xref: /libCEED/examples/petsc/qfunctions/bps/bp1.h (revision caee03026e6576cbf7a399c2fc51bb918c77f451)
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 /// @file
9 /// libCEED QFunctions for mass operator example using PETSc
10 
11 #ifndef bp1_h
12 #define bp1_h
13 
14 #include <ceed.h>
15 #include <math.h>
16 
17 // -----------------------------------------------------------------------------
18 // This QFunction sets up the geometric factors required to apply the
19 //   mass operator
20 //
21 // The quadrature data is stored in the array q_data.
22 //
23 // We require the determinant of the Jacobian to properly compute integrals of
24 //   the form: int( u v )
25 //
26 // Qdata: det_J * w
27 //
28 // -----------------------------------------------------------------------------
29 CEED_QFUNCTION(SetupMassGeo)(void *ctx, const CeedInt Q, const CeedScalar *const *in, CeedScalar *const *out) {
30   // Inputs
31   const CeedScalar(*J)[3][CEED_Q_VLA] = (const CeedScalar(*)[3][CEED_Q_VLA])in[1];
32   const CeedScalar(*w)                = in[2];  // Note: *X = in[0]
33   // Outputs
34   CeedScalar *q_data = out[0];
35 
36   const CeedInt dim = 3;
37   // Quadrature Point Loop
38   CeedPragmaSIMD for (CeedInt i = 0; i < Q; i++) {
39     // Setup
40     CeedScalar A[3][3];
41     for (CeedInt j = 0; j < dim; j++) {
42       for (CeedInt k = 0; k < dim; k++) {
43         // Equivalent code with no mod operations:
44         // A[k][j] = J[k+1][j+1]*J[k+2][j+2] - J[k+1][j+2]*J[k+2][j+1]
45         A[k][j] = J[(k + 1) % dim][(j + 1) % dim][i] * J[(k + 2) % dim][(j + 2) % dim][i] -
46                   J[(k + 1) % dim][(j + 2) % dim][i] * J[(k + 2) % dim][(j + 1) % dim][i];
47       }
48     }
49     const CeedScalar detJ = J[0][0][i] * A[0][0] + J[0][1][i] * A[0][1] + J[0][2][i] * A[0][2];
50     q_data[i]             = detJ * w[i];
51   }  // End of Quadrature Point Loop
52   return 0;
53 }
54 
55 // -----------------------------------------------------------------------------
56 // This QFunction sets up the rhs and true solution for the problem
57 // -----------------------------------------------------------------------------
58 CEED_QFUNCTION(SetupMassRhs)(void *ctx, const CeedInt Q, const CeedScalar *const *in, CeedScalar *const *out) {
59   const CeedScalar *x = in[0], *w = in[1];
60   CeedScalar       *true_soln = out[0], *rhs = out[1];
61 
62   // Quadrature Point Loop
63   CeedPragmaSIMD for (CeedInt i = 0; i < Q; i++) {
64     true_soln[i] = sqrt(x[i] * x[i] + x[i + Q] * x[i + Q] + x[i + 2 * Q] * x[i + 2 * Q]);
65     rhs[i]       = w[i] * true_soln[i];
66   }  // End of Quadrature Point Loop
67   return 0;
68 }
69 
70 // -----------------------------------------------------------------------------
71 // This QFunction applies the mass operator for a scalar field.
72 //
73 // Inputs:
74 //   u     - Input vector at quadrature points
75 //   q_data - Geometric factors
76 //
77 // Output:
78 //   v     - Output vector (test functions) at quadrature points
79 //
80 // -----------------------------------------------------------------------------
81 CEED_QFUNCTION(Mass)(void *ctx, const CeedInt Q, const CeedScalar *const *in, CeedScalar *const *out) {
82   const CeedScalar *u = in[0], *q_data = in[1];
83   CeedScalar       *v = out[0];
84 
85   // Quadrature Point Loop
86   CeedPragmaSIMD for (CeedInt i = 0; i < Q; i++) v[i] = q_data[i] * u[i];
87 
88   return 0;
89 }
90 // -----------------------------------------------------------------------------
91 
92 #endif  // bp1_h
93