xref: /libCEED/backends/ref/ceed-ref-operator.c (revision 2c2ea1dbee80fceecd2c97f30b09f8c87820a53e)
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 <stdbool.h>
11 #include <stddef.h>
12 #include <stdint.h>
13 
14 #include "ceed-ref.h"
15 
16 //------------------------------------------------------------------------------
17 // Setup Input/Output Fields
18 //------------------------------------------------------------------------------
19 static int CeedOperatorSetupFields_Ref(CeedQFunction qf, CeedOperator op, bool is_input, CeedVector *e_vecs_full, CeedVector *e_vecs,
20                                        CeedVector *q_vecs, CeedInt start_e, CeedInt num_fields, CeedInt Q) {
21   CeedInt  num_comp, size, P;
22   CeedSize e_size, q_size;
23   Ceed     ceed;
24   CeedCallBackend(CeedOperatorGetCeed(op, &ceed));
25   CeedBasis           basis;
26   CeedElemRestriction elem_restr;
27   CeedOperatorField  *op_fields;
28   CeedQFunctionField *qf_fields;
29   if (is_input) {
30     CeedCallBackend(CeedOperatorGetFields(op, NULL, &op_fields, NULL, NULL));
31     CeedCallBackend(CeedQFunctionGetFields(qf, NULL, &qf_fields, NULL, NULL));
32   } else {
33     CeedCallBackend(CeedOperatorGetFields(op, NULL, NULL, NULL, &op_fields));
34     CeedCallBackend(CeedQFunctionGetFields(qf, NULL, NULL, NULL, &qf_fields));
35   }
36 
37   // Loop over fields
38   for (CeedInt i = 0; i < num_fields; i++) {
39     CeedEvalMode eval_mode;
40     CeedCallBackend(CeedQFunctionFieldGetEvalMode(qf_fields[i], &eval_mode));
41 
42     if (eval_mode != CEED_EVAL_WEIGHT) {
43       CeedCallBackend(CeedOperatorFieldGetElemRestriction(op_fields[i], &elem_restr));
44       CeedCallBackend(CeedElemRestrictionCreateVector(elem_restr, NULL, &e_vecs_full[i + start_e]));
45     }
46 
47     switch (eval_mode) {
48       case CEED_EVAL_NONE:
49         CeedCallBackend(CeedQFunctionFieldGetSize(qf_fields[i], &size));
50         q_size = (CeedSize)Q * size;
51         CeedCallBackend(CeedVectorCreate(ceed, q_size, &q_vecs[i]));
52         break;
53       case CEED_EVAL_INTERP:
54       case CEED_EVAL_GRAD:
55       case CEED_EVAL_DIV:
56       case CEED_EVAL_CURL:
57         CeedCallBackend(CeedOperatorFieldGetBasis(op_fields[i], &basis));
58         CeedCallBackend(CeedQFunctionFieldGetSize(qf_fields[i], &size));
59         CeedCallBackend(CeedBasisGetNumNodes(basis, &P));
60         CeedCallBackend(CeedBasisGetNumComponents(basis, &num_comp));
61         e_size = (CeedSize)P * num_comp;
62         CeedCallBackend(CeedVectorCreate(ceed, e_size, &e_vecs[i]));
63         q_size = (CeedSize)Q * size;
64         CeedCallBackend(CeedVectorCreate(ceed, q_size, &q_vecs[i]));
65         break;
66       case CEED_EVAL_WEIGHT:  // Only on input fields
67         CeedCallBackend(CeedOperatorFieldGetBasis(op_fields[i], &basis));
68         q_size = (CeedSize)Q;
69         CeedCallBackend(CeedVectorCreate(ceed, q_size, &q_vecs[i]));
70         CeedCallBackend(CeedBasisApply(basis, 1, CEED_NOTRANSPOSE, CEED_EVAL_WEIGHT, CEED_VECTOR_NONE, q_vecs[i]));
71         break;
72     }
73   }
74   return CEED_ERROR_SUCCESS;
75 }
76 
77 //------------------------------------------------------------------------------
78 // Setup Operator
79 //------------------------------------------------------------------------------/*
80 static int CeedOperatorSetup_Ref(CeedOperator op) {
81   bool is_setup_done;
82   CeedCallBackend(CeedOperatorIsSetupDone(op, &is_setup_done));
83   if (is_setup_done) return CEED_ERROR_SUCCESS;
84   Ceed ceed;
85   CeedCallBackend(CeedOperatorGetCeed(op, &ceed));
86   CeedOperator_Ref *impl;
87   CeedCallBackend(CeedOperatorGetData(op, &impl));
88   CeedQFunction qf;
89   CeedCallBackend(CeedOperatorGetQFunction(op, &qf));
90   CeedInt Q, num_input_fields, num_output_fields;
91   CeedCallBackend(CeedOperatorGetNumQuadraturePoints(op, &Q));
92   CeedCallBackend(CeedQFunctionIsIdentity(qf, &impl->is_identity_qf));
93   CeedOperatorField *op_input_fields, *op_output_fields;
94   CeedCallBackend(CeedOperatorGetFields(op, &num_input_fields, &op_input_fields, &num_output_fields, &op_output_fields));
95   CeedQFunctionField *qf_input_fields, *qf_output_fields;
96   CeedCallBackend(CeedQFunctionGetFields(qf, NULL, &qf_input_fields, NULL, &qf_output_fields));
97 
98   // Allocate
99   CeedCallBackend(CeedCalloc(num_input_fields + num_output_fields, &impl->e_vecs_full));
100 
101   CeedCallBackend(CeedCalloc(CEED_FIELD_MAX, &impl->input_states));
102   CeedCallBackend(CeedCalloc(CEED_FIELD_MAX, &impl->e_vecs_in));
103   CeedCallBackend(CeedCalloc(CEED_FIELD_MAX, &impl->e_vecs_out));
104   CeedCallBackend(CeedCalloc(CEED_FIELD_MAX, &impl->q_vecs_in));
105   CeedCallBackend(CeedCalloc(CEED_FIELD_MAX, &impl->q_vecs_out));
106 
107   impl->num_inputs  = num_input_fields;
108   impl->num_outputs = num_output_fields;
109 
110   // Set up infield and outfield e_vecs and q_vecs
111   // Infields
112   CeedCallBackend(CeedOperatorSetupFields_Ref(qf, op, true, impl->e_vecs_full, impl->e_vecs_in, impl->q_vecs_in, 0, num_input_fields, Q));
113   // Outfields
114   CeedCallBackend(
115       CeedOperatorSetupFields_Ref(qf, op, false, impl->e_vecs_full, impl->e_vecs_out, impl->q_vecs_out, num_input_fields, num_output_fields, Q));
116 
117   // Identity QFunctions
118   if (impl->is_identity_qf) {
119     CeedEvalMode        in_mode, out_mode;
120     CeedQFunctionField *in_fields, *out_fields;
121     CeedCallBackend(CeedQFunctionGetFields(qf, NULL, &in_fields, NULL, &out_fields));
122     CeedCallBackend(CeedQFunctionFieldGetEvalMode(in_fields[0], &in_mode));
123     CeedCallBackend(CeedQFunctionFieldGetEvalMode(out_fields[0], &out_mode));
124 
125     if (in_mode == CEED_EVAL_NONE && out_mode == CEED_EVAL_NONE) {
126       impl->is_identity_restr_op = true;
127     } else {
128       CeedCallBackend(CeedVectorDestroy(&impl->q_vecs_out[0]));
129       impl->q_vecs_out[0] = impl->q_vecs_in[0];
130       CeedCallBackend(CeedVectorAddReference(impl->q_vecs_in[0]));
131     }
132   }
133 
134   CeedCallBackend(CeedOperatorSetSetupDone(op));
135 
136   return CEED_ERROR_SUCCESS;
137 }
138 
139 //------------------------------------------------------------------------------
140 // Setup Operator Inputs
141 //------------------------------------------------------------------------------
142 static inline int CeedOperatorSetupInputs_Ref(CeedInt num_input_fields, CeedQFunctionField *qf_input_fields, CeedOperatorField *op_input_fields,
143                                               CeedVector in_vec, const bool skip_active, CeedScalar *e_data_full[2 * CEED_FIELD_MAX],
144                                               CeedOperator_Ref *impl, CeedRequest *request) {
145   CeedEvalMode        eval_mode;
146   CeedVector          vec;
147   CeedElemRestriction elem_restr;
148   uint64_t            state;
149 
150   for (CeedInt i = 0; i < num_input_fields; i++) {
151     // Get input vector
152     CeedCallBackend(CeedOperatorFieldGetVector(op_input_fields[i], &vec));
153     if (vec == CEED_VECTOR_ACTIVE) {
154       if (skip_active) continue;
155       else vec = in_vec;
156     }
157 
158     CeedCallBackend(CeedQFunctionFieldGetEvalMode(qf_input_fields[i], &eval_mode));
159     // Restrict and Evec
160     if (eval_mode == CEED_EVAL_WEIGHT) {  // Skip
161     } else {
162       // Restrict
163       CeedCallBackend(CeedVectorGetState(vec, &state));
164       // Skip restriction if input is unchanged
165       if (state != impl->input_states[i] || vec == in_vec) {
166         CeedCallBackend(CeedOperatorFieldGetElemRestriction(op_input_fields[i], &elem_restr));
167         CeedCallBackend(CeedElemRestrictionApply(elem_restr, CEED_NOTRANSPOSE, vec, impl->e_vecs_full[i], request));
168         impl->input_states[i] = state;
169       }
170       // Get evec
171       CeedCallBackend(CeedVectorGetArrayRead(impl->e_vecs_full[i], CEED_MEM_HOST, (const CeedScalar **)&e_data_full[i]));
172     }
173   }
174   return CEED_ERROR_SUCCESS;
175 }
176 
177 //------------------------------------------------------------------------------
178 // Input Basis Action
179 //------------------------------------------------------------------------------
180 static inline int CeedOperatorInputBasis_Ref(CeedInt e, CeedInt Q, CeedQFunctionField *qf_input_fields, CeedOperatorField *op_input_fields,
181                                              CeedInt num_input_fields, const bool skip_active, CeedScalar *e_data_full[2 * CEED_FIELD_MAX],
182                                              CeedOperator_Ref *impl) {
183   CeedInt             elem_size, size, num_comp;
184   CeedElemRestriction elem_restr;
185   CeedEvalMode        eval_mode;
186   CeedBasis           basis;
187 
188   for (CeedInt i = 0; i < num_input_fields; i++) {
189     // Skip active input
190     if (skip_active) {
191       CeedVector vec;
192       CeedCallBackend(CeedOperatorFieldGetVector(op_input_fields[i], &vec));
193       if (vec == CEED_VECTOR_ACTIVE) continue;
194     }
195     // Get elem_size, eval_mode, size
196     CeedCallBackend(CeedOperatorFieldGetElemRestriction(op_input_fields[i], &elem_restr));
197     CeedCallBackend(CeedElemRestrictionGetElementSize(elem_restr, &elem_size));
198     CeedCallBackend(CeedQFunctionFieldGetEvalMode(qf_input_fields[i], &eval_mode));
199     CeedCallBackend(CeedQFunctionFieldGetSize(qf_input_fields[i], &size));
200     // Basis action
201     switch (eval_mode) {
202       case CEED_EVAL_NONE:
203         CeedCallBackend(CeedVectorSetArray(impl->q_vecs_in[i], CEED_MEM_HOST, CEED_USE_POINTER, &e_data_full[i][e * Q * size]));
204         break;
205       case CEED_EVAL_INTERP:
206       case CEED_EVAL_GRAD:
207       case CEED_EVAL_DIV:
208       case CEED_EVAL_CURL:
209         CeedCallBackend(CeedOperatorFieldGetBasis(op_input_fields[i], &basis));
210         CeedCallBackend(CeedBasisGetNumComponents(basis, &num_comp));
211         CeedCallBackend(CeedVectorSetArray(impl->e_vecs_in[i], CEED_MEM_HOST, CEED_USE_POINTER, &e_data_full[i][e * elem_size * num_comp]));
212         CeedCallBackend(CeedBasisApply(basis, 1, CEED_NOTRANSPOSE, eval_mode, impl->e_vecs_in[i], impl->q_vecs_in[i]));
213         break;
214       case CEED_EVAL_WEIGHT:
215         break;  // No action
216     }
217   }
218   return CEED_ERROR_SUCCESS;
219 }
220 
221 //------------------------------------------------------------------------------
222 // Output Basis Action
223 //------------------------------------------------------------------------------
224 static inline int CeedOperatorOutputBasis_Ref(CeedInt e, CeedInt Q, CeedQFunctionField *qf_output_fields, CeedOperatorField *op_output_fields,
225                                               CeedInt num_input_fields, CeedInt num_output_fields, CeedOperator op,
226                                               CeedScalar *e_data_full[2 * CEED_FIELD_MAX], CeedOperator_Ref *impl) {
227   CeedInt             elem_size, num_comp;
228   CeedElemRestriction elem_restr;
229   CeedEvalMode        eval_mode;
230   CeedBasis           basis;
231 
232   for (CeedInt i = 0; i < num_output_fields; i++) {
233     // Get elem_size, eval_mode
234     CeedCallBackend(CeedOperatorFieldGetElemRestriction(op_output_fields[i], &elem_restr));
235     CeedCallBackend(CeedElemRestrictionGetElementSize(elem_restr, &elem_size));
236     CeedCallBackend(CeedQFunctionFieldGetEvalMode(qf_output_fields[i], &eval_mode));
237     // Basis action
238     switch (eval_mode) {
239       case CEED_EVAL_NONE:
240         break;  // No action
241       case CEED_EVAL_INTERP:
242       case CEED_EVAL_GRAD:
243       case CEED_EVAL_DIV:
244       case CEED_EVAL_CURL:
245         CeedCallBackend(CeedOperatorFieldGetBasis(op_output_fields[i], &basis));
246         CeedCallBackend(CeedBasisGetNumComponents(basis, &num_comp));
247         CeedCallBackend(
248             CeedVectorSetArray(impl->e_vecs_out[i], CEED_MEM_HOST, CEED_USE_POINTER, &e_data_full[i + num_input_fields][e * elem_size * num_comp]));
249         CeedCallBackend(CeedBasisApply(basis, 1, CEED_TRANSPOSE, eval_mode, impl->q_vecs_out[i], impl->e_vecs_out[i]));
250         break;
251       // LCOV_EXCL_START
252       case CEED_EVAL_WEIGHT: {
253         Ceed ceed;
254         CeedCallBackend(CeedOperatorGetCeed(op, &ceed));
255         return CeedError(ceed, CEED_ERROR_BACKEND,
256                          "CEED_EVAL_WEIGHT cannot be an output "
257                          "evaluation mode");
258         // LCOV_EXCL_STOP
259       }
260     }
261   }
262   return CEED_ERROR_SUCCESS;
263 }
264 
265 //------------------------------------------------------------------------------
266 // Restore Input Vectors
267 //------------------------------------------------------------------------------
268 static inline int CeedOperatorRestoreInputs_Ref(CeedInt num_input_fields, CeedQFunctionField *qf_input_fields, CeedOperatorField *op_input_fields,
269                                                 const bool skip_active, CeedScalar *e_data_full[2 * CEED_FIELD_MAX], CeedOperator_Ref *impl) {
270   CeedEvalMode eval_mode;
271 
272   for (CeedInt i = 0; i < num_input_fields; i++) {
273     // Skip active inputs
274     if (skip_active) {
275       CeedVector vec;
276       CeedCallBackend(CeedOperatorFieldGetVector(op_input_fields[i], &vec));
277       if (vec == CEED_VECTOR_ACTIVE) continue;
278     }
279     // Restore input
280     CeedCallBackend(CeedQFunctionFieldGetEvalMode(qf_input_fields[i], &eval_mode));
281     if (eval_mode == CEED_EVAL_WEIGHT) {  // Skip
282     } else {
283       CeedCallBackend(CeedVectorRestoreArrayRead(impl->e_vecs_full[i], (const CeedScalar **)&e_data_full[i]));
284     }
285   }
286   return CEED_ERROR_SUCCESS;
287 }
288 
289 //------------------------------------------------------------------------------
290 // Operator Apply
291 //------------------------------------------------------------------------------
292 static int CeedOperatorApplyAdd_Ref(CeedOperator op, CeedVector in_vec, CeedVector out_vec, CeedRequest *request) {
293   CeedOperator_Ref *impl;
294   CeedCallBackend(CeedOperatorGetData(op, &impl));
295   CeedQFunction qf;
296   CeedCallBackend(CeedOperatorGetQFunction(op, &qf));
297   CeedInt Q, num_elem, num_input_fields, num_output_fields, size;
298   CeedCallBackend(CeedOperatorGetNumQuadraturePoints(op, &Q));
299   CeedCallBackend(CeedOperatorGetNumElements(op, &num_elem));
300   CeedOperatorField *op_input_fields, *op_output_fields;
301   CeedCallBackend(CeedOperatorGetFields(op, &num_input_fields, &op_input_fields, &num_output_fields, &op_output_fields));
302   CeedQFunctionField *qf_input_fields, *qf_output_fields;
303   CeedCallBackend(CeedQFunctionGetFields(qf, NULL, &qf_input_fields, NULL, &qf_output_fields));
304   CeedEvalMode        eval_mode;
305   CeedVector          vec;
306   CeedElemRestriction elem_restr;
307   CeedScalar         *e_data_full[2 * CEED_FIELD_MAX] = {0};
308 
309   // Setup
310   CeedCallBackend(CeedOperatorSetup_Ref(op));
311 
312   // Restriction only operator
313   if (impl->is_identity_restr_op) {
314     CeedCallBackend(CeedOperatorFieldGetElemRestriction(op_input_fields[0], &elem_restr));
315     CeedCallBackend(CeedElemRestrictionApply(elem_restr, CEED_NOTRANSPOSE, in_vec, impl->e_vecs_full[0], request));
316     CeedCallBackend(CeedOperatorFieldGetElemRestriction(op_output_fields[0], &elem_restr));
317     CeedCallBackend(CeedElemRestrictionApply(elem_restr, CEED_TRANSPOSE, impl->e_vecs_full[0], out_vec, request));
318     return CEED_ERROR_SUCCESS;
319   }
320 
321   // Input Evecs and Restriction
322   CeedCallBackend(CeedOperatorSetupInputs_Ref(num_input_fields, qf_input_fields, op_input_fields, in_vec, false, e_data_full, impl, request));
323 
324   // Output Evecs
325   for (CeedInt i = 0; i < num_output_fields; i++) {
326     CeedCallBackend(CeedVectorGetArrayWrite(impl->e_vecs_full[i + impl->num_inputs], CEED_MEM_HOST, &e_data_full[i + num_input_fields]));
327   }
328 
329   // Loop through elements
330   for (CeedInt e = 0; e < num_elem; e++) {
331     // Output pointers
332     for (CeedInt i = 0; i < num_output_fields; i++) {
333       CeedCallBackend(CeedQFunctionFieldGetEvalMode(qf_output_fields[i], &eval_mode));
334       if (eval_mode == CEED_EVAL_NONE) {
335         CeedCallBackend(CeedQFunctionFieldGetSize(qf_output_fields[i], &size));
336         CeedCallBackend(CeedVectorSetArray(impl->q_vecs_out[i], CEED_MEM_HOST, CEED_USE_POINTER, &e_data_full[i + num_input_fields][e * Q * size]));
337       }
338     }
339 
340     // Input basis apply
341     CeedCallBackend(CeedOperatorInputBasis_Ref(e, Q, qf_input_fields, op_input_fields, num_input_fields, false, e_data_full, impl));
342 
343     // Q function
344     if (!impl->is_identity_qf) {
345       CeedCallBackend(CeedQFunctionApply(qf, Q, impl->q_vecs_in, impl->q_vecs_out));
346     }
347 
348     // Output basis apply
349     CeedCallBackend(
350         CeedOperatorOutputBasis_Ref(e, Q, qf_output_fields, op_output_fields, num_input_fields, num_output_fields, op, e_data_full, impl));
351   }
352 
353   // Output restriction
354   for (CeedInt i = 0; i < num_output_fields; i++) {
355     // Restore Evec
356     CeedCallBackend(CeedVectorRestoreArray(impl->e_vecs_full[i + impl->num_inputs], &e_data_full[i + num_input_fields]));
357     // Get output vector
358     CeedCallBackend(CeedOperatorFieldGetVector(op_output_fields[i], &vec));
359     // Active
360     if (vec == CEED_VECTOR_ACTIVE) vec = out_vec;
361     // Restrict
362     CeedCallBackend(CeedOperatorFieldGetElemRestriction(op_output_fields[i], &elem_restr));
363     CeedCallBackend(CeedElemRestrictionApply(elem_restr, CEED_TRANSPOSE, impl->e_vecs_full[i + impl->num_inputs], vec, request));
364   }
365 
366   // Restore input arrays
367   CeedCallBackend(CeedOperatorRestoreInputs_Ref(num_input_fields, qf_input_fields, op_input_fields, false, e_data_full, impl));
368 
369   return CEED_ERROR_SUCCESS;
370 }
371 
372 //------------------------------------------------------------------------------
373 // Core code for assembling linear QFunction
374 //------------------------------------------------------------------------------
375 static inline int CeedOperatorLinearAssembleQFunctionCore_Ref(CeedOperator op, bool build_objects, CeedVector *assembled, CeedElemRestriction *rstr,
376                                                               CeedRequest *request) {
377   CeedOperator_Ref *impl;
378   CeedCallBackend(CeedOperatorGetData(op, &impl));
379   CeedQFunction qf;
380   CeedCallBackend(CeedOperatorGetQFunction(op, &qf));
381   CeedInt  Q, num_elem, num_input_fields, num_output_fields, size;
382   CeedSize q_size;
383   CeedCallBackend(CeedOperatorGetNumQuadraturePoints(op, &Q));
384   CeedCallBackend(CeedOperatorGetNumElements(op, &num_elem));
385   CeedOperatorField *op_input_fields, *op_output_fields;
386   CeedCallBackend(CeedOperatorGetFields(op, &num_input_fields, &op_input_fields, &num_output_fields, &op_output_fields));
387   CeedQFunctionField *qf_input_fields, *qf_output_fields;
388   CeedCallBackend(CeedQFunctionGetFields(qf, NULL, &qf_input_fields, NULL, &qf_output_fields));
389   CeedVector  vec;
390   CeedInt     num_active_in = impl->num_active_in, num_active_out = impl->num_active_out;
391   CeedVector *active_in = impl->qf_active_in;
392   CeedScalar *a, *tmp;
393   Ceed        ceed, ceed_parent;
394   CeedCallBackend(CeedOperatorGetCeed(op, &ceed));
395   CeedCallBackend(CeedGetOperatorFallbackParentCeed(ceed, &ceed_parent));
396   ceed_parent                                 = ceed_parent ? ceed_parent : ceed;
397   CeedScalar *e_data_full[2 * CEED_FIELD_MAX] = {0};
398 
399   // Setup
400   CeedCallBackend(CeedOperatorSetup_Ref(op));
401 
402   // Check for identity
403   if (impl->is_identity_qf) {
404     // LCOV_EXCL_START
405     return CeedError(ceed, CEED_ERROR_BACKEND, "Assembling identity QFunctions not supported");
406     // LCOV_EXCL_STOP
407   }
408 
409   // Input Evecs and Restriction
410   CeedCallBackend(CeedOperatorSetupInputs_Ref(num_input_fields, qf_input_fields, op_input_fields, NULL, true, e_data_full, impl, request));
411 
412   // Count number of active input fields
413   if (!num_active_in) {
414     for (CeedInt i = 0; i < num_input_fields; i++) {
415       // Get input vector
416       CeedCallBackend(CeedOperatorFieldGetVector(op_input_fields[i], &vec));
417       // Check if active input
418       if (vec == CEED_VECTOR_ACTIVE) {
419         CeedCallBackend(CeedQFunctionFieldGetSize(qf_input_fields[i], &size));
420         CeedCallBackend(CeedVectorSetValue(impl->q_vecs_in[i], 0.0));
421         CeedCallBackend(CeedVectorGetArray(impl->q_vecs_in[i], CEED_MEM_HOST, &tmp));
422         CeedCallBackend(CeedRealloc(num_active_in + size, &active_in));
423         for (CeedInt field = 0; field < size; field++) {
424           q_size = (CeedSize)Q;
425           CeedCallBackend(CeedVectorCreate(ceed, q_size, &active_in[num_active_in + field]));
426           CeedCallBackend(CeedVectorSetArray(active_in[num_active_in + field], CEED_MEM_HOST, CEED_USE_POINTER, &tmp[field * Q]));
427         }
428         num_active_in += size;
429         CeedCallBackend(CeedVectorRestoreArray(impl->q_vecs_in[i], &tmp));
430       }
431     }
432     impl->num_active_in = num_active_in;
433     impl->qf_active_in  = active_in;
434   }
435 
436   // Count number of active output fields
437   if (!num_active_out) {
438     for (CeedInt i = 0; i < num_output_fields; i++) {
439       // Get output vector
440       CeedCallBackend(CeedOperatorFieldGetVector(op_output_fields[i], &vec));
441       // Check if active output
442       if (vec == CEED_VECTOR_ACTIVE) {
443         CeedCallBackend(CeedQFunctionFieldGetSize(qf_output_fields[i], &size));
444         num_active_out += size;
445       }
446     }
447     impl->num_active_out = num_active_out;
448   }
449 
450   // Check sizes
451   if (!num_active_in || !num_active_out) {
452     // LCOV_EXCL_START
453     return CeedError(ceed, CEED_ERROR_BACKEND, "Cannot assemble QFunction without active inputs and outputs");
454     // LCOV_EXCL_STOP
455   }
456 
457   // Build objects if needed
458   if (build_objects) {
459     // Create output restriction
460     CeedInt strides[3] = {1, Q, num_active_in * num_active_out * Q}; /* *NOPAD* */
461     CeedCallBackend(CeedElemRestrictionCreateStrided(ceed_parent, num_elem, Q, num_active_in * num_active_out,
462                                                      num_active_in * num_active_out * num_elem * Q, strides, rstr));
463     // Create assembled vector
464     CeedSize l_size = (CeedSize)num_elem * Q * num_active_in * num_active_out;
465     CeedCallBackend(CeedVectorCreate(ceed_parent, l_size, assembled));
466   }
467   // Clear output vector
468   CeedCallBackend(CeedVectorSetValue(*assembled, 0.0));
469   CeedCallBackend(CeedVectorGetArray(*assembled, CEED_MEM_HOST, &a));
470 
471   // Loop through elements
472   for (CeedInt e = 0; e < num_elem; e++) {
473     // Input basis apply
474     CeedCallBackend(CeedOperatorInputBasis_Ref(e, Q, qf_input_fields, op_input_fields, num_input_fields, true, e_data_full, impl));
475 
476     // Assemble QFunction
477     for (CeedInt in = 0; in < num_active_in; in++) {
478       // Set Inputs
479       CeedCallBackend(CeedVectorSetValue(active_in[in], 1.0));
480       if (num_active_in > 1) {
481         CeedCallBackend(CeedVectorSetValue(active_in[(in + num_active_in - 1) % num_active_in], 0.0));
482       }
483       // Set Outputs
484       for (CeedInt out = 0; out < num_output_fields; out++) {
485         // Get output vector
486         CeedCallBackend(CeedOperatorFieldGetVector(op_output_fields[out], &vec));
487         // Check if active output
488         if (vec == CEED_VECTOR_ACTIVE) {
489           CeedCallBackend(CeedVectorSetArray(impl->q_vecs_out[out], CEED_MEM_HOST, CEED_USE_POINTER, a));
490           CeedCallBackend(CeedQFunctionFieldGetSize(qf_output_fields[out], &size));
491           a += size * Q;  // Advance the pointer by the size of the output
492         }
493       }
494       // Apply QFunction
495       CeedCallBackend(CeedQFunctionApply(qf, Q, impl->q_vecs_in, impl->q_vecs_out));
496     }
497   }
498 
499   // Un-set output Qvecs to prevent accidental overwrite of Assembled
500   for (CeedInt out = 0; out < num_output_fields; out++) {
501     // Get output vector
502     CeedCallBackend(CeedOperatorFieldGetVector(op_output_fields[out], &vec));
503     // Check if active output
504     if (vec == CEED_VECTOR_ACTIVE && num_elem > 0) {
505       CeedCallBackend(CeedVectorTakeArray(impl->q_vecs_out[out], CEED_MEM_HOST, NULL));
506     }
507   }
508 
509   // Restore input arrays
510   CeedCallBackend(CeedOperatorRestoreInputs_Ref(num_input_fields, qf_input_fields, op_input_fields, true, e_data_full, impl));
511 
512   // Restore output
513   CeedCallBackend(CeedVectorRestoreArray(*assembled, &a));
514 
515   return CEED_ERROR_SUCCESS;
516 }
517 
518 //------------------------------------------------------------------------------
519 // Assemble Linear QFunction
520 //------------------------------------------------------------------------------
521 static int CeedOperatorLinearAssembleQFunction_Ref(CeedOperator op, CeedVector *assembled, CeedElemRestriction *rstr, CeedRequest *request) {
522   return CeedOperatorLinearAssembleQFunctionCore_Ref(op, true, assembled, rstr, request);
523 }
524 
525 //------------------------------------------------------------------------------
526 // Update Assembled Linear QFunction
527 //------------------------------------------------------------------------------
528 static int CeedOperatorLinearAssembleQFunctionUpdate_Ref(CeedOperator op, CeedVector assembled, CeedElemRestriction rstr, CeedRequest *request) {
529   return CeedOperatorLinearAssembleQFunctionCore_Ref(op, false, &assembled, &rstr, request);
530 }
531 
532 //------------------------------------------------------------------------------
533 // Operator Destroy
534 //------------------------------------------------------------------------------
535 static int CeedOperatorDestroy_Ref(CeedOperator op) {
536   CeedOperator_Ref *impl;
537   CeedCallBackend(CeedOperatorGetData(op, &impl));
538 
539   for (CeedInt i = 0; i < impl->num_inputs + impl->num_outputs; i++) {
540     CeedCallBackend(CeedVectorDestroy(&impl->e_vecs_full[i]));
541   }
542   CeedCallBackend(CeedFree(&impl->e_vecs_full));
543   CeedCallBackend(CeedFree(&impl->input_states));
544 
545   for (CeedInt i = 0; i < impl->num_inputs; i++) {
546     CeedCallBackend(CeedVectorDestroy(&impl->e_vecs_in[i]));
547     CeedCallBackend(CeedVectorDestroy(&impl->q_vecs_in[i]));
548   }
549   CeedCallBackend(CeedFree(&impl->e_vecs_in));
550   CeedCallBackend(CeedFree(&impl->q_vecs_in));
551 
552   for (CeedInt i = 0; i < impl->num_outputs; i++) {
553     CeedCallBackend(CeedVectorDestroy(&impl->e_vecs_out[i]));
554     CeedCallBackend(CeedVectorDestroy(&impl->q_vecs_out[i]));
555   }
556   CeedCallBackend(CeedFree(&impl->e_vecs_out));
557   CeedCallBackend(CeedFree(&impl->q_vecs_out));
558 
559   // QFunction assembly
560   for (CeedInt i = 0; i < impl->num_active_in; i++) {
561     CeedCallBackend(CeedVectorDestroy(&impl->qf_active_in[i]));
562   }
563   CeedCallBackend(CeedFree(&impl->qf_active_in));
564 
565   CeedCallBackend(CeedFree(&impl));
566   return CEED_ERROR_SUCCESS;
567 }
568 
569 //------------------------------------------------------------------------------
570 // Operator Create
571 //------------------------------------------------------------------------------
572 int CeedOperatorCreate_Ref(CeedOperator op) {
573   Ceed ceed;
574   CeedCallBackend(CeedOperatorGetCeed(op, &ceed));
575   CeedOperator_Ref *impl;
576 
577   CeedCallBackend(CeedCalloc(1, &impl));
578   CeedCallBackend(CeedOperatorSetData(op, impl));
579 
580   CeedCallBackend(CeedSetBackendFunction(ceed, "Operator", op, "LinearAssembleQFunction", CeedOperatorLinearAssembleQFunction_Ref));
581   CeedCallBackend(CeedSetBackendFunction(ceed, "Operator", op, "LinearAssembleQFunctionUpdate", CeedOperatorLinearAssembleQFunctionUpdate_Ref));
582   CeedCallBackend(CeedSetBackendFunction(ceed, "Operator", op, "ApplyAdd", CeedOperatorApplyAdd_Ref));
583   CeedCallBackend(CeedSetBackendFunction(ceed, "Operator", op, "Destroy", CeedOperatorDestroy_Ref));
584   return CEED_ERROR_SUCCESS;
585 }
586