1 /// @file 2 /// Test Symmetric Schur Decomposition 3 /// \test Test Symmetric Schur Decomposition 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 M[16], Q[16], lambda[4], Q_lambda_Qt[16]; 12 CeedBasis basis; 13 const CeedScalar *interpolation, *quadrature_weights; 14 15 CeedInit(argv[1], &ceed); 16 17 // Create mass matrix 18 CeedBasisCreateTensorH1Lagrange(ceed, 1, 1, p, p, CEED_GAUSS, &basis); 19 CeedBasisGetInterp(basis, &interpolation); 20 CeedBasisGetQWeights(basis, &quadrature_weights); 21 for (int i = 0; i < p; i++) { 22 for (int j = 0; j < p; j++) { 23 CeedScalar sum = 0; 24 for (int k = 0; k < p; k++) sum += interpolation[p * k + i] * quadrature_weights[k] * interpolation[p * k + j]; 25 M[p * i + j] = sum; 26 Q[p * i + j] = sum; 27 } 28 } 29 30 CeedSymmetricSchurDecomposition(ceed, Q, lambda, p); 31 32 // Check diagonalization of M 33 for (int i = 0; i < p; i++) { 34 for (int j = 0; j < p; j++) { 35 CeedScalar sum = 0; 36 for (int k = 0; k < p; k++) sum += Q[p * i + k] * lambda[k] * Q[p * j + k]; 37 Q_lambda_Qt[p * i + j] = sum; 38 } 39 } 40 for (int i = 0; i < p; i++) { 41 for (int j = 0; j < p; j++) { 42 if (fabs(M[p * i + j] - Q_lambda_Qt[p * i + j]) > 100. * CEED_EPSILON) { 43 // LCOV_EXCL_START 44 printf("Error in diagonalization [%" CeedInt_FMT ", %" CeedInt_FMT "]: %f != %f\n", i, j, M[p * i + j], Q_lambda_Qt[p * i + j]); 45 // LCOV_EXCL_STOP 46 } 47 } 48 } 49 50 CeedBasisDestroy(&basis); 51 CeedDestroy(&ceed); 52 return 0; 53 } 54