xref: /libCEED/tests/t541-operator.h (revision 947f93aa7135eb1759bf2866bd2fbd481436b113)
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 #include <ceed.h>
9 
10 CEED_QFUNCTION(setup_diff)(void *ctx, const CeedInt Q,
11                            const CeedScalar *const *in,
12                            CeedScalar *const *out) {
13   // in[0] is Jacobians with shape [2, nc=2, Q]
14   // in[1] is quadrature weights, size (Q)
15   const CeedScalar *J = in[0], *w = in[1];
16 
17   // out[0] is qdata, size (Q)
18   CeedScalar *q_data = out[0];
19 
20   // Quadrature point loop
21   CeedPragmaSIMD
22   for (CeedInt i=0; i<Q; i++) {
23     // Qdata stored in Voigt convention
24     // J: 0 2   q_data: 0 2   adj(J):  J22 -J12
25     //    1 3           2 1           -J21  J11
26     const CeedScalar J11 = J[i+Q*0];
27     const CeedScalar J21 = J[i+Q*1];
28     const CeedScalar J12 = J[i+Q*2];
29     const CeedScalar J22 = J[i+Q*3];
30     const CeedScalar qw = w[i] / (J11*J22 - J21*J12);
31     q_data[i+Q*0] =   qw * (J12*J12 + J22*J22);
32     q_data[i+Q*1] =   qw * (J11*J11 + J21*J21);
33     q_data[i+Q*2] = - qw * (J11*J12 + J21*J22);
34   } // End of Quadrature Point Loop
35   return 0;
36 }
37 
38 CEED_QFUNCTION(apply)(void *ctx, const CeedInt Q, const CeedScalar *const *in,
39                       CeedScalar *const *out) {
40   // in[0] is gradient u, shape [2, nc=1, Q]
41   // in[1] is quadrature data, size (3*Q)
42   const CeedScalar *ug = in[0], *q_data = in[1];
43 
44   // out[0] is output to multiply against gradient v, shape [2, nc=1, Q]
45   CeedScalar *vg = out[0];
46 
47   // Quadrature point loop
48   CeedPragmaSIMD
49   for (CeedInt i=0; i<Q; i++) {
50     // Read spatial derivatives of u
51     const CeedScalar du[2]        =  {ug[i+Q*0],
52                                       ug[i+Q*1]
53                                      };
54 
55     // Read qdata (dXdxdXdxT symmetric matrix)
56     // Stored in Voigt convention
57     // 0 2
58     // 2 1
59     // *INDENT-OFF*
60     const CeedScalar dXdxdXdxT[2][2] = {{q_data[i+0*Q],
61                                          q_data[i+2*Q]},
62                                         {q_data[i+2*Q],
63                                          q_data[i+1*Q]}
64                                        };
65     // *INDENT-ON*
66 
67     // Apply Poisson operator
68     // j = direction of vg
69     for (int j=0; j<2; j++)
70       vg[i+j*Q] = (du[0] * dXdxdXdxT[0][j] +
71                    du[1] * dXdxdXdxT[1][j]);
72   } // End of Quadrature Point Loop
73   return 0;
74 }
75