xref: /libCEED/tests/t541-operator.h (revision ce18bed930e8f3bfebcf709a18844aba97fe4630)
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 CEED_QFUNCTION(setup_diff)(void *ctx, const CeedInt Q,
9                            const CeedScalar *const *in,
10                            CeedScalar *const *out) {
11   // in[0] is Jacobians with shape [2, nc=2, Q]
12   // in[1] is quadrature weights, size (Q)
13   const CeedScalar *J = in[0], *w = in[1];
14 
15   // out[0] is qdata, size (Q)
16   CeedScalar *q_data = out[0];
17 
18   // Quadrature point loop
19   CeedPragmaSIMD
20   for (CeedInt i=0; i<Q; i++) {
21     // Qdata stored in Voigt convention
22     // J: 0 2   q_data: 0 2   adj(J):  J22 -J12
23     //    1 3           2 1           -J21  J11
24     const CeedScalar J11 = J[i+Q*0];
25     const CeedScalar J21 = J[i+Q*1];
26     const CeedScalar J12 = J[i+Q*2];
27     const CeedScalar J22 = J[i+Q*3];
28     const CeedScalar qw = w[i] / (J11*J22 - J21*J12);
29     q_data[i+Q*0] =   qw * (J12*J12 + J22*J22);
30     q_data[i+Q*1] =   qw * (J11*J11 + J21*J21);
31     q_data[i+Q*2] = - qw * (J11*J12 + J21*J22);
32   } // End of Quadrature Point Loop
33   return 0;
34 }
35 
36 CEED_QFUNCTION(apply)(void *ctx, const CeedInt Q, const CeedScalar *const *in,
37                       CeedScalar *const *out) {
38   // in[0] is gradient u, shape [2, nc=1, Q]
39   // in[1] is quadrature data, size (3*Q)
40   const CeedScalar *ug = in[0], *q_data = in[1];
41 
42   // out[0] is output to multiply against gradient v, shape [2, nc=1, Q]
43   CeedScalar *vg = out[0];
44 
45   // Quadrature point loop
46   CeedPragmaSIMD
47   for (CeedInt i=0; i<Q; i++) {
48     // Read spatial derivatives of u
49     const CeedScalar du[2]        =  {ug[i+Q*0],
50                                       ug[i+Q*1]
51                                      };
52 
53     // Read qdata (dXdxdXdxT symmetric matrix)
54     // Stored in Voigt convention
55     // 0 2
56     // 2 1
57     // *INDENT-OFF*
58     const CeedScalar dXdxdXdxT[2][2] = {{q_data[i+0*Q],
59                                          q_data[i+2*Q]},
60                                         {q_data[i+2*Q],
61                                          q_data[i+1*Q]}
62                                        };
63     // *INDENT-ON*
64 
65     // Apply Poisson operator
66     // j = direction of vg
67     for (int j=0; j<2; j++)
68       vg[i+j*Q] = (du[0] * dXdxdXdxT[0][j] +
69                    du[1] * dXdxdXdxT[1][j]);
70   } // End of Quadrature Point Loop
71   return 0;
72 }
73