xref: /libCEED/tests/t330-basis.h (revision 4fee36f0a30516a0b5ad51bf7eb3b32d83efd623)
13d8e8822SJeremy L Thompson // Copyright (c) 2017-2022, Lawrence Livermore National Security, LLC and other CEED contributors.
23d8e8822SJeremy L Thompson // All Rights Reserved. See the top-level LICENSE and NOTICE files for details.
350c301a5SRezgar Shakeri //
43d8e8822SJeremy L Thompson // SPDX-License-Identifier: BSD-2-Clause
550c301a5SRezgar Shakeri //
63d8e8822SJeremy L Thompson // This file is part of CEED:  http://github.com/ceed
750c301a5SRezgar Shakeri 
82b730f8bSJeremy L Thompson #include <ceed.h>
92b730f8bSJeremy L Thompson 
1050c301a5SRezgar Shakeri // Hdiv basis for quadrilateral linear BDM element in 2D
11*4fee36f0SJeremy L Thompson // Local numbering is as follow (each edge has 2 vector DoF)
1250c301a5SRezgar Shakeri //     b4     b5
1350c301a5SRezgar Shakeri //    2---------3
1450c301a5SRezgar Shakeri //  b7|         |b3
1550c301a5SRezgar Shakeri //    |         |
1650c301a5SRezgar Shakeri //  b6|         |b2
1750c301a5SRezgar Shakeri //    0---------1
1850c301a5SRezgar Shakeri //     b0     b1
1950c301a5SRezgar Shakeri // Bx[0-->7] = b0_x-->b7_x, By[0-->7] = b0_y-->b7_y
2050c301a5SRezgar Shakeri // To see how the nodal basis is constructed visit:
2150c301a5SRezgar Shakeri // https://github.com/rezgarshakeri/H-div-Tests
22*4fee36f0SJeremy L Thompson int BuildNodalHdivQuadrilateral(CeedScalar *x, CeedScalar *Bx, CeedScalar *By) {
23*4fee36f0SJeremy L Thompson   CeedScalar x_hat = x[0];
24*4fee36f0SJeremy L Thompson   CeedScalar y_hat = x[1];
2550c301a5SRezgar Shakeri   Bx[0]            = -0.125 + 0.125 * x_hat * x_hat;
2650c301a5SRezgar Shakeri   By[0]            = -0.25 + 0.25 * x_hat + 0.25 * y_hat + -0.25 * x_hat * y_hat;
2750c301a5SRezgar Shakeri   Bx[1]            = 0.125 + -0.125 * x_hat * x_hat;
2850c301a5SRezgar Shakeri   By[1]            = -0.25 + -0.25 * x_hat + 0.25 * y_hat + 0.25 * x_hat * y_hat;
2950c301a5SRezgar Shakeri   Bx[2]            = 0.25 + 0.25 * x_hat + -0.25 * y_hat + -0.25 * x_hat * y_hat;
3050c301a5SRezgar Shakeri   By[2]            = -0.125 + 0.125 * y_hat * y_hat;
3150c301a5SRezgar Shakeri   Bx[3]            = 0.25 + 0.25 * x_hat + 0.25 * y_hat + 0.25 * x_hat * y_hat;
3250c301a5SRezgar Shakeri   By[3]            = 0.125 + -0.125 * y_hat * y_hat;
3350c301a5SRezgar Shakeri   Bx[4]            = -0.125 + 0.125 * x_hat * x_hat;
3450c301a5SRezgar Shakeri   By[4]            = 0.25 + -0.25 * x_hat + 0.25 * y_hat + -0.25 * x_hat * y_hat;
3550c301a5SRezgar Shakeri   Bx[5]            = 0.125 + -0.125 * x_hat * x_hat;
3650c301a5SRezgar Shakeri   By[5]            = 0.25 + 0.25 * x_hat + 0.25 * y_hat + 0.25 * x_hat * y_hat;
3750c301a5SRezgar Shakeri   Bx[6]            = -0.25 + 0.25 * x_hat + 0.25 * y_hat + -0.25 * x_hat * y_hat;
3850c301a5SRezgar Shakeri   By[6]            = -0.125 + 0.125 * y_hat * y_hat;
3950c301a5SRezgar Shakeri   Bx[7]            = -0.25 + 0.25 * x_hat + -0.25 * y_hat + 0.25 * x_hat * y_hat;
4050c301a5SRezgar Shakeri   By[7]            = 0.125 + -0.125 * y_hat * y_hat;
4150c301a5SRezgar Shakeri   return 0;
4250c301a5SRezgar Shakeri }
43*4fee36f0SJeremy L Thompson static void BuildHdivQuadrilateral(CeedInt q, CeedScalar *q_ref, CeedScalar *q_weights, CeedScalar *interp, CeedScalar *div, CeedQuadMode quad_mode) {
4450c301a5SRezgar Shakeri   // Get 1D quadrature on [-1,1]
45*4fee36f0SJeremy L Thompson   CeedScalar q_ref_1d[q], q_weight_1d[q];
4650c301a5SRezgar Shakeri   switch (quad_mode) {
4750c301a5SRezgar Shakeri     case CEED_GAUSS:
48*4fee36f0SJeremy L Thompson       CeedGaussQuadrature(q, q_ref_1d, q_weight_1d);
4950c301a5SRezgar Shakeri       break;
5059058f14SJeremy L Thompson     // LCOV_EXCL_START
5150c301a5SRezgar Shakeri     case CEED_GAUSS_LOBATTO:
52*4fee36f0SJeremy L Thompson       CeedLobattoQuadrature(q, q_ref_1d, q_weight_1d);
5350c301a5SRezgar Shakeri       break;
5450c301a5SRezgar Shakeri   }
5559058f14SJeremy L Thompson   // LCOV_EXCL_STOP
5650c301a5SRezgar Shakeri 
5750c301a5SRezgar Shakeri   // Divergence operator; Divergence of nodal basis for ref element
5850c301a5SRezgar Shakeri   CeedScalar D[8] = {0.25, 0.25, 0.25, 0.25, 0.25, 0.25, 0.25, 0.25};
5950c301a5SRezgar Shakeri   // Loop over quadrature points
6050c301a5SRezgar Shakeri   CeedScalar Bx[8], By[8];
6150c301a5SRezgar Shakeri   CeedScalar X[2];
6250c301a5SRezgar Shakeri 
63*4fee36f0SJeremy L Thompson   for (CeedInt i = 0; i < q; i++) {
64*4fee36f0SJeremy L Thompson     for (CeedInt j = 0; j < q; j++) {
65*4fee36f0SJeremy L Thompson       CeedInt k1        = q * i + j;
6650c301a5SRezgar Shakeri       q_ref[k1]         = q_ref_1d[j];
67*4fee36f0SJeremy L Thompson       q_ref[k1 + q * q] = q_ref_1d[i];
6850c301a5SRezgar Shakeri       q_weights[k1]     = q_weight_1d[j] * q_weight_1d[i];
6950c301a5SRezgar Shakeri       X[0]              = q_ref_1d[j];
7050c301a5SRezgar Shakeri       X[1]              = q_ref_1d[i];
71*4fee36f0SJeremy L Thompson       BuildNodalHdivQuadrilateral(X, Bx, By);
7250c301a5SRezgar Shakeri       for (CeedInt k = 0; k < 8; k++) {
7350c301a5SRezgar Shakeri         interp[k1 * 8 + k]             = Bx[k];
74*4fee36f0SJeremy L Thompson         interp[k1 * 8 + k + 8 * q * q] = By[k];
7550c301a5SRezgar Shakeri         div[k1 * 8 + k]                = D[k];
7650c301a5SRezgar Shakeri       }
7750c301a5SRezgar Shakeri     }
7850c301a5SRezgar Shakeri   }
7950c301a5SRezgar Shakeri }