xref: /libCEED/tests/t303-basis.c (revision 57c64913cb6f06c2f6a40825dd942ceba0d2fe12)
1*57c64913Sjeremylt // Test interpolation in multiple dimensions
2*57c64913Sjeremylt #include <ceed.h>
3*57c64913Sjeremylt #include <math.h>
4*57c64913Sjeremylt 
5*57c64913Sjeremylt static CeedScalar Eval(CeedInt dim, const CeedScalar x[]) {
6*57c64913Sjeremylt   CeedScalar result = 1, center = 0.1;
7*57c64913Sjeremylt   for (CeedInt d=0; d<dim; d++) {
8*57c64913Sjeremylt     result *= tanh(x[d] - center);
9*57c64913Sjeremylt     center += 0.1;
10*57c64913Sjeremylt   }
11*57c64913Sjeremylt   return result;
12*57c64913Sjeremylt }
13*57c64913Sjeremylt 
14*57c64913Sjeremylt int main(int argc, char **argv) {
15*57c64913Sjeremylt   Ceed ceed;
16*57c64913Sjeremylt 
17*57c64913Sjeremylt   CeedInit(argv[1], &ceed);
18*57c64913Sjeremylt   for (CeedInt dim=1; dim<=3; dim++) {
19*57c64913Sjeremylt     CeedBasis bxl, bul, bxg, bug;
20*57c64913Sjeremylt     CeedInt Q = 10, Qdim = CeedPowInt(Q, dim), Xdim = CeedPowInt(2, dim);
21*57c64913Sjeremylt     CeedScalar x[Xdim*dim];
22*57c64913Sjeremylt     CeedScalar xq[Qdim*dim], uq[Qdim], u[Qdim];
23*57c64913Sjeremylt 
24*57c64913Sjeremylt     for (CeedInt d=0; d<dim; d++) {
25*57c64913Sjeremylt       for (CeedInt i=0; i<Xdim; i++) {
26*57c64913Sjeremylt         x[d*Xdim + i] = (i % CeedPowInt(2, dim-d)) / CeedPowInt(2, dim-d-1) ? 1 : -1;
27*57c64913Sjeremylt       }
28*57c64913Sjeremylt     }
29*57c64913Sjeremylt     CeedBasisCreateTensorH1Lagrange(ceed, dim, dim, 2, Q, CEED_GAUSS_LOBATTO, &bxl);
30*57c64913Sjeremylt     CeedBasisCreateTensorH1Lagrange(ceed, dim, 1, Q, Q, CEED_GAUSS_LOBATTO, &bul);
31*57c64913Sjeremylt     CeedBasisApply(bxl, 1, CEED_NOTRANSPOSE, CEED_EVAL_INTERP, x, xq);
32*57c64913Sjeremylt     for (CeedInt i=0; i<Qdim; i++) {
33*57c64913Sjeremylt       CeedScalar xx[dim];
34*57c64913Sjeremylt       for (CeedInt d=0; d<dim; d++) xx[d] = xq[d*Qdim + i];
35*57c64913Sjeremylt       uq[i] = Eval(dim, xx);
36*57c64913Sjeremylt     }
37*57c64913Sjeremylt 
38*57c64913Sjeremylt     // This operation is the identity because the quadrature is collocated
39*57c64913Sjeremylt     CeedBasisApply(bul, 1, CEED_TRANSPOSE, CEED_EVAL_INTERP, uq, u);
40*57c64913Sjeremylt 
41*57c64913Sjeremylt     CeedBasisCreateTensorH1Lagrange(ceed, dim, dim, 2, Q, CEED_GAUSS, &bxg);
42*57c64913Sjeremylt     CeedBasisCreateTensorH1Lagrange(ceed, dim, 1, Q, Q, CEED_GAUSS, &bug);
43*57c64913Sjeremylt     CeedBasisApply(bxg, 1, CEED_NOTRANSPOSE, CEED_EVAL_INTERP, x, xq);
44*57c64913Sjeremylt     CeedBasisApply(bug, 1, CEED_NOTRANSPOSE, CEED_EVAL_INTERP, u, uq);
45*57c64913Sjeremylt     for (CeedInt i=0; i<Qdim; i++) {
46*57c64913Sjeremylt       CeedScalar xx[dim];
47*57c64913Sjeremylt       for (CeedInt d=0; d<dim; d++) xx[d] = xq[d*Qdim + i];
48*57c64913Sjeremylt       CeedScalar fx = Eval(dim, xx);
49*57c64913Sjeremylt       if (!(fabs(uq[i] - fx) < 1e-4)) {
50*57c64913Sjeremylt         printf("[%d] %f != %f=f(%f", dim, uq[i], fx, xx[0]);
51*57c64913Sjeremylt         for (CeedInt d=1; d<dim; d++) printf(",%f", xx[d]);
52*57c64913Sjeremylt         puts(")");
53*57c64913Sjeremylt       }
54*57c64913Sjeremylt     }
55*57c64913Sjeremylt 
56*57c64913Sjeremylt     CeedBasisDestroy(&bxl);
57*57c64913Sjeremylt     CeedBasisDestroy(&bul);
58*57c64913Sjeremylt     CeedBasisDestroy(&bxg);
59*57c64913Sjeremylt     CeedBasisDestroy(&bug);
60*57c64913Sjeremylt   }
61*57c64913Sjeremylt   CeedDestroy(&ceed);
62*57c64913Sjeremylt   return 0;
63*57c64913Sjeremylt }
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