xref: /libCEED/tests/t321-basis.c (revision d1d35e2f02dc969aee8debf3fd943dd784aa847a)

/// @file
/// Test interpolation with a 2D Simplex non-tensor H1 basis
/// \test Test interpolaton with a 2D Simplex non-tensor H1 basis
#include <ceed.h>
#include <math.h>
#include "t320-basis.h"

double feval(double x1, double x2) {
  return x1*x1 + x2*x2 + x1*x2 + 1;
}

int main(int argc, char **argv) {
  Ceed ceed;
  CeedVector In, Out;
  const CeedInt P = 6, Q = 4, dim = 2;
  CeedBasis b;
  CeedScalar q_ref[dim*Q], q_weight[Q];
  CeedScalar interp[P*Q], grad[dim*P*Q];
  CeedScalar xq[] = {0.2, 0.6, 1./3., 0.2, 0.2, 0.2, 1./3., 0.6};
  CeedScalar xr[] = {0., 0.5, 1., 0., 0.5, 0., 0., 0., 0., 0.5, 0.5, 1.};
  const CeedScalar *out;
  CeedScalar in[P], value;

  buildmats(q_ref, q_weight, interp, grad);

  CeedInit(argv[1], &ceed);

  CeedBasisCreateH1(ceed, CEED_TRIANGLE, 1, P, Q, interp, grad, q_ref,
                    q_weight, &b);

  // Interpolate function to quadrature points
  for (int i=0; i<P; i++)
    in[i] = feval(xr[0*P+i], xr[1*P+i]);

  CeedVectorCreate(ceed, P, &In);
  CeedVectorSetArray(In, CEED_MEM_HOST, CEED_USE_POINTER, in);
  CeedVectorCreate(ceed, Q, &Out);
  CeedVectorSetValue(Out, 0);

  CeedBasisApply(b, 1, CEED_NOTRANSPOSE, CEED_EVAL_INTERP, In, Out);

  // Check values at quadrature points
  CeedVectorGetArrayRead(Out, CEED_MEM_HOST, &out);
  for (int i=0; i<Q; i++) {
    value = feval(xq[0*Q+i], xq[1*Q+i]);
    if (fabs(out[i] - value) > 1E-10)
      // LCOV_EXCL_START
      printf("[%d] %f != %f\n", i, out[i], value);
    // LCOV_EXCL_STOP
  }
  CeedVectorRestoreArrayRead(Out, &out);

  CeedVectorDestroy(&In);
  CeedVectorDestroy(&Out);
  CeedBasisDestroy(&b);
  CeedDestroy(&ceed);
  return 0;
}