xref: /libCEED/rust/libceed-sys/c-src/backends/ref/ceed-ref-basis.c (revision a8de75f0ba69dfecd93c7d0093c041c0285ffd21)
1 // Copyright (c) 2017-2018, Lawrence Livermore National Security, LLC.
2 // Produced at the Lawrence Livermore National Laboratory. LLNL-CODE-734707.
3 // All Rights reserved. See files LICENSE and NOTICE for details.
4 //
5 // This file is part of CEED, a collection of benchmarks, miniapps, software
6 // libraries and APIs for efficient high-order finite element and spectral
7 // element discretizations for exascale applications. For more information and
8 // source code availability see http://github.com/ceed.
9 //
10 // The CEED research is supported by the Exascale Computing Project 17-SC-20-SC,
11 // a collaborative effort of two U.S. Department of Energy organizations (Office
12 // of Science and the National Nuclear Security Administration) responsible for
13 // the planning and preparation of a capable exascale ecosystem, including
14 // software, applications, hardware, advanced system engineering and early
15 // testbed platforms, in support of the nation's exascale computing imperative.
16 
17 #include <ceed-impl.h>
18 #include <string.h>
19 #include "ceed-ref.h"
20 
21 // Contracts on the middle index
22 // NOTRANSPOSE: V_ajc = T_jb U_abc
23 // TRANSPOSE:   V_ajc = T_bj U_abc
24 // If Add != 0, "=" is replaced by "+="
25 static int CeedTensorContract_Ref(Ceed ceed,
26                                   CeedInt A, CeedInt B, CeedInt C, CeedInt J,
27                                   const CeedScalar *restrict t, CeedTransposeMode tmode,
28                                   const CeedInt Add,
29                                   const CeedScalar *restrict u, CeedScalar *restrict v) {
30   CeedInt tstride0 = B, tstride1 = 1;
31   if (tmode == CEED_TRANSPOSE) {
32     tstride0 = 1; tstride1 = J;
33   }
34 
35   if (!Add)
36     for (CeedInt q=0; q<A*J*C; q++)
37       v[q] = (CeedScalar) 0.0;
38 
39   for (CeedInt a=0; a<A; a++)
40     for (CeedInt b=0; b<B; b++)
41       for (CeedInt j=0; j<J; j++) {
42         CeedScalar tq = t[j*tstride0 + b*tstride1];
43         for (CeedInt c=0; c<C; c++)
44           v[(a*J+j)*C+c] += tq * u[(a*B+b)*C+c];
45       }
46   return 0;
47 }
48 
49 static int CeedBasisApply_Ref(CeedBasis basis, CeedInt nelem,
50                               CeedTransposeMode tmode, CeedEvalMode emode,
51                               const CeedScalar *u, CeedScalar *v) {
52   int ierr;
53   const CeedInt dim = basis->dim;
54   const CeedInt ncomp = basis->ncomp;
55   CeedInt nqpt;
56   ierr = CeedBasisGetNumQuadraturePoints(basis, &nqpt); CeedChk(ierr);
57   CeedInt ndof;
58   ierr = CeedBasisGetNumNodes(basis, &ndof); CeedChk(ierr);
59   const CeedInt add = (tmode == CEED_TRANSPOSE);
60 
61   if (nelem != 1)
62     return CeedError(basis->ceed, 1,
63                      "This backend does not support BasisApply for multiple elements");
64 
65   // Clear v if operating in transpose
66   if (tmode == CEED_TRANSPOSE) {
67     const CeedInt vsize = ncomp*ndof;
68     for (CeedInt i = 0; i < vsize; i++)
69       v[i] = (CeedScalar) 0;
70   }
71   // Tensor basis
72   if (basis->tensorbasis) {
73     switch (emode) {
74     // Interpolate to/from quadrature points
75     case CEED_EVAL_INTERP: {
76       CeedInt P = basis->P1d, Q = basis->Q1d;
77       if (tmode == CEED_TRANSPOSE) {
78         P = basis->Q1d; Q = basis->P1d;
79       }
80       CeedInt pre = ncomp*CeedIntPow(P, dim-1), post = 1;
81       CeedScalar tmp[2][ncomp*Q*CeedIntPow(P>Q?P:Q, dim-1)];
82       for (CeedInt d=0; d<dim; d++) {
83         ierr = CeedTensorContract_Ref(basis->ceed, pre, P, post, Q, basis->interp1d,
84                                       tmode, add&&(d==dim-1),
85                                       d==0?u:tmp[d%2], d==dim-1?v:tmp[(d+1)%2]);
86         CeedChk(ierr);
87         pre /= P;
88         post *= Q;
89       }
90     } break;
91     // Evaluate the gradient to/from quadrature points
92     case CEED_EVAL_GRAD: {
93       CeedInt P = basis->P1d, Q = basis->Q1d;
94       // In CEED_NOTRANSPOSE mode:
95       // u has shape [dim, ncomp, P^dim, nelem], row-major layout
96       // v has shape [dim, ncomp, Q^dim, nelem], row-major layout
97       // In CEED_TRANSPOSE mode, the sizes of u and v are switched.
98       if (tmode == CEED_TRANSPOSE) {
99         P = basis->Q1d, Q = basis->P1d;
100       }
101       CeedScalar tmp[2][ncomp*Q*CeedIntPow(P>Q?P:Q, dim-1)];
102       for (CeedInt p = 0; p < dim; p++) {
103         CeedInt pre = ncomp*CeedIntPow(P, dim-1), post = 1;
104         for (CeedInt d=0; d<dim; d++) {
105           ierr = CeedTensorContract_Ref(basis->ceed, pre, P, post, Q,
106                                         (p==d)?basis->grad1d:basis->interp1d,
107                                         tmode, add&&(d==dim-1),
108                                         (d == 0
109                                          ? (tmode==CEED_NOTRANSPOSE?u:u+p*ncomp*nqpt)
110                                          : tmp[d%2]),
111                                         (d == dim-1
112                                          ? (tmode==CEED_TRANSPOSE?v:v+p*ncomp*nqpt)
113                                          : tmp[(d+1)%2]));
114           CeedChk(ierr);
115           pre /= P;
116           post *= Q;
117         }
118       }
119     } break;
120     // Retrieve interpolation weights
121     case CEED_EVAL_WEIGHT: {
122       if (tmode == CEED_TRANSPOSE)
123         return CeedError(basis->ceed, 1,
124                          "CEED_EVAL_WEIGHT incompatible with CEED_TRANSPOSE");
125       CeedInt Q = basis->Q1d;
126       for (CeedInt d=0; d<dim; d++) {
127         CeedInt pre = CeedIntPow(Q, dim-d-1), post = CeedIntPow(Q, d);
128         for (CeedInt i=0; i<pre; i++)
129           for (CeedInt j=0; j<Q; j++)
130             for (CeedInt k=0; k<post; k++)
131               v[(i*Q + j)*post + k] = basis->qweight1d[j]
132                                       * (d == 0 ? 1 : v[(i*Q + j)*post + k]);
133       }
134     } break;
135     // Evaluate the divergence to/from the quadrature points
136     case CEED_EVAL_DIV:
137       return CeedError(basis->ceed, 1, "CEED_EVAL_DIV not supported");
138     // Evaluate the curl to/from the quadrature points
139     case CEED_EVAL_CURL:
140       return CeedError(basis->ceed, 1, "CEED_EVAL_CURL not supported");
141     // Take no action, BasisApply should not have been called
142     case CEED_EVAL_NONE:
143       return CeedError(basis->ceed, 1,
144                        "CEED_EVAL_NONE does not make sense in this context");
145     }
146   } else {
147     // Non-tensor basis
148     switch (emode) {
149     case CEED_EVAL_INTERP: {
150       CeedInt P = basis->P, Q = basis->Q;
151       if (tmode == CEED_TRANSPOSE) {
152         P = basis->Q; Q = basis->P;
153       }
154       ierr = CeedTensorContract_Ref(basis->ceed, ncomp, P, 1, Q, basis->interp1d,
155                                     tmode, add, u, v);
156       CeedChk(ierr);
157     }
158     break;
159     case CEED_EVAL_GRAD: {
160       CeedInt P = basis->P, Q = dim*basis->Q;
161       if (tmode == CEED_TRANSPOSE) {
162         P = dim*basis->Q; Q = basis->P;
163       }
164       ierr = CeedTensorContract_Ref(basis->ceed, ncomp, P, 1, Q, basis->grad1d,
165                                     tmode, add, u, v);
166       CeedChk(ierr);
167     }
168     break;
169     case CEED_EVAL_WEIGHT: {
170       if (tmode == CEED_TRANSPOSE)
171         return CeedError(basis->ceed, 1,
172                          "CEED_EVAL_WEIGHT incompatible with CEED_TRANSPOSE");
173       for (CeedInt i=0; i<nqpt; i++)
174         v[i] = basis->qweight1d[i];
175     } break;
176     case CEED_EVAL_DIV:
177       return CeedError(basis->ceed, 1, "CEED_EVAL_DIV not supported");
178     case CEED_EVAL_CURL:
179       return CeedError(basis->ceed, 1, "CEED_EVAL_CURL not supported");
180     case CEED_EVAL_NONE:
181       return CeedError(basis->ceed, 1,
182                        "CEED_EVAL_NONE does not make sense in this context");
183     }
184   }
185   return 0;
186 }
187 
188 static int CeedBasisDestroy_Ref(CeedBasis basis) {
189   return 0;
190 }
191 
192 int CeedBasisCreateTensorH1_Ref(Ceed ceed, CeedInt dim, CeedInt P1d,
193                                 CeedInt Q1d, const CeedScalar *interp1d,
194                                 const CeedScalar *grad1d,
195                                 const CeedScalar *qref1d,
196                                 const CeedScalar *qweight1d,
197                                 CeedBasis basis) {
198   basis->Apply = CeedBasisApply_Ref;
199   basis->Destroy = CeedBasisDestroy_Ref;
200   return 0;
201 }
202 
203 int CeedBasisCreateH1_Ref(Ceed ceed, CeedElemTopology topo, CeedInt dim,
204                           CeedInt ndof, CeedInt nqpts,
205                           const CeedScalar *interp,
206                           const CeedScalar *grad,
207                           const CeedScalar *qref,
208                           const CeedScalar *qweight,
209                           CeedBasis basis) {
210   basis->Apply = CeedBasisApply_Ref;
211   basis->Destroy = CeedBasisDestroy_Ref;
212   return 0;
213 }
214