xref: /libCEED/include/ceed/jit-source/gallery/ceed-poisson3dbuild.h (revision 13f28a1f297c33230ed3196f9946aaac3811bd77)
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 operator
10 **/
11 
12 #ifndef poisson3dbuild_h
13 #define poisson3dbuild_h
14 
15 #include <ceed.h>
16 
17 CEED_QFUNCTION(Poisson3DBuild)(void *ctx, const CeedInt Q, const CeedScalar *const *in, CeedScalar *const *out) {
18   // At every quadrature point, compute w/det(J).adj(J).adj(J)^T and store the symmetric part of the result.
19   // in[0] is Jacobians with shape [3, nc=3, Q]
20   // in[1] is quadrature weights, size (Q)
21   const CeedScalar(*J)[3][CEED_Q_VLA] = (const CeedScalar(*)[3][CEED_Q_VLA])in[0], *w = in[1];
22   // out[0] is qdata, size (6*Q)
23   CeedScalar(*q_data)[CEED_Q_VLA] = (CeedScalar(*)[CEED_Q_VLA])out[0];
24 
25   const CeedInt dim = 3;
26 
27   // Quadrature point loop
28   CeedPragmaSIMD for (CeedInt i = 0; i < Q; i++) {
29     // Compute the adjoint
30     CeedScalar A[3][3];
31     for (CeedInt j = 0; j < dim; j++)
32       for (CeedInt k = 0; k < dim; k++)
33         // Equivalent code with no mod operations:
34         // A[k][j] = J[k+1][j+1]*J[k+2][j+2] - J[k+2][j+1]*J[k+1][j+2]
35         A[k][j] = J[(k + 1) % dim][(j + 1) % dim][i] * J[(k + 2) % dim][(j + 2) % dim][i] -
36                   J[(k + 2) % dim][(j + 1) % dim][i] * J[(k + 1) % dim][(j + 2) % dim][i];
37 
38     // Compute quadrature weight / det(J)
39     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]);
40 
41     // Compute geometric factors
42     // Stored in Voigt convention
43     // 0 5 4
44     // 5 1 3
45     // 4 3 2
46     q_data[0][i] = qw * (A[0][0] * A[0][0] + A[0][1] * A[0][1] + A[0][2] * A[0][2]);
47     q_data[1][i] = qw * (A[1][0] * A[1][0] + A[1][1] * A[1][1] + A[1][2] * A[1][2]);
48     q_data[2][i] = qw * (A[2][0] * A[2][0] + A[2][1] * A[2][1] + A[2][2] * A[2][2]);
49     q_data[3][i] = qw * (A[1][0] * A[2][0] + A[1][1] * A[2][1] + A[1][2] * A[2][2]);
50     q_data[4][i] = qw * (A[0][0] * A[2][0] + A[0][1] * A[2][1] + A[0][2] * A[2][2]);
51     q_data[5][i] = qw * (A[0][0] * A[1][0] + A[0][1] * A[1][1] + A[0][2] * A[1][2]);
52   }  // End of Quadrature Point Loop
53 
54   return CEED_ERROR_SUCCESS;
55 }
56 
57 #endif  // poisson3dbuild_h
58