xref: /libCEED/include/ceed/jit-source/gallery/ceed-poisson3dbuild.h (revision 2b730f8b5a9c809740a0b3b302db43a719c636b1)
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 /**
9   @brief Ceed QFunction for building the geometric data for the 3D Poisson
10            operator
11 **/
12 
13 #ifndef poisson3dbuild_h
14 #define poisson3dbuild_h
15 
16 #include <ceed.h>
17 
18 CEED_QFUNCTION(Poisson3DBuild)(void *ctx, const CeedInt Q, const CeedScalar *const *in, CeedScalar *const *out) {
19   // At every quadrature point, compute w/det(J).adj(J).adj(J)^T and store
20   // the symmetric part of the result.
21   // *INDENT-OFF*
22   // in[0] is Jacobians with shape [3, nc=3, Q]
23   // in[1] is quadrature weights, size (Q)
24   const CeedScalar(*J)[3][CEED_Q_VLA] = (const CeedScalar(*)[3][CEED_Q_VLA])in[0], *w = in[1];
25   // out[0] is qdata, size (6*Q)
26   CeedScalar(*q_data)[CEED_Q_VLA] = (CeedScalar(*)[CEED_Q_VLA])out[0];
27   // *INDENT-ON*
28 
29   const CeedInt dim = 3;
30 
31   // Quadrature point loop
32   CeedPragmaSIMD for (CeedInt i = 0; i < Q; i++) {
33     // Compute the adjoint
34     CeedScalar A[3][3];
35     for (CeedInt j = 0; j < dim; j++)
36       for (CeedInt k = 0; k < dim; k++)
37         // Equivalent code with no mod operations:
38         // A[k][j] = J[k+1][j+1]*J[k+2][j+2] - J[k+2][j+1]*J[k+1][j+2]
39         A[k][j] = J[(k + 1) % dim][(j + 1) % dim][i] * J[(k + 2) % dim][(j + 2) % dim][i] -
40                   J[(k + 2) % dim][(j + 1) % dim][i] * J[(k + 1) % dim][(j + 2) % dim][i];
41 
42     // Compute quadrature weight / det(J)
43     const CeedScalar qw = w[i] / (J[0][0][i] * A[0][0] + J[0][1][i] * A[0][1] + J[0][2][i] * A[0][2]);
44 
45     // Compute geometric factors
46     // Stored in Voigt convention
47     // 0 5 4
48     // 5 1 3
49     // 4 3 2
50     q_data[0][i] = qw * (A[0][0] * A[0][0] + A[0][1] * A[0][1] + A[0][2] * A[0][2]);
51     q_data[1][i] = qw * (A[1][0] * A[1][0] + A[1][1] * A[1][1] + A[1][2] * A[1][2]);
52     q_data[2][i] = qw * (A[2][0] * A[2][0] + A[2][1] * A[2][1] + A[2][2] * A[2][2]);
53     q_data[3][i] = qw * (A[1][0] * A[2][0] + A[1][1] * A[2][1] + A[1][2] * A[2][2]);
54     q_data[4][i] = qw * (A[0][0] * A[2][0] + A[0][1] * A[2][1] + A[0][2] * A[2][2]);
55     q_data[5][i] = qw * (A[0][0] * A[1][0] + A[0][1] * A[1][1] + A[0][2] * A[1][2]);
56   }  // End of Quadrature Point Loop
57 
58   return CEED_ERROR_SUCCESS;
59 }
60 
61 #endif  // poisson3dbuild_h
62