xref: /libCEED/tests/t302-basis.c (revision ad6481ce28fcfada16ee6d8a13bbacd137fe686a)
1 /// @file
2 /// Test Collocated Grad calculated matches basis with Lobatto points
3 /// \test Test Collocated Grad calculated matches basis with Lobatto points
4 #include <ceed.h>
5 #include <ceed/backend.h>
6 #include <math.h>
7 
8 int main(int argc, char **argv) {
9   Ceed              ceed;
10   CeedInt           p = 4;
11   CeedScalar        collocated_gradient_1d[(p + 2) * (p + 2)], x_2[p + 2];
12   const CeedScalar *gradient_1d, *q_ref;
13   CeedScalar        sum = 0.0;
14   CeedBasis         basis;
15 
16   CeedInit(argv[1], &ceed);
17 
18   // Already collocated, GetCollocatedGrad will return grad_1d
19   CeedBasisCreateTensorH1Lagrange(ceed, 1, 1, p, p, CEED_GAUSS_LOBATTO, &basis);
20   CeedBasisGetCollocatedGrad(basis, collocated_gradient_1d);
21   CeedBasisGetGrad(basis, &gradient_1d);
22 
23   for (CeedInt i = 0; i < p; i++) {
24     for (CeedInt j = 0; j < p; j++) {
25       if (fabs(collocated_gradient_1d[j + p * i] - gradient_1d[j + p * i]) > 100 * CEED_EPSILON) {
26         // LCOV_EXCL_START
27         printf("Error in collocated gradient %f != %f\n", collocated_gradient_1d[j + p * i], gradient_1d[j + p * i]);
28         // LCOV_EXCL_START
29       }
30     }
31   }
32   CeedBasisDestroy(&basis);
33 
34   // Q = P, not already collocated
35   CeedBasisCreateTensorH1Lagrange(ceed, 1, 1, p, p, CEED_GAUSS, &basis);
36   CeedBasisGetCollocatedGrad(basis, collocated_gradient_1d);
37 
38   CeedBasisGetQRef(basis, &q_ref);
39   for (CeedInt i = 0; i < p; i++) x_2[i] = q_ref[i] * q_ref[i];
40 
41   // Verify collo_grad * x^2 = 2x for quadrature points
42   for (CeedInt i = 0; i < p; i++) {
43     sum = 0.0;
44     for (CeedInt j = 0; j < p; j++) sum += collocated_gradient_1d[j + p * i] * x_2[j];
45     if (fabs(sum - 2 * q_ref[i]) > 100 * CEED_EPSILON) printf("Error in collocated gradient %f != %f\n", sum, 2 * q_ref[i]);
46   }
47   CeedBasisDestroy(&basis);
48 
49   // Q = P + 2, not already collocated
50   CeedBasisCreateTensorH1Lagrange(ceed, 1, 1, p, p + 2, CEED_GAUSS, &basis);
51   CeedBasisGetCollocatedGrad(basis, collocated_gradient_1d);
52 
53   CeedBasisGetQRef(basis, &q_ref);
54   for (CeedInt i = 0; i < p + 2; i++) x_2[i] = q_ref[i] * q_ref[i];
55 
56   // Verify collocated_gradient * x^2 = 2x for quadrature points
57   for (CeedInt i = 0; i < p + 2; i++) {
58     sum = 0.0;
59     for (CeedInt j = 0; j < p + 2; j++) sum += collocated_gradient_1d[j + (p + 2) * i] * x_2[j];
60     if (fabs(sum - 2 * q_ref[i]) > 100 * CEED_EPSILON) printf("Error in collocated gradient %f != %f\n", sum, 2 * q_ref[i]);
61   }
62   CeedBasisDestroy(&basis);
63 
64   CeedDestroy(&ceed);
65   return 0;
66 }
67