text: /// @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"
  
  CeedScalar feval(CeedScalar x1, CeedScalar 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_TOPOLOGY_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) > 100.*CEED_EPSILON)
        // 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;
  }
  