/// @file
/// Test QR Factorization
/// \test Test QR Factorization
#include <ceed.h>
#include <ceed/backend.h>
#include <math.h>

int main(int argc, char **argv) {
  Ceed ceed;
  CeedScalar A[12]    = {1, -1, 4, 1, 4, -2, 1, 4, 2, 1, -1, 0};
  CeedScalar qr[12]   = {1, -1, 4, 1, 4, -2, 1, 4, 2, 1, -1, 0};
  CeedScalar A_qr[12] = {0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0};
  CeedScalar tau[4];

  CeedInit(argv[1], &ceed);

  CeedQRFactorization(ceed, qr, tau, 4, 3);
  for (CeedInt i=0; i<3; i++)
    for (CeedInt j=i; j<3; j++)
      A_qr[i*3+j] = qr[i*3+j];
  CeedHouseholderApplyQ(A_qr, qr, tau, CEED_NOTRANSPOSE, 4, 3, 3, 3, 1);

  for (CeedInt i=0; i<12; i++)
    if (fabs(A_qr[i] - A[i]) > 100.*CEED_EPSILON)
      // LCOV_EXCL_START
      printf("Error in QR factorization A_qr[%" CeedInt_FMT
             "] = %f != A[%" CeedInt_FMT "] = %f\n", i, A_qr[i], i, A[i]);
  // LCOV_EXCL_STOP

  CeedDestroy(&ceed);
  return 0;
}