xref: /libCEED/backends/cuda-gen/ceed-cuda-gen-operator-build.cpp (revision 70dc8078dbe287928145230e5a499c81da54eabb)
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 #define CEED_DEBUG_COLOR 12
9 
10 #include <ceed.h>
11 #include <ceed/backend.h>
12 #include <ceed/jit-tools.h>
13 #include <cuda_runtime.h>
14 
15 #include <iostream>
16 #include <sstream>
17 #include <string>
18 
19 #include "../cuda-ref/ceed-cuda-ref.h"
20 #include "../cuda-shared/ceed-cuda-shared.h"
21 #include "../cuda/ceed-cuda-common.h"
22 #include "../cuda/ceed-cuda-compile.h"
23 #include "ceed-cuda-gen.h"
24 
25 //------------------------------------------------------------------------------
26 // Determine type of operator
27 //------------------------------------------------------------------------------
28 static int CeedOperatorBuildKernelData_Cuda_gen(Ceed ceed, CeedInt num_input_fields, CeedOperatorField *op_input_fields,
29                                                 CeedQFunctionField *qf_input_fields, CeedInt num_output_fields, CeedOperatorField *op_output_fields,
30                                                 CeedQFunctionField *qf_output_fields, CeedInt *max_P_1d, CeedInt *Q_1d, CeedInt *dim, bool *is_tensor,
31                                                 bool *use_3d_slices) {
32   // Find dim, P_1d, Q_1d
33   *max_P_1d  = 0;
34   *Q_1d      = 0;
35   *dim       = 0;
36   *is_tensor = true;
37   for (CeedInt i = 0; i < num_input_fields; i++) {
38     CeedBasis basis;
39 
40     CeedCallBackend(CeedOperatorFieldGetBasis(op_input_fields[i], &basis));
41     if (basis != CEED_BASIS_NONE) {
42       bool    is_field_tensor;
43       CeedInt field_P_1d = 0, field_Q_1d = 0, field_dim = 0;
44 
45       // Collect dim, P_1d, and Q_1d
46       CeedCallBackend(CeedBasisIsTensor(basis, &is_field_tensor));
47       CeedCheck(is_field_tensor, ceed, CEED_ERROR_BACKEND, "Backend does not implement operators with non-tensor basis");
48       *is_tensor = *is_tensor && is_field_tensor;
49       CeedCallBackend(CeedBasisGetNumNodes1D(basis, &field_P_1d));
50       *max_P_1d = CeedIntMax(*max_P_1d, field_P_1d);
51       CeedCallBackend(CeedBasisGetDimension(basis, &field_dim));
52       CeedCheck(*dim == 0 || field_dim == *dim, ceed, CEED_ERROR_BACKEND, "Quadrature spaces must be compatible");
53       *dim = field_dim;
54       CeedCallBackend(CeedBasisGetNumQuadraturePoints1D(basis, &field_Q_1d));
55       CeedCheck(*Q_1d == 0 || field_Q_1d == *Q_1d, ceed, CEED_ERROR_BACKEND, "Quadrature spaces must be compatible");
56       *Q_1d = field_Q_1d;
57     }
58   }
59   for (CeedInt i = 0; i < num_output_fields; i++) {
60     CeedBasis basis;
61 
62     CeedCallBackend(CeedOperatorFieldGetBasis(op_output_fields[i], &basis));
63     if (basis != CEED_BASIS_NONE) {
64       bool    is_field_tensor;
65       CeedInt field_P_1d = 0, field_Q_1d = 0, field_dim = 0;
66 
67       // Collect dim, P_1d, and Q_1d
68       CeedCallBackend(CeedBasisIsTensor(basis, &is_field_tensor));
69       CeedCheck(is_field_tensor, ceed, CEED_ERROR_BACKEND, "Backend does not implement operators with non-tensor basis");
70       *is_tensor = *is_tensor && is_field_tensor;
71       CeedCallBackend(CeedBasisGetNumNodes1D(basis, &field_P_1d));
72       *max_P_1d = CeedIntMax(*max_P_1d, field_P_1d);
73       CeedCallBackend(CeedBasisGetDimension(basis, &field_dim));
74       CeedCheck(*dim == 0 || field_dim == *dim, ceed, CEED_ERROR_BACKEND, "Quadrature spaces must be compatible");
75       *dim = field_dim;
76       CeedCallBackend(CeedBasisGetNumQuadraturePoints1D(basis, &field_Q_1d));
77       CeedCheck(*Q_1d == 0 || field_Q_1d == *Q_1d, ceed, CEED_ERROR_BACKEND, "Quadrature spaces must be compatible");
78       *Q_1d = field_Q_1d;
79     }
80   }
81 
82   // Only use 3D collocated gradient parallelization strategy when gradient is computed
83   *use_3d_slices = false;
84   if (*dim == 3) {
85     bool was_grad_found = false;
86 
87     for (CeedInt i = 0; i < num_input_fields; i++) {
88       CeedEvalMode eval_mode;
89 
90       CeedCallBackend(CeedQFunctionFieldGetEvalMode(qf_input_fields[i], &eval_mode));
91       if (eval_mode == CEED_EVAL_GRAD) {
92         CeedBasis_Cuda_shared *basis_data;
93         CeedBasis              basis;
94 
95         CeedCallBackend(CeedOperatorFieldGetBasis(op_input_fields[i], &basis));
96         CeedCallBackend(CeedBasisGetData(basis, &basis_data));
97         *use_3d_slices = basis_data->d_collo_grad_1d && (was_grad_found ? *use_3d_slices : true);
98         was_grad_found = true;
99       }
100     }
101     for (CeedInt i = 0; i < num_output_fields; i++) {
102       CeedEvalMode eval_mode;
103 
104       CeedCallBackend(CeedQFunctionFieldGetEvalMode(qf_output_fields[i], &eval_mode));
105       if (eval_mode == CEED_EVAL_GRAD) {
106         CeedBasis_Cuda_shared *basis_data;
107         CeedBasis              basis;
108 
109         CeedCallBackend(CeedOperatorFieldGetBasis(op_output_fields[i], &basis));
110         CeedCallBackend(CeedBasisGetData(basis, &basis_data));
111         *use_3d_slices = basis_data->d_collo_grad_1d && (was_grad_found ? *use_3d_slices : true);
112         was_grad_found = true;
113       }
114     }
115   }
116   return CEED_ERROR_SUCCESS;
117 }
118 
119 //------------------------------------------------------------------------------
120 // Setup fields
121 //------------------------------------------------------------------------------
122 static int CeedOperatorBuildKernelFieldData_Cuda_gen(std::ostringstream &code, CeedOperator_Cuda_gen *data, CeedInt i, CeedOperatorField op_field,
123                                                      CeedQFunctionField qf_field, CeedInt Q_1d, bool is_input, bool use_3d_slices) {
124   std::string            var_suffix = (is_input ? "_in_" : "_out_") + std::to_string(i);
125   std::string            P_name = "P_1d" + var_suffix, Q_name = "Q_1d";
126   std::string            option_name = (is_input ? "inputs" : "outputs");
127   CeedEvalMode           eval_mode   = CEED_EVAL_NONE;
128   CeedInt                elem_size = 0, num_comp = 0, P_1d = 0;
129   CeedElemRestriction    elem_rstr;
130   CeedBasis_Cuda_shared *basis_data;
131   CeedBasis              basis;
132 
133   code << "  // -- " << (is_input ? "Input" : "Output") << " field " << i << "\n";
134 
135   // Get field data
136   CeedCallBackend(CeedOperatorFieldGetElemRestriction(op_field, &elem_rstr));
137   if (elem_rstr != CEED_ELEMRESTRICTION_NONE) {
138     CeedCallBackend(CeedElemRestrictionGetElementSize(elem_rstr, &elem_size));
139     CeedCallBackend(CeedElemRestrictionGetNumComponents(elem_rstr, &num_comp));
140   }
141   CeedCallBackend(CeedOperatorFieldGetBasis(op_field, &basis));
142   if (basis != CEED_BASIS_NONE) {
143     CeedCallBackend(CeedBasisGetData(basis, &basis_data));
144     CeedCallBackend(CeedBasisGetNumNodes1D(basis, &P_1d));
145   }
146   CeedCallBackend(CeedQFunctionFieldGetEvalMode(qf_field, &eval_mode));
147 
148   // Set field constants
149   if (eval_mode != CEED_EVAL_WEIGHT) {
150     code << "  const CeedInt " << P_name << " = " << (basis == CEED_BASIS_NONE ? Q_1d : P_1d) << ";\n";
151     code << "  const CeedInt num_comp" << var_suffix << " = " << num_comp << ";\n";
152   }
153 
154   // Load basis data
155   code << "  // EvalMode: " << CeedEvalModes[eval_mode] << "\n";
156   switch (eval_mode) {
157     case CEED_EVAL_NONE:
158       break;
159     case CEED_EVAL_INTERP:
160       if (is_input) data->B.inputs[i] = basis_data->d_interp_1d;
161       else data->B.outputs[i] = basis_data->d_interp_1d;
162       code << "  __shared__ CeedScalar s_B" << var_suffix << "[" << P_1d * Q_1d << "];\n";
163       code << "  loadMatrix<" << P_name << ", " << Q_name << ">(data, B." << option_name << "[" << i << "], s_B" << var_suffix << ");\n";
164       break;
165     case CEED_EVAL_GRAD:
166       if (is_input) data->B.inputs[i] = basis_data->d_interp_1d;
167       else data->B.outputs[i] = basis_data->d_interp_1d;
168       code << "  __shared__ CeedScalar s_B" << var_suffix << "[" << P_1d * Q_1d << "];\n";
169       code << "  loadMatrix<" << P_name << ", " << Q_name << ">(data, B." << option_name << "[" << i << "], s_B" << var_suffix << ");\n";
170       if (use_3d_slices) {
171         if (is_input) data->G.inputs[i] = basis_data->d_collo_grad_1d;
172         else data->G.outputs[i] = basis_data->d_collo_grad_1d;
173         code << "  __shared__ CeedScalar s_G" << var_suffix << "[" << Q_1d * Q_1d << "];\n";
174         code << "  loadMatrix<" << Q_name << ", " << Q_name << ">(data, G." << option_name << "[" << i << "], s_G" << var_suffix << ");\n";
175       } else {
176         bool has_collo_grad = basis_data->d_collo_grad_1d;
177 
178         if (is_input) data->G.inputs[i] = has_collo_grad ? basis_data->d_collo_grad_1d : basis_data->d_grad_1d;
179         else data->G.outputs[i] = has_collo_grad ? basis_data->d_collo_grad_1d : basis_data->d_grad_1d;
180         if (has_collo_grad) {
181           code << "  __shared__ CeedScalar s_G" << var_suffix << "[" << Q_1d * Q_1d << "];\n";
182           code << "  loadMatrix<" << Q_name << ", " << Q_name << ">(data, G." << option_name << "[" << i << "], s_G" << var_suffix << ");\n";
183         } else {
184           code << "  __shared__ CeedScalar s_G" << var_suffix << "[" << Q_1d * P_1d << "];\n";
185           code << "  loadMatrix<" << P_name << ", " << Q_name << ">(data, G." << option_name << "[" << i << "], s_G" << var_suffix << ");\n";
186         }
187       }
188       break;
189     case CEED_EVAL_WEIGHT:
190       break;  // No action
191       // LCOV_EXCL_START
192     case CEED_EVAL_DIV:
193       break;  // TODO: Not implemented
194     case CEED_EVAL_CURL:
195       break;  // TODO: Not implemented
196               // LCOV_EXCL_STOP
197   }
198   return CEED_ERROR_SUCCESS;
199 }
200 
201 //------------------------------------------------------------------------------
202 // Restriction
203 //------------------------------------------------------------------------------
204 static int CeedOperatorBuildKernelRestriction_Cuda_gen(std::ostringstream &code, CeedOperator_Cuda_gen *data, CeedInt i, CeedInt dim,
205                                                        CeedOperatorField op_field, CeedQFunctionField qf_field, CeedInt Q_1d, bool is_input,
206                                                        bool use_3d_slices) {
207   std::string               var_suffix = (is_input ? "_in_" : "_out_") + std::to_string(i);
208   std::string               P_name     = "P_1d" + var_suffix;
209   CeedEvalMode              eval_mode  = CEED_EVAL_NONE;
210   CeedInt                   elem_size = 0, num_comp = 0, P_1d = 0;
211   CeedSize                  l_size;
212   CeedElemRestriction_Cuda *rstr_data;
213   CeedElemRestriction       elem_rstr;
214   CeedBasis                 basis;
215 
216   // Get field data
217   CeedCallBackend(CeedOperatorFieldGetElemRestriction(op_field, &elem_rstr));
218   if (elem_rstr != CEED_ELEMRESTRICTION_NONE) {
219     CeedCallBackend(CeedElemRestrictionGetElementSize(elem_rstr, &elem_size));
220     CeedCallBackend(CeedElemRestrictionGetNumComponents(elem_rstr, &num_comp));
221     CeedCallBackend(CeedElemRestrictionGetData(elem_rstr, &rstr_data));
222   }
223   CeedCallBackend(CeedOperatorFieldGetBasis(op_field, &basis));
224   if (basis != CEED_BASIS_NONE) {
225     CeedCallBackend(CeedBasisGetNumNodes1D(basis, &P_1d));
226   }
227   CeedCallBackend(CeedQFunctionFieldGetEvalMode(qf_field, &eval_mode));
228 
229   // Restriction
230   if (is_input) {
231     // Input
232     if (eval_mode != CEED_EVAL_WEIGHT && !((eval_mode == CEED_EVAL_NONE) && use_3d_slices)) {
233       bool is_strided;
234 
235       code << "    CeedScalar r_e" << var_suffix << "[num_comp" << var_suffix << "*" << P_name << "];\n";
236       CeedCallBackend(CeedElemRestrictionIsStrided(elem_rstr, &is_strided));
237       if (!is_strided) {
238         CeedInt comp_stride;
239 
240         CeedCallBackend(CeedElemRestrictionGetLVectorSize(elem_rstr, &l_size));
241         code << "    const CeedInt l_size" << var_suffix << " = " << l_size << ";\n";
242         CeedCallBackend(CeedElemRestrictionGetCompStride(elem_rstr, &comp_stride));
243         code << "    // CompStride: " << comp_stride << "\n";
244         data->indices.inputs[i] = (CeedInt *)rstr_data->d_offsets;
245         code << "    readDofsOffset" << dim << "d<num_comp" << var_suffix << ", " << comp_stride << ", " << P_name << ">(data, l_size" << var_suffix
246              << ", elem, indices.inputs[" << i << "], d" << var_suffix << ", r_e" << var_suffix << ");\n";
247       } else {
248         bool    has_backend_strides;
249         CeedInt num_elem;
250 
251         CeedCallBackend(CeedElemRestrictionHasBackendStrides(elem_rstr, &has_backend_strides));
252         CeedCallBackend(CeedElemRestrictionGetNumElements(elem_rstr, &num_elem));
253         CeedInt strides[3] = {1, elem_size * num_elem, elem_size};
254 
255         if (!has_backend_strides) {
256           CeedCallBackend(CeedElemRestrictionGetStrides(elem_rstr, strides));
257         }
258         code << "    // Strides: {" << strides[0] << ", " << strides[1] << ", " << strides[2] << "}\n";
259         code << "    readDofsStrided" << dim << "d<num_comp" << var_suffix << ", " << P_name << "," << strides[0] << "," << strides[1] << ","
260              << strides[2] << ">(data, elem, d" << var_suffix << ", r_e" << var_suffix << ");\n";
261       }
262     }
263   } else {
264     // Output
265     bool is_strided;
266 
267     CeedCallBackend(CeedElemRestrictionIsStrided(elem_rstr, &is_strided));
268     if (!is_strided) {
269       CeedInt comp_stride;
270 
271       CeedCallBackend(CeedElemRestrictionGetLVectorSize(elem_rstr, &l_size));
272       code << "    const CeedInt l_size" << var_suffix << " = " << l_size << ";\n";
273       CeedCallBackend(CeedElemRestrictionGetCompStride(elem_rstr, &comp_stride));
274       code << "    // CompStride: " << comp_stride << "\n";
275       data->indices.outputs[i] = (CeedInt *)rstr_data->d_offsets;
276       code << "    writeDofsOffset" << dim << "d<num_comp" << var_suffix << ", " << comp_stride << ", " << P_name << ">(data, l_size" << var_suffix
277            << ", elem, indices.outputs[" << i << "], r_e" << var_suffix << ", d" << var_suffix << ");\n";
278     } else {
279       bool    has_backend_strides;
280       CeedInt num_elem;
281 
282       CeedCallBackend(CeedElemRestrictionHasBackendStrides(elem_rstr, &has_backend_strides));
283       CeedCallBackend(CeedElemRestrictionGetNumElements(elem_rstr, &num_elem));
284       CeedInt strides[3] = {1, elem_size * num_elem, elem_size};
285 
286       if (!has_backend_strides) {
287         CeedCallBackend(CeedElemRestrictionGetStrides(elem_rstr, strides));
288       }
289       code << "    // Strides: {" << strides[0] << ", " << strides[1] << ", " << strides[2] << "}\n";
290       code << "    writeDofsStrided" << dim << "d<num_comp" << var_suffix << ", " << P_name << "," << strides[0] << "," << strides[1] << ","
291            << strides[2] << ">(data, elem, r_e" << var_suffix << ", d" << var_suffix << ");\n";
292     }
293   }
294   return CEED_ERROR_SUCCESS;
295 }
296 
297 //------------------------------------------------------------------------------
298 // Basis
299 //------------------------------------------------------------------------------
300 static int CeedOperatorBuildKernelBasis_Cuda_gen(std::ostringstream &code, CeedOperator_Cuda_gen *data, CeedInt i, CeedInt dim,
301                                                  CeedOperatorField op_field, CeedQFunctionField qf_field, CeedInt Q_1d, bool is_input,
302                                                  bool use_3d_slices) {
303   std::string         var_suffix = (is_input ? "_in_" : "_out_") + std::to_string(i);
304   std::string         P_name = "P_1d" + var_suffix, Q_name = "Q_1d";
305   CeedEvalMode        eval_mode = CEED_EVAL_NONE;
306   CeedInt             elem_size = 0, num_comp = 0, P_1d = 0;
307   CeedElemRestriction elem_rstr;
308   CeedBasis           basis;
309 
310   // Get field data
311   CeedCallBackend(CeedOperatorFieldGetElemRestriction(op_field, &elem_rstr));
312   if (elem_rstr != CEED_ELEMRESTRICTION_NONE) {
313     CeedCallBackend(CeedElemRestrictionGetElementSize(elem_rstr, &elem_size));
314     CeedCallBackend(CeedElemRestrictionGetNumComponents(elem_rstr, &num_comp));
315   }
316   CeedCallBackend(CeedOperatorFieldGetBasis(op_field, &basis));
317   if (basis != CEED_BASIS_NONE) {
318     CeedCallBackend(CeedBasisGetNumNodes1D(basis, &P_1d));
319   }
320   CeedCallBackend(CeedQFunctionFieldGetEvalMode(qf_field, &eval_mode));
321 
322   // Basis
323   code << "    // EvalMode: " << CeedEvalModes[eval_mode] << "\n";
324   if (is_input) {
325     switch (eval_mode) {
326       case CEED_EVAL_NONE:
327         if (!use_3d_slices) {
328           code << "    CeedScalar *r_q" << var_suffix << " = r_e" << var_suffix << ";\n";
329         }
330         break;
331       case CEED_EVAL_INTERP:
332         code << "    CeedScalar r_q" << var_suffix << "[num_comp" << var_suffix << "*" << Q_name << "];\n";
333         code << "    Interp" << (dim > 1 ? "Tensor" : "") << dim << "d<num_comp" << var_suffix << ", P_1d" << var_suffix << ", " << Q_name
334              << ">(data, r_e" << var_suffix << ", s_B" << var_suffix << ", r_q" << var_suffix << ");\n";
335         break;
336       case CEED_EVAL_GRAD:
337         if (use_3d_slices) {
338           code << "    CeedScalar r_q" << var_suffix << "[num_comp" << var_suffix << "*" << Q_name << "];\n";
339           code << "    Interp" << (dim > 1 ? "Tensor" : "") << dim << "d<num_comp" << var_suffix << ", P_1d" << var_suffix << ", " << Q_name
340                << ">(data, r_e" << var_suffix << ", s_B" << var_suffix << ", r_q" << var_suffix << ");\n";
341         } else {
342           code << "    CeedScalar r_q" << var_suffix << "[num_comp" << var_suffix << "*dim*" << Q_name << "];\n";
343           code << "    Grad" << (dim > 1 ? "Tensor" : "") << (dim == 3 && Q_1d >= P_1d ? "Collocated" : "") << dim << "d<num_comp" << var_suffix
344                << ", P_1d" << var_suffix << ", " << Q_name << ">(data, r_e" << var_suffix << ", s_B" << var_suffix << ", s_G" << var_suffix << ", r_q"
345                << var_suffix << ");\n";
346         }
347         break;
348       case CEED_EVAL_WEIGHT: {
349         CeedBasis_Cuda_shared *basis_data;
350 
351         code << "    CeedScalar r_q" << var_suffix << "[" << Q_name << "];\n";
352         CeedCallBackend(CeedBasisGetData(basis, &basis_data));
353         data->W = basis_data->d_q_weight_1d;
354         code << "    Weight" << (dim > 1 ? "Tensor" : "") << dim << "d<" << Q_name << ">(data, W, r_q" << var_suffix << ");\n";
355         break;
356       }
357       // LCOV_EXCL_START
358       case CEED_EVAL_DIV:
359         break;  // TODO: Not implemented
360       case CEED_EVAL_CURL:
361         break;  // TODO: Not implemented
362                 // LCOV_EXCL_STOP
363     }
364   } else {
365     switch (eval_mode) {
366       case CEED_EVAL_NONE:
367         code << "    CeedScalar *r_e" << var_suffix << " = r_q" << var_suffix << ";\n";
368         break;  // No action
369       case CEED_EVAL_INTERP:
370         code << "    CeedScalar r_e" << var_suffix << "[num_comp" << var_suffix << "*" << P_name << "];\n";
371         code << "    InterpTranspose" << (dim > 1 ? "Tensor" : "") << dim << "d<num_comp" << var_suffix << ", " << P_name << ", " << Q_name
372              << ">(data, r_q" << var_suffix << ", s_B" << var_suffix << ", r_e" << var_suffix << ");\n";
373         break;
374       case CEED_EVAL_GRAD:
375         code << "    CeedScalar r_e" << var_suffix << "[num_comp" << var_suffix << "*" << P_name << "];\n";
376         if (use_3d_slices) {
377           code << "    InterpTranspose" << (dim > 1 ? "Tensor" : "") << dim << "d<num_comp" << var_suffix << ", " << P_name << ", " << Q_name
378                << ">(data, r_q" << var_suffix << ", s_B" << var_suffix << ", r_e" << var_suffix << ");\n";
379         } else {
380           code << "    GradTranspose" << (dim > 1 ? "Tensor" : "") << (dim == 3 && Q_1d >= P_1d ? "Collocated" : "") << dim << "d<num_comp"
381                << var_suffix << ", " << P_name << "," << Q_name << ">(data, r_q" << var_suffix << ", s_B" << var_suffix << ", s_G" << var_suffix
382                << ", r_e" << var_suffix << ");\n";
383         }
384         break;
385       // LCOV_EXCL_START
386       case CEED_EVAL_WEIGHT:
387         break;  // Should not occur
388       case CEED_EVAL_DIV:
389         break;  // TODO: Not implemented
390       case CEED_EVAL_CURL:
391         break;  // TODO: Not implemented
392                 // LCOV_EXCL_STOP
393     }
394   }
395   return CEED_ERROR_SUCCESS;
396 }
397 
398 //------------------------------------------------------------------------------
399 // QFunction
400 //------------------------------------------------------------------------------
401 static int CeedOperatorBuildKernelQFunction_Cuda_gen(std::ostringstream &code, CeedOperator_Cuda_gen *data, CeedInt dim, CeedInt num_input_fields,
402                                                      CeedOperatorField *op_input_fields, CeedQFunctionField *qf_input_fields,
403                                                      CeedInt num_output_fields, CeedOperatorField *op_output_fields,
404                                                      CeedQFunctionField *qf_output_fields, std::string qfunction_name, CeedInt Q_1d,
405                                                      bool use_3d_slices) {
406   std::string         Q_name    = "Q_1d";
407   CeedEvalMode        eval_mode = CEED_EVAL_NONE;
408   CeedElemRestriction elem_rstr;
409 
410   // Setup output arays
411   code << "\n    // -- Output field setup\n";
412   for (CeedInt i = 0; i < num_output_fields; i++) {
413     std::string var_suffix = "_out_" + std::to_string(i);
414 
415     code << "    // ---- Output field " << i << "\n";
416     CeedCallBackend(CeedQFunctionFieldGetEvalMode(qf_output_fields[i], &eval_mode));
417     if (eval_mode == CEED_EVAL_NONE || eval_mode == CEED_EVAL_INTERP) {
418       code << "    CeedScalar r_q" << var_suffix << "[num_comp" << var_suffix << "*" << Q_name << "];\n";
419     }
420     if (eval_mode == CEED_EVAL_GRAD) {
421       if (use_3d_slices) {
422         // Accumulator for gradient slices
423         code << "    CeedScalar r_q" << var_suffix << "[num_comp" << var_suffix << "*" << Q_name << "];\n";
424         code << "    for (CeedInt i = 0; i < num_comp" << var_suffix << "*" << Q_name << "; i++) {\n";
425         code << "      r_q" << var_suffix << "[i] = 0.0;\n";
426         code << "    }\n";
427       } else {
428         code << "    CeedScalar r_q" << var_suffix << "[num_comp" << var_suffix << "*dim*" << Q_name << "];\n";
429       }
430     }
431   }
432 
433   // We treat quadrature points per slice in 3d to save registers
434   if (use_3d_slices) {
435     code << "\n    // Note: Using planes of 3D elements\n";
436     code << "#pragma unroll\n";
437     code << "    for (CeedInt q = 0; q < " << Q_name << "; q++) {\n";
438     code << "      // -- Input fields\n";
439     for (CeedInt i = 0; i < num_input_fields; i++) {
440       std::string var_suffix = "_in_" + std::to_string(i);
441 
442       code << "      // ---- Input field " << i << "\n";
443       CeedCallBackend(CeedQFunctionFieldGetEvalMode(qf_input_fields[i], &eval_mode));
444       // Basis action
445       code << "      // EvalMode: " << CeedEvalModes[eval_mode] << "\n";
446       switch (eval_mode) {
447         case CEED_EVAL_NONE:
448           bool is_strided;
449 
450           code << "      CeedScalar r_s" << var_suffix << "[num_comp" << var_suffix << "];\n";
451 
452           CeedCallBackend(CeedOperatorFieldGetElemRestriction(op_input_fields[i], &elem_rstr));
453           CeedCallBackend(CeedElemRestrictionIsStrided(elem_rstr, &is_strided));
454           if (is_strided) {
455             bool    has_backend_strides;
456             CeedInt num_elem, elem_size;
457 
458             CeedCallBackend(CeedElemRestrictionGetElementSize(elem_rstr, &elem_size));
459             CeedCallBackend(CeedElemRestrictionHasBackendStrides(elem_rstr, &has_backend_strides));
460             CeedCallBackend(CeedElemRestrictionGetNumElements(elem_rstr, &num_elem));
461             CeedInt strides[3] = {1, elem_size * num_elem, elem_size};
462 
463             if (!has_backend_strides) {
464               CeedCallBackend(CeedElemRestrictionGetStrides(elem_rstr, strides));
465             }
466             code << "      // Strides: {" << strides[0] << ", " << strides[1] << ", " << strides[2] << "}\n";
467             code << "      readSliceQuadsStrided3d<num_comp" << var_suffix << ", " << Q_name << "," << strides[0] << "," << strides[1] << ","
468                  << strides[2] << ">(data, elem, q, d" << var_suffix << ", r_s" << var_suffix << ");\n";
469           } else {
470             CeedSize                  l_size = 0;
471             CeedInt                   comp_stride;
472             CeedElemRestriction_Cuda *rstr_data;
473 
474             CeedCallBackend(CeedElemRestrictionGetLVectorSize(elem_rstr, &l_size));
475             code << "      const CeedInt l_size" << var_suffix << " = " << l_size << ";\n";
476             CeedCallBackend(CeedElemRestrictionGetCompStride(elem_rstr, &comp_stride));
477             code << "      // CompStride: " << comp_stride << "\n";
478             CeedCallBackend(CeedElemRestrictionGetData(elem_rstr, &rstr_data));
479             data->indices.inputs[i] = (CeedInt *)rstr_data->d_offsets;
480             code << "      readSliceQuadsOffset3d<num_comp" << var_suffix << ", " << comp_stride << ", " << Q_name << ">(data, l_size" << var_suffix
481                  << ", elem, q, indices.inputs[" << i << "], d" << var_suffix << ", r_s" << var_suffix << ");\n";
482           }
483           break;
484         case CEED_EVAL_INTERP:
485           code << "      CeedScalar r_s" << var_suffix << "[num_comp" << var_suffix << "];\n";
486           code << "      for (CeedInt j = 0; j < num_comp" << var_suffix << "; j++) {\n";
487           code << "        r_s" << var_suffix << "[j] = r_q" << var_suffix << "[q + j*" << Q_name << "];\n";
488           code << "      }\n";
489           break;
490         case CEED_EVAL_GRAD:
491           code << "      CeedScalar r_s" << var_suffix << "[num_comp" << var_suffix << "*dim];\n";
492           code << "      gradCollo3d<num_comp" << var_suffix << ", " << Q_name << ">(data, q, r_q" << var_suffix << ", s_G" << var_suffix << ", r_s"
493                << var_suffix << ");\n";
494           break;
495         case CEED_EVAL_WEIGHT:
496           code << "      CeedScalar r_s" << var_suffix << "[1];\n";
497           code << "      r_s" << var_suffix << "[0] = r_q" << var_suffix << "[q];\n";
498           break;  // No action
499                   // LCOV_EXCL_START
500         case CEED_EVAL_DIV:
501           break;  // TODO: Not implemented
502         case CEED_EVAL_CURL:
503           break;  // TODO: Not implemented
504                   // LCOV_EXCL_STOP
505       }
506     }
507     code << "\n      // -- Output fields\n";
508     for (CeedInt i = 0; i < num_output_fields; i++) {
509       std::string var_suffix = "_out_" + std::to_string(i);
510 
511       code << "      // ---- Output field " << i << "\n";
512       CeedCallBackend(CeedQFunctionFieldGetEvalMode(qf_output_fields[i], &eval_mode));
513       // Basis action
514       switch (eval_mode) {
515         case CEED_EVAL_NONE:
516           code << "      CeedScalar r_s" << var_suffix << "[num_comp" << var_suffix << "];\n";
517           break;  // No action
518         case CEED_EVAL_INTERP:
519           code << "      CeedScalar r_s" << var_suffix << "[num_comp" << var_suffix << "];\n";
520           break;
521         case CEED_EVAL_GRAD:
522           code << "      CeedScalar r_s" << var_suffix << "[num_comp" << var_suffix << "*dim];\n";
523           break;
524           // LCOV_EXCL_START
525         case CEED_EVAL_WEIGHT:
526           break;  // Should not occur
527         case CEED_EVAL_DIV:
528           break;  // TODO: Not implemented
529         case CEED_EVAL_CURL:
530           break;  // TODO: Not implemented
531                   // LCOV_EXCL_STOP
532       }
533     }
534   } else {
535     code << "\n    // Note: Using full elements\n";
536     code << "    {\n";
537     code << "      // -- Input fields\n";
538     for (CeedInt i = 0; i < num_input_fields; i++) {
539       code << "      // ---- Input field " << i << "\n";
540       code << "      CeedScalar *r_s_in_" << i << " = r_q_in_" << i << ";\n";
541     }
542     code << "      // -- Output fields\n";
543     for (CeedInt i = 0; i < num_output_fields; i++) {
544       code << "      // ---- Output field " << i << "\n";
545       code << "      CeedScalar *r_s_out_" << i << " = r_q_out_" << i << ";\n";
546     }
547   }
548 
549   // Input and output buffers
550   code << "\n      // -- QFunction inputs and outputs\n";
551   code << "      // ---- Inputs\n";
552   code << "      CeedScalar *inputs[" << CeedIntMax(num_input_fields, 1) << "];\n";
553   for (CeedInt i = 0; i < num_input_fields; i++) {
554     code << "      // ------ Input field " << i << "\n";
555     code << "      inputs[" << i << "] = r_s_in_" << i << ";\n";
556   }
557   code << "      // ---- Outputs\n";
558   code << "      CeedScalar *outputs[" << CeedIntMax(num_output_fields, 1) << "];\n";
559   for (CeedInt i = 0; i < num_output_fields; i++) {
560     code << "      // ------ Output field " << i << "\n";
561     code << "      outputs[" << i << "] = r_s_out_" << i << ";\n";
562   }
563 
564   // Apply QFunction
565   code << "\n      // -- Apply QFunction\n";
566   code << "      " << qfunction_name << "(ctx, ";
567   if (dim != 3 || use_3d_slices) {
568     code << "1";
569   } else {
570     code << "Q_1d";
571   }
572   code << ", inputs, outputs);\n";
573 
574   // Copy or apply transpose grad, if needed
575   if (use_3d_slices) {
576     code << "      // -- Output fields\n";
577     for (CeedInt i = 0; i < num_output_fields; i++) {
578       std::string var_suffix = "_out_" + std::to_string(i);
579       std::string P_name     = "P_1d" + var_suffix;
580 
581       code << "      // ---- Output field " << i << "\n";
582       CeedCallBackend(CeedQFunctionFieldGetEvalMode(qf_output_fields[i], &eval_mode));
583       // Basis action
584       code << "      // EvalMode: " << CeedEvalModes[eval_mode] << "\n";
585       switch (eval_mode) {
586         case CEED_EVAL_NONE:
587           code << "      for (CeedInt j = 0; j < num_comp" << var_suffix << " ; j++) {\n";
588           code << "        r_q" << var_suffix << "[q + j*" << Q_name << "] = r_s" << var_suffix << "[j];\n";
589           code << "      }\n";
590           break;  // No action
591         case CEED_EVAL_INTERP:
592           code << "      for (CeedInt j = 0; j < num_comp" << var_suffix << " ; j++) {\n";
593           code << "        r_q" << var_suffix << "[q + j*" << Q_name << "] = r_s" << var_suffix << "[j];\n";
594           code << "      }\n";
595           break;
596         case CEED_EVAL_GRAD:
597           code << "      gradColloTranspose3d<num_comp" << var_suffix << ", " << Q_name << ">(data, q, r_s" << var_suffix << ", s_G" << var_suffix
598                << ", r_q" << var_suffix << ");\n";
599           break;
600           // LCOV_EXCL_START
601         case CEED_EVAL_WEIGHT:
602           break;  // Should not occur
603         case CEED_EVAL_DIV:
604           break;  // TODO: Not implemented
605         case CEED_EVAL_CURL:
606           break;  // TODO: Not implemented
607                   // LCOV_EXCL_STOP
608       }
609     }
610   }
611   code << "    }\n";
612   return CEED_ERROR_SUCCESS;
613 }
614 
615 //------------------------------------------------------------------------------
616 // Build single operator kernel
617 //------------------------------------------------------------------------------
618 extern "C" int CeedOperatorBuildKernel_Cuda_gen(CeedOperator op) {
619   bool                    is_tensor = true, use_3d_slices = false;
620   Ceed                    ceed;
621   CeedInt                 Q_1d, num_input_fields, num_output_fields, dim = 1;
622   CeedQFunctionField     *qf_input_fields, *qf_output_fields;
623   CeedQFunction_Cuda_gen *qf_data;
624   CeedQFunction           qf;
625   CeedOperatorField      *op_input_fields, *op_output_fields;
626   CeedOperator_Cuda_gen  *data;
627   std::ostringstream      code;
628 
629   {
630     bool is_setup_done;
631 
632     CeedCallBackend(CeedOperatorIsSetupDone(op, &is_setup_done));
633     if (is_setup_done) return CEED_ERROR_SUCCESS;
634   }
635 
636   CeedCallBackend(CeedOperatorGetCeed(op, &ceed));
637   CeedCallBackend(CeedOperatorGetData(op, &data));
638   CeedCallBackend(CeedOperatorGetQFunction(op, &qf));
639   CeedCallBackend(CeedQFunctionGetData(qf, &qf_data));
640   CeedCallBackend(CeedOperatorGetFields(op, &num_input_fields, &op_input_fields, &num_output_fields, &op_output_fields));
641   CeedCallBackend(CeedQFunctionGetFields(qf, NULL, &qf_input_fields, NULL, &qf_output_fields));
642 
643   // Get operator data
644   CeedCallBackend(CeedOperatorBuildKernelData_Cuda_gen(ceed, num_input_fields, op_input_fields, qf_input_fields, num_output_fields, op_output_fields,
645                                                        qf_output_fields, &data->max_P_1d, &Q_1d, &dim, &is_tensor, &use_3d_slices));
646   if (dim == 0) dim = 1;
647   data->dim = dim;
648   if (Q_1d == 0) {
649     CeedInt Q;
650 
651     CeedCallBackend(CeedOperatorGetNumQuadraturePoints(op, &Q));
652     Q_1d = Q;
653   }
654   data->Q_1d = Q_1d;
655 
656   // Check for restriction only identity operator
657   {
658     bool is_identity_qf;
659 
660     CeedCallBackend(CeedQFunctionIsIdentity(qf, &is_identity_qf));
661     if (is_identity_qf) {
662       CeedEvalMode eval_mode_in, eval_mode_out;
663 
664       CeedCallBackend(CeedQFunctionFieldGetEvalMode(qf_input_fields[0], &eval_mode_in));
665       CeedCallBackend(CeedQFunctionFieldGetEvalMode(qf_output_fields[0], &eval_mode_out));
666       CeedCheck(eval_mode_in != CEED_EVAL_NONE || eval_mode_out != CEED_EVAL_NONE, ceed, CEED_ERROR_BACKEND,
667                 "Backend does not implement restriction only identity operators");
668     }
669   }
670 
671   // Add atomicAdd function for old NVidia architectures
672   {
673     Ceed_Cuda            *ceed_data;
674     struct cudaDeviceProp prop;
675 
676     CeedCallBackend(CeedGetData(ceed, &ceed_data));
677     CeedCallBackend(cudaGetDeviceProperties(&prop, ceed_data->device_id));
678     if ((prop.major < 6) && (CEED_SCALAR_TYPE != CEED_SCALAR_FP32)) {
679       char       *atomic_add_source;
680       const char *atomic_add_path;
681 
682       CeedCallBackend(CeedGetJitAbsolutePath(ceed, "ceed/jit-source/cuda/cuda-atomic-add-fallback.h", &atomic_add_path));
683       CeedDebug256(ceed, CEED_DEBUG_COLOR_SUCCESS, "----- Loading Atomic Add Source -----\n");
684       CeedCallBackend(CeedLoadSourceToBuffer(ceed, atomic_add_path, &atomic_add_source));
685       code << atomic_add_source;
686       CeedCallBackend(CeedFree(&atomic_add_path));
687       CeedCallBackend(CeedFree(&atomic_add_source));
688     }
689   }
690 
691   // Load basis source files
692   // TODO: Add non-tensor, AtPoints
693   {
694     char       *tensor_basis_kernel_source;
695     const char *tensor_basis_kernel_path;
696 
697     CeedCallBackend(CeedGetJitAbsolutePath(ceed, "ceed/jit-source/cuda/cuda-shared-basis-tensor-templates.h", &tensor_basis_kernel_path));
698     CeedDebug256(ceed, CEED_DEBUG_COLOR_SUCCESS, "----- Loading Tensor Basis Kernel Source -----\n");
699     CeedCallBackend(CeedLoadSourceToBuffer(ceed, tensor_basis_kernel_path, &tensor_basis_kernel_source));
700     code << tensor_basis_kernel_source;
701     CeedCallBackend(CeedFree(&tensor_basis_kernel_path));
702     CeedCallBackend(CeedFree(&tensor_basis_kernel_source));
703   }
704   {
705     char       *cuda_gen_template_source;
706     const char *cuda_gen_template_path;
707 
708     CeedCallBackend(CeedGetJitAbsolutePath(ceed, "ceed/jit-source/cuda/cuda-gen-templates.h", &cuda_gen_template_path));
709     CeedDebug256(ceed, CEED_DEBUG_COLOR_SUCCESS, "----- Loading Cuda-Gen Template Source -----\n");
710     CeedCallBackend(CeedLoadSourceToBuffer(ceed, cuda_gen_template_path, &cuda_gen_template_source));
711     code << cuda_gen_template_source;
712     CeedCallBackend(CeedFree(&cuda_gen_template_path));
713     CeedCallBackend(CeedFree(&cuda_gen_template_source));
714   }
715 
716   // Get QFunction name
717   std::string qfunction_name(qf_data->qfunction_name);
718   std::string operator_name;
719 
720   operator_name = "CeedKernelCudaGenOperator_" + qfunction_name;
721 
722   // Define CEED_Q_VLA
723   code << "\n#undef CEED_Q_VLA\n";
724   if (dim != 3 || use_3d_slices) {
725     code << "#define CEED_Q_VLA 1\n\n";
726   } else {
727     code << "#define CEED_Q_VLA " << Q_1d << "\n\n";
728   }
729 
730   // Add user QFunction source
731   {
732     std::string qfunction_source(qf_data->qfunction_source);
733 
734     code << qfunction_source;
735   }
736 
737   // Setup
738   code << "\n// -----------------------------------------------------------------------------\n";
739   code << "// Operator Kernel\n";
740   code << "// \n";
741   code << "// d_[in,out]_i:   CeedVector device array\n";
742   code << "// r_[in,out]_e_i: Element vector register\n";
743   code << "// r_[in,out]_q_i: Quadrature space vector register\n";
744   code << "// r_[in,out]_s_i: Quadrature space slice  vector register\n";
745   code << "// \n";
746   code << "// s_B_[in,out]_i: Interpolation matrix, shared memory\n";
747   code << "// s_G_[in,out]_i: Gradient matrix, shared memory\n";
748   code << "// -----------------------------------------------------------------------------\n";
749   code << "extern \"C\" __global__ void " << operator_name
750        << "(CeedInt num_elem, void* ctx, FieldsInt_Cuda indices, Fields_Cuda fields, Fields_Cuda B, Fields_Cuda G, CeedScalar *W) {\n";
751 
752   // Scratch buffers
753   for (CeedInt i = 0; i < num_input_fields; i++) {
754     CeedEvalMode eval_mode;
755 
756     CeedCallBackend(CeedQFunctionFieldGetEvalMode(qf_input_fields[i], &eval_mode));
757     if (eval_mode != CEED_EVAL_WEIGHT) {  // Skip CEED_EVAL_WEIGHT
758       code << "  const CeedScalar *d_in_" << i << " = fields.inputs[" << i << "];\n";
759     }
760   }
761   for (CeedInt i = 0; i < num_output_fields; i++) {
762     code << "  CeedScalar *d_out_" << i << " = fields.outputs[" << i << "];\n";
763   }
764 
765   code << "  const CeedInt dim = " << dim << ";\n";
766   code << "  const CeedInt Q_1d = " << Q_1d << ";\n";
767 
768   // Shared data
769   code << "  extern __shared__ CeedScalar slice[];\n";
770   code << "  SharedData_Cuda data;\n";
771   code << "  data.t_id_x = threadIdx.x;\n";
772   code << "  data.t_id_y = threadIdx.y;\n";
773   code << "  data.t_id_z = threadIdx.z;\n";
774   code << "  data.t_id  = threadIdx.x + threadIdx.y*blockDim.x + threadIdx.z*blockDim.y*blockDim.x;\n";
775   code << "  data.slice = slice + data.t_id_z*T_1D" << (dim > 1 ? "*T_1D" : "") << ";\n";
776 
777   // Initialize constants, and matrices B and G
778   code << "\n  // Input field constants and basis data\n";
779   for (CeedInt i = 0; i < num_input_fields; i++) {
780     CeedCallBackend(CeedOperatorBuildKernelFieldData_Cuda_gen(code, data, i, op_input_fields[i], qf_input_fields[i], Q_1d, true, use_3d_slices));
781   }
782   code << "\n  // Output field constants and basis data\n";
783   for (CeedInt i = 0; i < num_output_fields; i++) {
784     CeedCallBackend(CeedOperatorBuildKernelFieldData_Cuda_gen(code, data, i, op_output_fields[i], qf_output_fields[i], Q_1d, false, use_3d_slices));
785   }
786 
787   // Loop over all elements
788   code << "\n  // Element loop\n";
789   code << "  __syncthreads();\n";
790   code << "  for (CeedInt elem = blockIdx.x*blockDim.z + threadIdx.z; elem < num_elem; elem += gridDim.x*blockDim.z) {\n";
791 
792   // -- Input restriction and basis
793   code << "    // -- Input field restrictions and basis actions\n";
794   for (CeedInt i = 0; i < num_input_fields; i++) {
795     code << "    // ---- Input field " << i << "\n";
796 
797     // ---- Restriction
798     CeedCallBackend(
799         CeedOperatorBuildKernelRestriction_Cuda_gen(code, data, i, dim, op_input_fields[i], qf_input_fields[i], Q_1d, true, use_3d_slices));
800 
801     // ---- Basis action
802     CeedCallBackend(CeedOperatorBuildKernelBasis_Cuda_gen(code, data, i, dim, op_input_fields[i], qf_input_fields[i], Q_1d, true, use_3d_slices));
803   }
804 
805   // -- Q function
806   CeedCallBackend(CeedOperatorBuildKernelQFunction_Cuda_gen(code, data, dim, num_input_fields, op_input_fields, qf_input_fields, num_output_fields,
807                                                             op_output_fields, qf_output_fields, qfunction_name, Q_1d, use_3d_slices));
808 
809   // -- Output basis and restriction
810   code << "\n    // -- Output field basis action and restrictions\n";
811   for (CeedInt i = 0; i < num_output_fields; i++) {
812     code << "    // ---- Output field " << i << "\n";
813 
814     // ---- Basis action
815     CeedCallBackend(CeedOperatorBuildKernelBasis_Cuda_gen(code, data, i, dim, op_output_fields[i], qf_output_fields[i], Q_1d, false, use_3d_slices));
816 
817     // ---- Restriction
818     CeedCallBackend(
819         CeedOperatorBuildKernelRestriction_Cuda_gen(code, data, i, dim, op_output_fields[i], qf_output_fields[i], Q_1d, false, use_3d_slices));
820   }
821 
822   // Close loop and function
823   code << "  }\n";
824   code << "}\n";
825   code << "// -----------------------------------------------------------------------------\n\n";
826 
827   // View kernel for debugging
828   CeedDebug256(ceed, CEED_DEBUG_COLOR_SUCCESS, "Generated Operator Kernels:\n");
829   CeedDebug(ceed, code.str().c_str());
830 
831   CeedCallBackend(CeedCompile_Cuda(ceed, code.str().c_str(), &data->module, 1, "T_1D", CeedIntMax(Q_1d, data->max_P_1d)));
832   CeedCallBackend(CeedGetKernel_Cuda(ceed, data->module, operator_name.c_str(), &data->op));
833 
834   CeedCallBackend(CeedOperatorSetSetupDone(op));
835   return CEED_ERROR_SUCCESS;
836 }
837 
838 //------------------------------------------------------------------------------
839