xref: /libCEED/include/ceed/jit-source/gallery/ceed-poisson2dbuild.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 2D Poisson operator
10 **/
11 
12 #ifndef poisson2dbuild_h
13 #define poisson2dbuild_h
14 
15 #include <ceed.h>
16 
17 CEED_QFUNCTION(Poisson2DBuild)(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
19   // the symmetric part of the result.
20   // *INDENT-OFF*
21   // in[0] is Jacobians with shape [2, nc=2, Q]
22   // in[1] is quadrature weights, size (Q)
23   const CeedScalar(*J)[2][CEED_Q_VLA] = (const CeedScalar(*)[2][CEED_Q_VLA])in[0], *w = in[1];
24   // out[0] is qdata, size (3*Q)
25   CeedScalar(*q_data)[CEED_Q_VLA] = (CeedScalar(*)[CEED_Q_VLA])out[0];
26   // *INDENT-ON*
27 
28   // Quadrature point loop
29   CeedPragmaSIMD for (CeedInt i = 0; i < Q; i++) {
30     // Qdata stored in Voigt convention
31     // J: 0 2   q_data: 0 2   adj(J):  J11 -J01
32     //    1 3           2 1           -J10  J00
33     const CeedScalar J00 = J[0][0][i];
34     const CeedScalar J10 = J[0][1][i];
35     const CeedScalar J01 = J[1][0][i];
36     const CeedScalar J11 = J[1][1][i];
37     const CeedScalar qw  = w[i] / (J00 * J11 - J10 * J01);
38     q_data[0][i]         = qw * (J01 * J01 + J11 * J11);
39     q_data[1][i]         = qw * (J00 * J00 + J10 * J10);
40     q_data[2][i]         = -qw * (J00 * J01 + J10 * J11);
41   }  // End of Quadrature Point Loop
42 
43   return CEED_ERROR_SUCCESS;
44 }
45 
46 #endif  // poisson2dbuild_h
47