CeedOperatorFieldGetVector(opfields[i], &fieldvec));
125         if (fieldvec != CEED_VECTOR_ACTIVE) {
126           // Check emode
127           if (emode == CEED_EVAL_NONE) {
128             // Check for strided restriction
129             CeedCallBackend(CeedElemRestrictionIsStrided(Erestrict, &strided));
130             if (strided) {
131               // Check if vector is already in preferred backend ordering
132               CeedCallBackend(CeedElemRestrictionHasBackendStrides(Erestrict, &skiprestrict));
133             }
134           }
135         }
136       }
137       if (skiprestrict) {
138         // We do not need an E-Vector, but will use the input field vector's data directly in the operator application.
139         evecs[i + starte] = NULL;
140       } else {
141         CeedCallBackend(CeedElemRestrictionCreateVector(Erestrict, NULL, &evecs[i + starte]));
142       }
143     }
144 
145     switch (emode) {
146       case CEED_EVAL_NONE:
147         CeedCallBackend(CeedQFunctionFieldGetSize(qffields[i], &size));
148         q_size = (CeedSize)numelements * Q * size;
149         CeedCallBackend(CeedVectorCreate(ceed, q_size, &qvecs[i]));
150         break;
151       case CEED_EVAL_INTERP:
152         CeedCallBackend(CeedQFunctionFieldGetSize(qffields[i], &size));
153         q_size = (CeedSize)numelements * Q * size;
154         CeedCallBackend(CeedVectorCreate(ceed, q_size, &qvecs[i]));
155         break;
156       case CEED_EVAL_GRAD:
157         CeedCallBackend(CeedOperatorFieldGetBasis(opfields[i], &basis));
158         CeedCallBackend(CeedQFunctionFieldGetSize(qffields[i], &size));
159         CeedCallBackend(CeedBasisGetDimension(basis, &dim));
160         q_size = (CeedSize)numelements * Q * size;
161         CeedCallBackend(CeedVectorCreate(ceed, q_size, &qvecs[i]));
162         break;
163       case CEED_EVAL_WEIGHT:  // Only on input fields
164         CeedCallBackend(CeedOperatorFieldGetBasis(opfields[i], &basis));
165         q_size = (CeedSize)numelements * Q;
166         CeedCallBackend(CeedVectorCreate(ceed, q_size, &qvecs[i]));
167         CeedCallBackend(CeedBasisApply(basis, numelements, CEED_NOTRANSPOSE, CEED_EVAL_WEIGHT, CEED_VECTOR_NONE, qvecs[i]));
168         break;
169       case CEED_EVAL_DIV:
170         break;  // TODO: Not implemented
171       case CEED_EVAL_CURL:
172         break;  // TODO: Not implemented
173     }
174   }
175   return CEED_ERROR_SUCCESS;
176 }
177 
178 //------------------------------------------------------------------------------
179 // CeedOperator needs to connect all the named fields (be they active or passive) to the named inputs and outputs of its CeedQFunction.
180 //------------------------------------------------------------------------------
181 static int CeedOperatorSetup_Cuda(CeedOperator op) {
182   bool setupdone;
183   CeedCallBackend(CeedOperatorIsSetupDone(op, &setupdone));
184   if (setupdone) return CEED_ERROR_SUCCESS;
185   Ceed ceed;
186   CeedCallBackend(CeedOperatorGetCeed(op, &ceed));
187   CeedOperator_Cuda *impl;
188   CeedCallBackend(CeedOperatorGetData(op, &impl));
189   CeedQFunction qf;
190   CeedCallBackend(CeedOperatorGetQFunction(op, &qf));
191   CeedInt Q, numelements, numinputfields, numoutputfields;
192   CeedCallBackend(CeedOperatorGetNumQuadraturePoints(op, &Q));
193   CeedCallBackend(CeedOperatorGetNumElements(op, &numelements));
194   CeedOperatorField *opinputfields, *opoutputfields;
195   CeedCallBackend(CeedOperatorGetFields(op, &numinputfields, &opinputfields, &numoutputfields, &opoutputfields));
196   CeedQFunctionField *qfinputfields, *qfoutputfields;
197   CeedCallBackend(CeedQFunctionGetFields(qf, NULL, &qfinputfields, NULL, &qfoutputfields));
198 
199   // Allocate
200   CeedCallBackend(CeedCalloc(numinputfields + numoutputfields, &impl->evecs));
201 
202   CeedCallBackend(CeedCalloc(CEED_FIELD_MAX, &impl->qvecsin));
203   CeedCallBackend(CeedCalloc(CEED_FIELD_MAX, &impl->qvecsout));
204 
205   impl->numein  = numinputfields;
206   impl->numeout = numoutputfields;
207 
208   // Set up infield and outfield evecs and qvecs
209   // Infields
210   CeedCallBackend(CeedOperatorSetupFields_Cuda(qf, op, true, impl->evecs, impl->qvecsin, 0, numinputfields, Q, numelements));
211 
212   // Outfields
213   CeedCallBackend(CeedOperatorSetupFields_Cuda(qf, op, false, impl->evecs, impl->qvecsout, numinputfields, numoutputfields, Q, numelements));
214 
215   CeedCallBackend(CeedOperatorSetSetupDone(op));
216   return CEED_ERROR_SUCCESS;
217 }
218 
219 //------------------------------------------------------------------------------
220 // Setup Operator Inputs
221 //------------------------------------------------------------------------------
222 static inline int CeedOperatorSetupInputs_Cuda(CeedInt numinputfields, CeedQFunctionField *qfinputfields, CeedOperatorField *opinputfields,
223                                                CeedVector invec, const bool skipactive, CeedScalar *edata[2 * CEED_FIELD_MAX],
224                                                CeedOperator_Cuda *impl, CeedRequest *request) {
225   CeedEvalMode        emode;
226   CeedVector          vec;
227   CeedElemRestriction Erestrict;
228 
229   for (CeedInt i = 0; i < numinputfields; i++) {
230     // Get input vector
231     CeedCallBackend(CeedOperatorFieldGetVector(opinputfields[i], &vec));
232     if (vec == CEED_VECTOR_ACTIVE) {
233       if (skipactive) continue;
234       else vec = invec;
235     }
236 
237     CeedCallBackend(CeedQFunctionFieldGetEvalMode(qfinputfields[i], &emode));
238     if (emode == CEED_EVAL_WEIGHT) {  // Skip
239     } else {
240       // Get input vector
241       CeedCallBackend(CeedOperatorFieldGetVector(opinputfields[i], &vec));
242       // Get input element restriction
243       CeedCallBackend(CeedOperatorFieldGetElemRestriction(opinputfields[i], &Erestrict));
244       if (vec == CEED_VECTOR_ACTIVE) vec = invec;
245       // Restrict, if necessary
246       if (!impl->evecs[i]) {
247         // No restriction for this field; read data directly from vec.
248         CeedCallBackend(CeedVectorGetArrayRead(vec, CEED_MEM_DEVICE, (const CeedScalar **)&edata[i]));
249       } else {
250         CeedCallBackend(CeedElemRestrictionApply(Erestrict, CEED_NOTRANSPOSE, vec, impl->evecs[i], request));
251         // Get evec
252         CeedCallBackend(CeedVectorGetArrayRead(impl->evecs[i], CEED_MEM_DEVICE, (const CeedScalar **)&edata[i]));
253       }
254     }
255   }
256   return CEED_ERROR_SUCCESS;
257 }
258 
259 //------------------------------------------------------------------------------
260 // Input Basis Action
261 //------------------------------------------------------------------------------
262 static inline int CeedOperatorInputBasis_Cuda(CeedInt numelements, CeedQFunctionField *qfinputfields, CeedOperatorField *opinputfields,
263                                               CeedInt numinputfields, const bool skipactive, CeedScalar *edata[2 * CEED_FIELD_MAX],
264                                               CeedOperator_Cuda *impl) {
265   CeedInt             elemsize, size;
266   CeedElemRestriction Erestrict;
267   CeedEvalMode        emode;
268   CeedBasis           basis;
269 
270   for (CeedInt i = 0; i < numinputfields; i++) {
271     // Skip active input
272     if (skipactive) {
273       CeedVector vec;
274       CeedCallBackend(CeedOperatorFieldGetVector(opinputfields[i], &vec));
275       if (vec == CEED_VECTOR_ACTIVE) continue;
276     }
277     // Get elemsize, emode, size
278     CeedCallBackend(CeedOperatorFieldGetElemRestriction(opinputfields[i], &Erestrict));
279     CeedCallBackend(CeedElemRestrictionGetElementSize(Erestrict, &elemsize));
280     CeedCallBackend(CeedQFunctionFieldGetEvalMode(qfinputfields[i], &emode));
281     CeedCallBackend(CeedQFunctionFieldGetSize(qfinputfields[i], &size));
282     // Basis action
283     switch (emode) {
284       case CEED_EVAL_NONE:
285         CeedCallBackend(CeedVectorSetArray(impl->qvecsin[i], CEED_MEM_DEVICE, CEED_USE_POINTER, edata[i]));
286         break;
287       case CEED_EVAL_INTERP:
288         CeedCallBackend(CeedOperatorFieldGetBasis(opinputfields[i], &basis));
289         CeedCallBackend(CeedBasisApply(basis, numelements, CEED_NOTRANSPOSE, CEED_EVAL_INTERP, impl->evecs[i], impl->qvecsin[i]));
290         break;
291       case CEED_EVAL_GRAD:
292         CeedCallBackend(CeedOperatorFieldGetBasis(opinputfields[i], &basis));
293         CeedCallBackend(CeedBasisApply(basis, numelements, CEED_NOTRANSPOSE, CEED_EVAL_GRAD, impl->evecs[i], impl->qvecsin[i]));
294         break;
295       case CEED_EVAL_WEIGHT:
296         break;  // No action
297       case CEED_EVAL_DIV:
298         break;  // TODO: Not implemented
299       case CEED_EVAL_CURL:
300         break;  // TODO: Not implemented
301     }
302   }
303   return CEED_ERROR_SUCCESS;
304 }
305 
306 //------------------------------------------------------------------------------
307 // Restore Input Vectors
308 //------------------------------------------------------------------------------
309 static inline int CeedOperatorRestoreInputs_Cuda(CeedInt numinputfields, CeedQFunctionField *qfinputfields, CeedOperatorField *opinputfields,
310                                                  const bool skipactive, CeedScalar *edata[2 * CEED_FIELD_MAX], CeedOperator_Cuda *impl) {
311   CeedEvalMode emode;
312   CeedVector   vec;
313 
314   for (CeedInt i = 0; i < numinputfields; i++) {
315     // Skip active input
316     if (skipactive) {
317       CeedCallBackend(CeedOperatorFieldGetVector(opinputfields[i], &vec));
318       if (vec == CEED_VECTOR_ACTIVE) continue;
319     }
320     CeedCallBackend(CeedQFunctionFieldGetEvalMode(qfinputfields[i], &emode));
321     if (emode == CEED_EVAL_WEIGHT) {  // Skip
322     } else {
323       if (!impl->evecs[i]) {  // This was a skiprestrict case
324         CeedCallBackend(CeedOperatorFieldGetVector(opinputfields[i], &vec));
325         CeedCallBackend(CeedVectorRestoreArrayRead(vec, (const CeedScalar **)&edata[i]));
326       } else {
327         CeedCallBackend(CeedVectorRestoreArrayRead(impl->evecs[i], (const CeedScalar **)&edata[i]));
328       }
329     }
330   }
331   return CEED_ERROR_SUCCESS;
332 }
333 
334 //------------------------------------------------------------------------------
335 // Apply and add to output
336 //------------------------------------------------------------------------------
337 static int CeedOperatorApplyAdd_Cuda(CeedOperator op, CeedVector invec, CeedVector outvec, CeedRequest *request) {
338   CeedOperator_Cuda *impl;
339   CeedCallBackend(CeedOperatorGetData(op, &impl));
340   CeedQFunction qf;
341   CeedCallBackend(CeedOperatorGetQFunction(op, &qf));
342   CeedInt Q, numelements, elemsize, numinputfields, numoutputfields, size;
343   CeedCallBackend(CeedOperatorGetNumQuadraturePoints(op, &Q));
344   CeedCallBackend(CeedOperatorGetNumElements(op, &numelements));
345   CeedOperatorField *opinputfields, *opoutputfields;
346   CeedCallBackend(CeedOperatorGetFields(op, &numinputfields, &opinputfields, &numoutputfields, &opoutputfields));
347   CeedQFunctionField *qfinputfields, *qfoutputfields;
348   CeedCallBackend(CeedQFunctionGetFields(qf, NULL, &qfinputfields, NULL, &qfoutputfields));
349   CeedEvalMode        emode;
350   CeedVector          vec;
351   CeedBasis           basis;
352   CeedElemRestriction Erestrict;
353   CeedScalar         *edata[2 * CEED_FIELD_MAX] = {NULL};
354 
355   // Setup
356   CeedCallBackend(CeedOperatorSetup_Cuda(op));
357 
358   // Input Evecs and Restriction
359   CeedCallBackend(CeedOperatorSetupInputs_Cuda(numinputfields, qfinputfields, opinputfields, invec, false, edata, impl, request));
360 
361   // Input basis apply if needed
362   CeedCallBackend(CeedOperatorInputBasis_Cuda(numelements, qfinputfields, opinputfields, numinputfields, false, edata, impl));
363 
364   // Output pointers, as necessary
365   for (CeedInt i = 0; i < numoutputfields; i++) {
366     CeedCallBackend(CeedQFunctionFieldGetEvalMode(qfoutputfields[i], &emode));
367     if (emode == CEED_EVAL_NONE) {
368       // Set the output Q-Vector to use the E-Vector data directly.
369       CeedCallBackend(CeedVectorGetArrayWrite(impl->evecs[i + impl->numein], CEED_MEM_DEVICE, &edata[i + numinputfields]));
370       CeedCallBackend(CeedVectorSetArray(impl->qvecsout[i], CEED_MEM_DEVICE, CEED_USE_POINTER, edata[i + numinputfields]));
371     }
372   }
373 
374   // Q function
375   CeedCallBackend(CeedQFunctionApply(qf, numelements * Q, impl->qvecsin, impl->qvecsout));
376 
377   // Output basis apply if needed
378   for (CeedInt i = 0; i < numoutputfields; i++) {
379     // Get elemsize, emode, size
380     CeedCallBackend(CeedOperatorFieldGetElemRestriction(opoutputfields[i], &Erestrict));
381     CeedCallBackend(CeedElemRestrictionGetElementSize(Erestrict, &elemsize));
382     CeedCallBackend(CeedQFunctionFieldGetEvalMode(qfoutputfields[i], &emode));
383     CeedCallBackend(CeedQFunctionFieldGetSize(qfoutputfields[i], &size));
384     // Basis action
385     switch (emode) {
386       case CEED_EVAL_NONE:
387         break;
388       case CEED_EVAL_INTERP:
389         CeedCallBackend(CeedOperatorFieldGetBasis(opoutputfields[i], &basis));
390         CeedCallBackend(CeedBasisApply(basis, numelements, CEED_TRANSPOSE, CEED_EVAL_INTERP, impl->qvecsout[i], impl->evecs[i + impl->numein]));
391         break;
392       case CEED_EVAL_GRAD:
393         CeedCallBackend(CeedOperatorFieldGetBasis(opoutputfields[i], &basis));
394         CeedCallBackend(CeedBasisApply(basis, numelements, CEED_TRANSPOSE, CEED_EVAL_GRAD, impl->qvecsout[i], impl->evecs[i + impl->numein]));
395         break;
396       // LCOV_EXCL_START
397       case CEED_EVAL_WEIGHT: {
398         Ceed ceed;
399         CeedCallBackend(CeedOperatorGetCeed(op, &ceed));
400         return CeedError(ceed, CEED_ERROR_BACKEND, "CEED_EVAL_WEIGHT cannot be an output evaluation mode");
401         break;  // Should not occur
402       }
403       case CEED_EVAL_DIV:
404         break;  // TODO: Not implemented
405       case CEED_EVAL_CURL:
406         break;  // TODO: Not implemented
407                 // LCOV_EXCL_STOP
408     }
409   }
410 
411   // Output restriction
412   for (CeedInt i = 0; i < numoutputfields; i++) {
413     // Restore evec
414     CeedCallBackend(CeedQFunctionFieldGetEvalMode(qfoutputfields[i], &emode));
415     if (emode == CEED_EVAL_NONE) {
416       CeedCallBackend(CeedVectorRestoreArray(impl->evecs[i + impl->numein], &edata[i + numinputfields]));
417     }
418     // Get output vector
419     CeedCallBackend(CeedOperatorFieldGetVector(opoutputfields[i], &vec));
420     // Restrict
421     CeedCallBackend(CeedOperatorFieldGetElemRestriction(opoutputfields[i], &Erestrict));
422     // Active
423     if (vec == CEED_VECTOR_ACTIVE) vec = outvec;
424 
425     CeedCallBackend(CeedElemRestrictionApply(Erestrict, CEED_TRANSPOSE, impl->evecs[i + impl->numein], vec, request));
426   }
427 
428   // Restore input arrays
429   CeedCallBackend(CeedOperatorRestoreInputs_Cuda(numinputfields, qfinputfields, opinputfields, false, edata, impl));
430   return CEED_ERROR_SUCCESS;
431 }
432 
433 //------------------------------------------------------------------------------
434 // Core code for assembling linear QFunction
435 //------------------------------------------------------------------------------
436 static inline int CeedOperatorLinearAssembleQFunctionCore_Cuda(CeedOperator op, bool build_objects, CeedVector *assembled, CeedElemRestriction *rstr,
437                                                                CeedRequest *request) {
438   Ceed                ceed, ceedparent;
439   CeedOperator_Cuda  *impl;
440   CeedQFunction       qf;
441   CeedQFunctionField *qfinputfields, *qfoutputfields;
442   CeedOperatorField  *opinputfields, *opoutputfields;
443   CeedVector          vec, *activein;
444   CeedInt             numactivein, numactiveout, Q, numelements, numinputfields, numoutputfields, size;
445   CeedSize            q_size;
446   CeedScalar         *a, *tmp, *edata[2 * CEED_FIELD_MAX] = {NULL};
447   CeedCallBackend(CeedOperatorGetCeed(op, &ceed));
448   CeedCallBackend(CeedOperatorGetFallbackParentCeed(op, &ceedparent));
449   CeedCallBackend(CeedOperatorGetData(op, &impl));
450   activein    = impl->qfactivein;
451   numactivein = impl->qfnumactivein, numactiveout = impl->qfnumactiveout;
452   CeedCallBackend(CeedOperatorGetNumQuadraturePoints(op, &Q));
453   CeedCallBackend(CeedOperatorGetNumElements(op, &numelements));
454   CeedCallBackend(CeedOperatorGetQFunction(op, &qf));
455   CeedCallBackend(CeedQFunctionGetFields(qf, NULL, &qfinputfields, NULL, &qfoutputfields));
456   CeedCallBackend(CeedOperatorGetFields(op, &numinputfields, &opinputfields, &numoutputfields, &opoutputfields));
457 
458   // Setup
459   CeedCallBackend(CeedOperatorSetup_Cuda(op));
460 
461   // Check for identity
462   bool identityqf;
463   CeedCallBackend(CeedQFunctionIsIdentity(qf, &identityqf));
464   CeedCheck(!identityqf, ceed, CEED_ERROR_BACKEND, "Assembling identity QFunctions not supported");
465 
466   // Input Evecs and Restriction
467   CeedCallBackend(CeedOperatorSetupInputs_Cuda(numinputfields, qfinputfields, opinputfields, NULL, true, edata, impl, request));
468 
469   // Count number of active input fields
470   if (!numactivein) {
471     for (CeedInt i = 0; i < numinputfields; i++) {
472       // Get input vector
473       CeedCallBackend(CeedOperatorFieldGetVector(opinputfields[i], &vec));
474       // Check if active input
475       if (vec == CEED_VECTOR_ACTIVE) {
476         CeedCallBackend(CeedQFunctionFieldGetSize(qfinputfields[i], &size));
477         CeedCallBackend(CeedVectorSetValue(impl->qvecsin[i], 0.0));
478         CeedCallBackend(CeedVectorGetArray(impl->qvecsin[i], CEED_MEM_DEVICE, &tmp));
479         CeedCallBackend(CeedRealloc(numactivein + size, &activein));
480         for (CeedInt field = 0; field < size; field++) {
481           q_size = (CeedSize)Q * numelements;
482           CeedCallBackend(CeedVectorCreate(ceed, q_size, &activein[numactivein + field]));
483           CeedCallBackend(CeedVectorSetArray(activein[numactivein + field], CEED_MEM_DEVICE, CEED_USE_POINTER, &tmp[field * Q * numelements]));
484         }
485         numactivein += size;
486         CeedCallBackend(CeedVectorRestoreArray(impl->qvecsin[i], &tmp));
487       }
488     }
489     impl->qfnumactivein = numactivein;
490     impl->qfactivein    = activein;
491   }
492 
493   // Count number of active output fields
494   if (!numactiveout) {
495     for (CeedInt i = 0; i < numoutputfields; i++) {
496       // Get output vector
497       CeedCallBackend(CeedOperatorFieldGetVector(opoutputfields[i], &vec));
498       // Check if active output
499       if (vec == CEED_VECTOR_ACTIVE) {
500         CeedCallBackend(CeedQFunctionFieldGetSize(qfoutputfields[i], &size));
501         numactiveout += size;
502       }
503     }
504     impl->qfnumactiveout = numactiveout;
505   }
506 
507   // Check sizes
508   CeedCheck(numactivein > 0 && numactiveout > 0, ceed, CEED_ERROR_BACKEND, "Cannot assemble QFunction without active inputs and outputs");
509 
510   // Build objects if needed
511   if (build_objects) {
512     // Create output restriction
513     CeedInt strides[3] = {1, numelements * Q, Q}; /* *NOPAD* */
514     CeedCallBackend(CeedElemRestrictionCreateStrided(ceedparent, numelements, Q, numactivein * numactiveout,
515                                                      numactivein * numactiveout * numelements * Q, strides, rstr));
516     // Create assembled vector
517     CeedSize l_size = (CeedSize)numelements * Q * numactivein * numactiveout;
518     CeedCallBackend(CeedVectorCreate(ceedparent, l_size, assembled));
519   }
520   CeedCallBackend(CeedVectorSetValue(*assembled, 0.0));
521   CeedCallBackend(CeedVectorGetArray(*assembled, CEED_MEM_DEVICE, &a));
522 
523   // Input basis apply
524   CeedCallBackend(CeedOperatorInputBasis_Cuda(numelements, qfinputfields, opinputfields, numinputfields, true, edata, impl));
525 
526   // Assemble QFunction
527   for (CeedInt in = 0; in < numactivein; in++) {
528     // Set Inputs
529     CeedCallBackend(CeedVectorSetValue(activein[in], 1.0));
530     if (numactivein > 1) {
531       CeedCallBackend(CeedVectorSetValue(activein[(in + numactivein - 1) % numactivein], 0.0));
532     }
533     // Set Outputs
534     for (CeedInt out = 0; out < numoutputfields; out++) {
535       // Get output vector
536       CeedCallBackend(CeedOperatorFieldGetVector(opoutputfields[out], &vec));
537       // Check if active output
538       if (vec == CEED_VECTOR_ACTIVE) {
539         CeedCallBackend(CeedVectorSetArray(impl->qvecsout[out], CEED_MEM_DEVICE, CEED_USE_POINTER, a));
540         CeedCallBackend(CeedQFunctionFieldGetSize(qfoutputfields[out], &size));
541         a += size * Q * numelements;  // Advance the pointer by the size of the output
542       }
543     }
544     // Apply QFunction
545     CeedCallBackend(CeedQFunctionApply(qf, Q * numelements, impl->qvecsin, impl->qvecsout));
546   }
547 
548   // Un-set output Qvecs to prevent accidental overwrite of Assembled
549   for (CeedInt out = 0; out < numoutputfields; out++) {
550     // Get output vector
551     CeedCallBackend(CeedOperatorFieldGetVector(opoutputfields[out], &vec));
552     // Check if active output
553     if (vec == CEED_VECTOR_ACTIVE) {
554       CeedCallBackend(CeedVectorTakeArray(impl->qvecsout[out], CEED_MEM_DEVICE, NULL));
555     }
556   }
557 
558   // Restore input arrays
559   CeedCallBackend(CeedOperatorRestoreInputs_Cuda(numinputfields, qfinputfields, opinputfields, true, edata, impl));
560 
561   // Restore output
562   CeedCallBackend(CeedVectorRestoreArray(*assembled, &a));
563 
564   return CEED_ERROR_SUCCESS;
565 }
566 
567 //------------------------------------------------------------------------------
568 // Assemble Linear QFunction
569 //------------------------------------------------------------------------------
570 static int CeedOperatorLinearAssembleQFunction_Cuda(CeedOperator op, CeedVector *assembled, CeedElemRestriction *rstr, CeedRequest *request) {
571   return CeedOperatorLinearAssembleQFunctionCore_Cuda(op, true, assembled, rstr, request);
572 }
573 
574 //------------------------------------------------------------------------------
575 // Update Assembled Linear QFunction
576 //------------------------------------------------------------------------------
577 static int CeedOperatorLinearAssembleQFunctionUpdate_Cuda(CeedOperator op, CeedVector assembled, CeedElemRestriction rstr, CeedRequest *request) {
578   return CeedOperatorLinearAssembleQFunctionCore_Cuda(op, false, &assembled, &rstr, request);
579 }
580 
581 //------------------------------------------------------------------------------
582 // Create point block restriction
583 //------------------------------------------------------------------------------
584 static int CreatePBRestriction(CeedElemRestriction rstr, CeedElemRestriction *pbRstr) {
585   Ceed ceed;
586   CeedCallBackend(CeedElemRestrictionGetCeed(rstr, &ceed));
587   const CeedInt *offsets;
588   CeedCallBackend(CeedElemRestrictionGetOffsets(rstr, CEED_MEM_HOST, &offsets));
589 
590   // Expand offsets
591   CeedInt  nelem, ncomp, elemsize, compstride, *pbOffsets;
592   CeedSize l_size;
593   CeedCallBackend(CeedElemRestrictionGetNumElements(rstr, &nelem));
594   CeedCallBackend(CeedElemRestrictionGetNumComponents(rstr, &ncomp));
595   CeedCallBackend(CeedElemRestrictionGetElementSize(rstr, &elemsize));
596   CeedCallBackend(CeedElemRestrictionGetCompStride(rstr, &compstride));
597   CeedCallBackend(CeedElemRestrictionGetLVectorSize(rstr, &l_size));
598   CeedInt shift = ncomp;
599   if (compstride != 1) shift *= ncomp;
600   CeedCallBackend(CeedCalloc(nelem * elemsize, &pbOffsets));
601   for (CeedInt i = 0; i < nelem * elemsize; i++) {
602     pbOffsets[i] = offsets[i] * shift;
603   }
604 
605   // Create new restriction
606   CeedCallBackend(
607       CeedElemRestrictionCreate(ceed, nelem, elemsize, ncomp * ncomp, 1, l_size * ncomp, CEED_MEM_HOST, CEED_OWN_POINTER, pbOffsets, pbRstr));
608 
609   // Cleanup
610   CeedCallBackend(CeedElemRestrictionRestoreOffsets(rstr, &offsets));
611 
612   return CEED_ERROR_SUCCESS;
613 }
614 
615 //------------------------------------------------------------------------------
616 // Assemble diagonal setup
617 //------------------------------------------------------------------------------
618 static inline int CeedOperatorAssembleDiagonalSetup_Cuda(CeedOperator op, const bool pointBlock, CeedInt use_ceedsize_idx) {
619   Ceed ceed;
620   CeedCallBackend(CeedOperatorGetCeed(op, &ceed));
621   CeedQFunction qf;
622   CeedCallBackend(CeedOperatorGetQFunction(op, &qf));
623   CeedInt numinputfields, numoutputfields;
624   CeedCallBackend(CeedQFunctionGetNumArgs(qf, &numinputfields, &numoutputfields));
625 
626   // Determine active input basis
627   CeedOperatorField  *opfields;
628   CeedQFunctionField *qffields;
629   CeedCallBackend(CeedOperatorGetFields(op, NULL, &opfields, NULL, NULL));
630   CeedCallBackend(CeedQFunctionGetFields(qf, NULL, &qffields, NULL, NULL));
631   CeedInt             numemodein = 0, ncomp = 0, dim = 1;
632   CeedEvalMode       *emodein = NULL;
633   CeedBasis           basisin = NULL;
634   CeedElemRestriction rstrin  = NULL;
635   for (CeedInt i = 0; i < numinputfields; i++) {
636     CeedVector vec;
637     CeedCallBackend(CeedOperatorFieldGetVector(opfields[i], &vec));
638     if (vec == CEED_VECTOR_ACTIVE) {
639       CeedElemRestriction rstr;
640       CeedCallBackend(CeedOperatorFieldGetBasis(opfields[i], &basisin));
641       CeedCallBackend(CeedBasisGetNumComponents(basisin, &ncomp));
642       CeedCallBackend(CeedBasisGetDimension(basisin, &dim));
643       CeedCallBackend(CeedOperatorFieldGetElemRestriction(opfields[i], &rstr));
644       CeedCheck(!rstrin || rstrin == rstr, ceed, CEED_ERROR_BACKEND,
645                 "Backend does not implement multi-field non-composite operator diagonal assembly");
646       rstrin = rstr;
647       CeedEvalMode emode;
648       CeedCallBackend(CeedQFunctionFieldGetEvalMode(qffields[i], &emode));
649       switch (emode) {
650         case CEED_EVAL_NONE:
651         case CEED_EVAL_INTERP:
652           CeedCallBackend(CeedRealloc(numemodein + 1, &emodein));
653           emodein[numemodein] = emode;
654           numemodein += 1;
655           break;
656         case CEED_EVAL_GRAD:
657           CeedCallBackend(CeedRealloc(numemodein + dim, &emodein));
658           for (CeedInt d = 0; d < dim; d++) emodein[numemodein + d] = emode;
659           numemodein += dim;
660           break;
661         case CEED_EVAL_WEIGHT:
662         case CEED_EVAL_DIV:
663         case CEED_EVAL_CURL:
664           break;  // Caught by QF Assembly
665       }
666     }
667   }
668 
669   // Determine active output basis
670   CeedCallBackend(CeedOperatorGetFields(op, NULL, NULL, NULL, &opfields));
671   CeedCallBackend(CeedQFunctionGetFields(qf, NULL, NULL, NULL, &qffields));
672   CeedInt             numemodeout = 0;
673   CeedEvalMode       *emodeout    = NULL;
674   CeedBasis           basisout    = NULL;
675   CeedElemRestriction rstrout     = NULL;
676   for (CeedInt i = 0; i < numoutputfields; i++) {
677     CeedVector vec;
678     CeedCallBackend(CeedOperatorFieldGetVector(opfields[i], &vec));
679     if (vec == CEED_VECTOR_ACTIVE) {
680       CeedElemRestriction rstr;
681       CeedCallBackend(CeedOperatorFieldGetBasis(opfields[i], &basisout));
682       CeedCallBackend(CeedOperatorFieldGetElemRestriction(opfields[i], &rstr));
683       CeedCheck(!rstrout || rstrout == rstr, ceed, CEED_ERROR_BACKEND,
684                 "Backend does not implement multi-field non-composite operator diagonal assembly");
685       rstrout = rstr;
686       CeedEvalMode emode;
687       CeedCallBackend(CeedQFunctionFieldGetEvalMode(qffields[i], &emode));
688       switch (emode) {
689         case CEED_EVAL_NONE:
690         case CEED_EVAL_INTERP:
691           CeedCallBackend(CeedRealloc(numemodeout + 1, &emodeout));
692           emodeout[numemodeout] = emode;
693           numemodeout += 1;
694           break;
695         case CEED_EVAL_GRAD:
696           CeedCallBackend(CeedRealloc(numemodeout + dim, &emodeout));
697           for (CeedInt d = 0; d < dim; d++) emodeout[numemodeout + d] = emode;
698           numemodeout += dim;
699           break;
700         case CEED_EVAL_WEIGHT:
701         case CEED_EVAL_DIV:
702         case CEED_EVAL_CURL:
703           break;  // Caught by QF Assembly
704       }
705     }
706   }
707 
708   // Operator data struct
709   CeedOperator_Cuda *impl;
710   CeedCallBackend(CeedOperatorGetData(op, &impl));
711   CeedCallBackend(CeedCalloc(1, &impl->diag));
712   CeedOperatorDiag_Cuda *diag = impl->diag;
713   diag->basisin               = basisin;
714   diag->basisout              = basisout;
715   diag->h_emodein             = emodein;
716   diag->h_emodeout            = emodeout;
717   diag->numemodein            = numemodein;
718   diag->numemodeout           = numemodeout;
719 
720   // Assemble kernel
721   char *diagonal_kernel_path, *diagonal_kernel_source;
722   CeedCallBackend(CeedGetJitAbsolutePath(ceed, "ceed/jit-source/cuda/cuda-ref-operator-assemble-diagonal.h", &diagonal_kernel_path));
723   CeedDebug256(ceed, CEED_DEBUG_COLOR_SUCCESS, "----- Loading Diagonal Assembly Kernel Source -----\n");
724   CeedCallBackend(CeedLoadSourceToBuffer(ceed, diagonal_kernel_path, &diagonal_kernel_source));
725   CeedDebug256(ceed, CEED_DEBUG_COLOR_SUCCESS, "----- Loading Diagonal Assembly Source Complete! -----\n");
726   CeedInt nnodes, nqpts;
727   CeedCallBackend(CeedBasisGetNumNodes(basisin, &nnodes));
728   CeedCallBackend(CeedBasisGetNumQuadraturePoints(basisin, &nqpts));
729   diag->nnodes = nnodes;
730   CeedCallCuda(ceed, CeedCompile_Cuda(ceed, diagonal_kernel_source, &diag->module, 6, "NUMEMODEIN", numemodein, "NUMEMODEOUT", numemodeout, "NNODES",
731                                       nnodes, "NQPTS", nqpts, "NCOMP", ncomp, "CEEDSIZE", use_ceedsize_idx));
732   CeedCallCuda(ceed, CeedGetKernel_Cuda(ceed, diag->module, "linearDiagonal", &diag->linearDiagonal));
733   CeedCallCuda(ceed, CeedGetKernel_Cuda(ceed, diag->module, "linearPointBlockDiagonal", &diag->linearPointBlock));
734   CeedCallBackend(CeedFree(&diagonal_kernel_path));
735   CeedCallBackend(CeedFree(&diagonal_kernel_source));
736 
737   // Basis matrices
738   const CeedInt     qBytes = nqpts * sizeof(CeedScalar);
739   const CeedInt     iBytes = qBytes * nnodes;
740   const CeedInt     gBytes = qBytes * nnodes * dim;
741   const CeedInt     eBytes = sizeof(CeedEvalMode);
742   const CeedScalar *interpin, *interpout, *gradin, *gradout;
743 
744   // CEED_EVAL_NONE
745   CeedScalar *identity = NULL;
746   bool        evalNone = false;
747   for (CeedInt i = 0; i < numemodein; i++) evalNone = evalNone || (emodein[i] == CEED_EVAL_NONE);
748   for (CeedInt i = 0; i < numemodeout; i++) evalNone = evalNone || (emodeout[i] == CEED_EVAL_NONE);
749   if (evalNone) {
750     CeedCallBackend(CeedCalloc(nqpts * nnodes, &identity));
751     for (CeedInt i = 0; i < (nnodes < nqpts ? nnodes : nqpts); i++) identity[i * nnodes + i] = 1.0;
752     CeedCallCuda(ceed, cudaMalloc((void **)&diag->d_identity, iBytes));
753     CeedCallCuda(ceed, cudaMemcpy(diag->d_identity, identity, iBytes, cudaMemcpyHostToDevice));
754   }
755 
756   // CEED_EVAL_INTERP
757   CeedCallBackend(CeedBasisGetInterp(basisin, &interpin));
758   CeedCallCuda(ceed, cudaMalloc((void **)&diag->d_interpin, iBytes));
759   CeedCallCuda(ceed, cudaMemcpy(diag->d_interpin, interpin, iBytes, cudaMemcpyHostToDevice));
760   CeedCallBackend(CeedBasisGetInterp(basisout, &interpout));
761   CeedCallCuda(ceed, cudaMalloc((void **)&diag->d_interpout, iBytes));
762   CeedCallCuda(ceed, cudaMemcpy(diag->d_interpout, interpout, iBytes, cudaMemcpyHostToDevice));
763 
764   // CEED_EVAL_GRAD
765   CeedCallBackend(CeedBasisGetGrad(basisin, &gradin));
766   CeedCallCuda(ceed, cudaMalloc((void **)&diag->d_gradin, gBytes));
767   CeedCallCuda(ceed, cudaMemcpy(diag->d_gradin, gradin, gBytes, cudaMemcpyHostToDevice));
768   CeedCallBackend(CeedBasisGetGrad(basisout, &gradout));
769   CeedCallCuda(ceed, cudaMalloc((void **)&diag->d_gradout, gBytes));
770   CeedCallCuda(ceed, cudaMemcpy(diag->d_gradout, gradout, gBytes, cudaMemcpyHostToDevice));
771 
772   // Arrays of emodes
773   CeedCallCuda(ceed, cudaMalloc((void **)&diag->d_emodein, numemodein * eBytes));
774   CeedCallCuda(ceed, cudaMemcpy(diag->d_emodein, emodein, numemodein * eBytes, cudaMemcpyHostToDevice));
775   CeedCallCuda(ceed, cudaMalloc((void **)&diag->d_emodeout, numemodeout * eBytes));
776   CeedCallCuda(ceed, cudaMemcpy(diag->d_emodeout, emodeout, numemodeout * eBytes, cudaMemcpyHostToDevice));
777 
778   // Restriction
779   diag->diagrstr = rstrout;
780 
781   return CEED_ERROR_SUCCESS;
782 }
783 
784 //------------------------------------------------------------------------------
785 // Assemble diagonal common code
786 //------------------------------------------------------------------------------
787 static inline int CeedOperatorAssembleDiagonalCore_Cuda(CeedOperator op, CeedVector assembled, CeedRequest *request, const bool pointBlock) {
788   Ceed ceed;
789   CeedCallBackend(CeedOperatorGetCeed(op, &ceed));
790   CeedOperator_Cuda *impl;
791   CeedCallBackend(CeedOperatorGetData(op, &impl));
792 
793   // Assemble QFunction
794   CeedVector          assembledqf = NULL;
795   CeedElemRestriction rstr        = NULL;
796   CeedCallBackend(CeedOperatorLinearAssembleQFunctionBuildOrUpdate(op, &assembledqf, &rstr, request));
797   CeedCallBackend(CeedElemRestrictionDestroy(&rstr));
798 
799   CeedSize assembled_length = 0, assembledqf_length = 0;
800   CeedCallBackend(CeedVectorGetLength(assembled, &assembled_length));
801   CeedCallBackend(CeedVectorGetLength(assembledqf, &assembledqf_length));
802   CeedInt use_ceedsize_idx = 0;
803   if ((assembled_length > INT_MAX) || (assembledqf_length > INT_MAX)) use_ceedsize_idx = 1;
804 
805   // Setup
806   if (!impl->diag) CeedCallBackend(CeedOperatorAssembleDiagonalSetup_Cuda(op, pointBlock, use_ceedsize_idx));
807   CeedOperatorDiag_Cuda *diag = impl->diag;
808   assert(diag != NULL);
809 
810   // Restriction
811   if (pointBlock && !diag->pbdiagrstr) {
812     CeedElemRestriction pbdiagrstr;
813     CeedCallBackend(CreatePBRestriction(diag->diagrstr, &pbdiagrstr));
814     diag->pbdiagrstr = pbdiagrstr;
815   }
816   CeedElemRestriction diagrstr = pointBlock ? diag->pbdiagrstr : diag->diagrstr;
817 
818   // Create diagonal vector
819   CeedVector elemdiag = pointBlock ? diag->pbelemdiag : diag->elemdiag;
820   if (!elemdiag) {
821     CeedCallBackend(CeedElemRestrictionCreateVector(diagrstr, NULL, &elemdiag));
822     if (pointBlock) diag->pbelemdiag = elemdiag;
823     else diag->elemdiag = elemdiag;
824   }
825   CeedCallBackend(CeedVectorSetValue(elemdiag, 0.0));
826 
827   // Assemble element operator diagonals
828   CeedScalar       *elemdiagarray;
829   const CeedScalar *assembledqfarray;
830   CeedCallBackend(CeedVectorGetArray(elemdiag, CEED_MEM_DEVICE, &elemdiagarray));
831   CeedCallBackend(CeedVectorGetArrayRead(assembledqf, CEED_MEM_DEVICE, &assembledqfarray));
832   CeedInt nelem;
833   CeedCallBackend(CeedElemRestrictionGetNumElements(diagrstr, &nelem));
834 
835   // Compute the diagonal of B^T D B
836   int   elemsPerBlock = 1;
837   int   grid          = nelem / elemsPerBlock + ((nelem / elemsPerBlock * elemsPerBlock < nelem) ? 1 : 0);
838   void *args[]        = {(void *)&nelem,   &diag->d_identity, &diag->d_interpin, &diag->d_gradin,   &diag->d_interpout,
839                          &diag->d_gradout, &diag->d_emodein,  &diag->d_emodeout, &assembledqfarray, &elemdiagarray};
840   if (pointBlock) {
841     CeedCallBackend(CeedRunKernelDim_Cuda(ceed, diag->linearPointBlock, grid, diag->nnodes, 1, elemsPerBlock, args));
842   } else {
843     CeedCallBackend(CeedRunKernelDim_Cuda(ceed, diag->linearDiagonal, grid, diag->nnodes, 1, elemsPerBlock, args));
844   }
845 
846   // Restore arrays
847   CeedCallBackend(CeedVectorRestoreArray(elemdiag, &elemdiagarray));
848   CeedCallBackend(CeedVectorRestoreArrayRead(assembledqf, &assembledqfarray));
849 
850   // Assemble local operator diagonal
851   CeedCallBackend(CeedElemRestrictionApply(diagrstr, CEED_TRANSPOSE, elemdiag, assembled, request));
852 
853   // Cleanup
854   CeedCallBackend(CeedVectorDestroy(&assembledqf));
855 
856   return CEED_ERROR_SUCCESS;
857 }
858 
859 //------------------------------------------------------------------------------
860 // Assemble Linear Diagonal
861 //------------------------------------------------------------------------------
862 static int CeedOperatorLinearAssembleAddDiagonal_Cuda(CeedOperator op, CeedVector assembled, CeedRequest *request) {
863   CeedCallBackend(CeedOperatorAssembleDiagonalCore_Cuda(op, assembled, request, false));
864   return CEED_ERROR_SUCCESS;
865 }
866 
867 //------------------------------------------------------------------------------
868 // Assemble Linear Point Block Diagonal
869 //------------------------------------------------------------------------------
870 static int CeedOperatorLinearAssembleAddPointBlockDiagonal_Cuda(CeedOperator op, CeedVector assembled, CeedRequest *request) {
871   CeedCallBackend(CeedOperatorAssembleDiagonalCore_Cuda(op, assembled, request, true));
872   return CEED_ERROR_SUCCESS;
873 }
874 
875 //------------------------------------------------------------------------------
876 // Single operator assembly setup
877 //------------------------------------------------------------------------------
878 static int CeedSingleOperatorAssembleSetup_Cuda(CeedOperator op, CeedInt use_ceedsize_idx) {
879   Ceed ceed;
880   CeedCallBackend(CeedOperatorGetCeed(op, &ceed));
881   CeedOperator_Cuda *impl;
882   CeedCallBackend(CeedOperatorGetData(op, &impl));
883 
884   // Get intput and output fields
885   CeedInt            num_input_fields, num_output_fields;
886   CeedOperatorField *input_fields;
887   CeedOperatorField *output_fields;
888   CeedCallBackend(CeedOperatorGetFields(op, &num_input_fields, &input_fields, &num_output_fields, &output_fields));
889 
890   // Determine active input basis eval mode
891   CeedQFunction qf;
892   CeedCallBackend(CeedOperatorGetQFunction(op, &qf));
893   CeedQFunctionField *qf_fields;
894   CeedCallBackend(CeedQFunctionGetFields(qf, NULL, &qf_fields, NULL, NULL));
895   // Note that the kernel will treat each dimension of a gradient action separately;
896   // i.e., when an active input has a CEED_EVAL_GRAD mode, num_emode_in will increment by dim.
897   // However, for the purposes of loading the B matrices, it will be treated as one mode, and we will load/copy the entire gradient matrix at once, so
898   // num_B_in_mats_to_load will be incremented by 1.
899   CeedInt             num_emode_in = 0, dim = 1, num_B_in_mats_to_load = 0, size_B_in = 0;
900   CeedEvalMode       *eval_mode_in = NULL;  // will be of size num_B_in_mats_load
901   CeedBasis           basis_in     = NULL;
902   CeedInt             nqpts = 0, esize = 0;
903   CeedElemRestriction rstr_in = NULL;
904   for (CeedInt i = 0; i < num_input_fields; i++) {
905     CeedVector vec;
906     CeedCallBackend(CeedOperatorFieldGetVector(input_fields[i], &vec));
907     if (vec == CEED_VECTOR_ACTIVE) {
908       CeedCallBackend(CeedOperatorFieldGetBasis(input_fields[i], &basis_in));
909       CeedCallBackend(CeedBasisGetDimension(basis_in, &dim));
910       CeedCallBackend(CeedBasisGetNumQuadraturePoints(basis_in, &nqpts));
911       CeedCallBackend(CeedOperatorFieldGetElemRestriction(input_fields[i], &rstr_in));
912       CeedCallBackend(CeedElemRestrictionGetElementSize(rstr_in, &esize));
913       CeedEvalMode eval_mode;
914       CeedCallBackend(CeedQFunctionFieldGetEvalMode(qf_fields[i], &eval_mode));
915       if (eval_mode != CEED_EVAL_NONE) {
916         CeedCallBackend(CeedRealloc(num_B_in_mats_to_load + 1, &eval_mode_in));
917         eval_mode_in[num_B_in_mats_to_load] = eval_mode;
918         num_B_in_mats_to_load += 1;
919         if (eval_mode == CEED_EVAL_GRAD) {
920           num_emode_in += dim;
921           size_B_in += dim * esize * nqpts;
922         } else {
923           num_emode_in += 1;
924           size_B_in += esize * nqpts;
925         }
926       }
927     }
928   }
929 
930   // Determine active output basis; basis_out and rstr_out only used if same as input, TODO
931   CeedCallBackend(CeedQFunctionGetFields(qf, NULL, NULL, NULL, &qf_fields));
932   CeedInt             num_emode_out = 0, num_B_out_mats_to_load = 0, size_B_out = 0;
933   CeedEvalMode       *eval_mode_out = NULL;
934   CeedBasis           basis_out     = NULL;
935   CeedElemRestriction rstr_out      = NULL;
936   for (CeedInt i = 0; i < num_output_fields; i++) {
937     CeedVector vec;
938     CeedCallBackend(CeedOperatorFieldGetVector(output_fields[i], &vec));
939     if (vec == CEED_VECTOR_ACTIVE) {
940       CeedCallBackend(CeedOperatorFieldGetBasis(output_fields[i], &basis_out));
941       CeedCallBackend(CeedOperatorFieldGetElemRestriction(output_fields[i], &rstr_out));
942       CeedCheck(!rstr_out || rstr_out == rstr_in, ceed, CEED_ERROR_BACKEND, "Backend does not implement multi-field non-composite operator assembly");
943       CeedEvalMode eval_mode;
944       CeedCallBackend(CeedQFunctionFieldGetEvalMode(qf_fields[i], &eval_mode));
945       if (eval_mode != CEED_EVAL_NONE) {
946         CeedCallBackend(CeedRealloc(num_B_out_mats_to_load + 1, &eval_mode_out));
947         eval_mode_out[num_B_out_mats_to_load] = eval_mode;
948         num_B_out_mats_to_load += 1;
949         if (eval_mode == CEED_EVAL_GRAD) {
950           num_emode_out += dim;
951           size_B_out += dim * esize * nqpts;
952         } else {
953           num_emode_out += 1;
954           size_B_out += esize * nqpts;
955         }
956       }
957     }
958   }
959   CeedCheck(num_emode_in > 0 && num_emode_out > 0, ceed, CEED_ERROR_UNSUPPORTED, "Cannot assemble operator without inputs/outputs");
960 
961   CeedInt nelem, ncomp;
962   CeedCallBackend(CeedElemRestrictionGetNumElements(rstr_in, &nelem));
963   CeedCallBackend(CeedElemRestrictionGetNumComponents(rstr_in, &ncomp));
964 
965   CeedCallBackend(CeedCalloc(1, &impl->asmb));
966   CeedOperatorAssemble_Cuda *asmb = impl->asmb;
967   asmb->nelem                     = nelem;
968 
969   // Compile kernels
970   int elemsPerBlock     = 1;
971   asmb->elemsPerBlock   = elemsPerBlock;
972   CeedInt    block_size = esize * esize * elemsPerBlock;
973   Ceed_Cuda *cuda_data;
974   CeedCallBackend(CeedGetData(ceed, &cuda_data));
975   char *assembly_kernel_path, *assembly_kernel_source;
976   CeedCallBackend(CeedGetJitAbsolutePath(ceed, "ceed/jit-source/cuda/cuda-ref-operator-assemble.h", &assembly_kernel_path));
977   CeedDebug256(ceed, CEED_DEBUG_COLOR_SUCCESS, "----- Loading Assembly Kernel Source -----\n");
978   CeedCallBackend(CeedLoadSourceToBuffer(ceed, assembly_kernel_path, &assembly_kernel_source));
979   CeedDebug256(ceed, CEED_DEBUG_COLOR_SUCCESS, "----- Loading Assembly Source Complete! -----\n");
980   bool fallback = block_size > cuda_data->device_prop.maxThreadsPerBlock;
981   if (fallback) {
982     // Use fallback kernel with 1D threadblock
983     block_size         = esize * elemsPerBlock;
984     asmb->block_size_x = esize;
985     asmb->block_size_y = 1;
986   } else {  // Use kernel with 2D threadblock
987     asmb->block_size_x = esize;
988     asmb->block_size_y = esize;
989   }
990   CeedCallBackend(CeedCompile_Cuda(ceed, assembly_kernel_source, &asmb->module, 8, "NELEM", nelem, "NUMEMODEIN", num_emode_in, "NUMEMODEOUT",
991                                    num_emode_out, "NQPTS", nqpts, "NNODES", esize, "BLOCK_SIZE", block_size, "NCOMP", ncomp, "CEEDSIZE",
992                                    use_ceedsize_idx));
993   CeedCallBackend(CeedGetKernel_Cuda(ceed, asmb->module, fallback ? "linearAssembleFallback" : "linearAssemble", &asmb->linearAssemble));
994   CeedCallBackend(CeedFree(&assembly_kernel_path));
995   CeedCallBackend(CeedFree(&assembly_kernel_source));
996 
997   // Build 'full' B matrices (not 1D arrays used for tensor-product matrices)
998   const CeedScalar *interp_in, *grad_in;
999   CeedCallBackend(CeedBasisGetInterp(basis_in, &interp_in));
1000   CeedCallBackend(CeedBasisGetGrad(basis_in, &grad_in));
1001 
1002   // Load into B_in, in order that they will be used in eval_mode
1003   const CeedInt inBytes   = size_B_in * sizeof(CeedScalar);
1004   CeedInt       mat_start = 0;
1005   CeedCallCuda(ceed, cudaMalloc((void **)&asmb->d_B_in, inBytes));
1006   for (int i = 0; i < num_B_in_mats_to_load; i++) {
1007     CeedEvalMode eval_mode = eval_mode_in[i];
1008     if (eval_mode == CEED_EVAL_INTERP) {
1009       CeedCallCuda(ceed, cudaMemcpy(&asmb->d_B_in[mat_start], interp_in, esize * nqpts * sizeof(CeedScalar), cudaMemcpyHostToDevice));
1010       mat_start += esize * nqpts;
1011     } else if (eval_mode == CEED_EVAL_GRAD) {
1012       CeedCallCuda(ceed, cudaMemcpy(&asmb->d_B_in[mat_start], grad_in, dim * esize * nqpts * sizeof(CeedScalar), cudaMemcpyHostToDevice));
1013       mat_start += dim * esize * nqpts;
1014     }
1015   }
1016 
1017   const CeedScalar *interp_out, *grad_out;
1018   // Note that this function currently assumes 1 basis, so this should always be true
1019   // for now
1020   if (basis_out == basis_in) {
1021     interp_out = interp_in;
1022     grad_out   = grad_in;
1023   } else {
1024     CeedCallBackend(CeedBasisGetInterp(basis_out, &interp_out));
1025     CeedCallBackend(CeedBasisGetGrad(basis_out, &grad_out));
1026   }
1027 
1028   // Load into B_out, in order that they will be used in eval_mode
1029   const CeedInt outBytes = size_B_out * sizeof(CeedScalar);
1030   mat_start              = 0;
1031   CeedCallCuda(ceed, cudaMalloc((void **)&asmb->d_B_out, outBytes));
1032   for (int i = 0; i < num_B_out_mats_to_load; i++) {
1033     CeedEvalMode eval_mode = eval_mode_out[i];
1034     if (eval_mode == CEED_EVAL_INTERP) {
1035       CeedCallCuda(ceed, cudaMemcpy(&asmb->d_B_out[mat_start], interp_out, esize * nqpts * sizeof(CeedScalar), cudaMemcpyHostToDevice));
1036       mat_start += esize * nqpts;
1037     } else if (eval_mode == CEED_EVAL_GRAD) {
1038       CeedCallCuda(ceed, cudaMemcpy(&asmb->d_B_out[mat_start], grad_out, dim * esize * nqpts * sizeof(CeedScalar), cudaMemcpyHostToDevice));
1039       mat_start += dim * esize * nqpts;
1040     }
1041   }
1042   return CEED_ERROR_SUCCESS;
1043 }
1044 
1045 //------------------------------------------------------------------------------
1046 // Assemble matrix data for COO matrix of assembled operator.
1047 // The sparsity pattern is set by CeedOperatorLinearAssembleSymbolic.
1048 //
1049 // Note that this (and other assembly routines) currently assume only one active input restriction/basis per operator (could have multiple basis eval
1050 // modes).
1051 // TODO: allow multiple active input restrictions/basis objects
1052 //------------------------------------------------------------------------------
1053 static int CeedSingleOperatorAssemble_Cuda(CeedOperator op, CeedInt offset, CeedVector values) {
1054   Ceed ceed;
1055   CeedCallBackend(CeedOperatorGetCeed(op, &ceed));
1056   CeedOperator_Cuda *impl;
1057   CeedCallBackend(CeedOperatorGetData(op, &impl));
1058 
1059   // Assemble QFunction
1060   CeedVector          assembled_qf = NULL;
1061   CeedElemRestriction rstr_q       = NULL;
1062   CeedCallBackend(CeedOperatorLinearAssembleQFunctionBuildOrUpdate(op, &assembled_qf, &rstr_q, CEED_REQUEST_IMMEDIATE));
1063   CeedCallBackend(CeedElemRestrictionDestroy(&rstr_q));
1064   CeedScalar *values_array;
1065   CeedCallBackend(CeedVectorGetArray(values, CEED_MEM_DEVICE, &values_array));
1066   values_array += offset;
1067   const CeedScalar *qf_array;
1068   CeedCallBackend(CeedVectorGetArrayRead(assembled_qf, CEED_MEM_DEVICE, &qf_array));
1069 
1070   CeedSize values_length = 0, assembled_qf_length = 0;
1071   CeedCallBackend(CeedVectorGetLength(values, &values_length));
1072   CeedCallBackend(CeedVectorGetLength(assembled_qf, &assembled_qf_length));
1073   CeedInt use_ceedsize_idx = 0;
1074   if ((values_length > INT_MAX) || (assembled_qf_length > INT_MAX)) use_ceedsize_idx = 1;
1075   // Setup
1076   if (!impl->asmb) {
1077     CeedCallBackend(CeedSingleOperatorAssembleSetup_Cuda(op, use_ceedsize_idx));
1078     assert(impl->asmb != NULL);
1079   }
1080 
1081   // Compute B^T D B
1082   const CeedInt nelem         = impl->asmb->nelem;
1083   const CeedInt elemsPerBlock = impl->asmb->elemsPerBlock;
1084   const CeedInt grid          = nelem / elemsPerBlock + ((nelem / elemsPerBlock * elemsPerBlock < nelem) ? 1 : 0);
1085   void         *args[]        = {&impl->asmb->d_B_in, &impl->asmb->d_B_out, &qf_array, &values_array};
1086   CeedCallBackend(
1087       CeedRunKernelDim_Cuda(ceed, impl->asmb->linearAssemble, grid, impl->asmb->block_size_x, impl->asmb->block_size_y, elemsPerBlock, args));
1088 
1089   // Restore arrays
1090   CeedCallBackend(CeedVectorRestoreArray(values, &values_array));
1091   CeedCallBackend(CeedVectorRestoreArrayRead(assembled_qf, &qf_array));
1092 
1093   // Cleanup
1094   CeedCallBackend(CeedVectorDestroy(&assembled_qf));
1095 
1096   return CEED_ERROR_SUCCESS;
1097 }
1098 
1099 //------------------------------------------------------------------------------
1100 // Create operator
1101 //------------------------------------------------------------------------------
1102 int CeedOperatorCreate_Cuda(CeedOperator op) {
1103   Ceed ceed;
1104   CeedCallBackend(CeedOperatorGetCeed(op, &ceed));
1105   CeedOperator_Cuda *impl;
1106 
1107   CeedCallBackend(CeedCalloc(1, &impl));
1108   CeedCallBackend(CeedOperatorSetData(op, impl));
1109 
1110   CeedCallBackend(CeedSetBackendFunction(ceed, "Operator", op, "LinearAssembleQFunction", CeedOperatorLinearAssembleQFunction_Cuda));
1111   CeedCallBackend(CeedSetBackendFunction(ceed, "Operator", op, "LinearAssembleQFunctionUpdate", CeedOperatorLinearAssembleQFunctionUpdate_Cuda));
1112   CeedCallBackend(CeedSetBackendFunction(ceed, "Operator", op, "LinearAssembleAddDiagonal", CeedOperatorLinearAssembleAddDiagonal_Cuda));
1113   CeedCallBackend(
1114       CeedSetBackendFunction(ceed, "Operator", op, "LinearAssembleAddPointBlockDiagonal", CeedOperatorLinearAssembleAddPointBlockDiagonal_Cuda));
1115   CeedCallBackend(CeedSetBackendFunction(ceed, "Operator", op, "LinearAssembleSingle", CeedSingleOperatorAssemble_Cuda));
1116   CeedCallBackend(CeedSetBackendFunction(ceed, "Operator", op, "ApplyAdd", CeedOperatorApplyAdd_Cuda));
1117   CeedCallBackend(CeedSetBackendFunction(ceed, "Operator", op, "Destroy", CeedOperatorDestroy_Cuda));
1118   return CEED_ERROR_SUCCESS;
1119 }
1120 
1121 //------------------------------------------------------------------------------
1122