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 #include <stdio.h> 8 9 int main(int argc, char **argv) { 10 Ceed ceed; 11 CeedInt p = 4; 12 CeedScalar M[16], Q[16], lambda[4], Q_lambda_Qt[16]; 13 CeedBasis basis; 14 const CeedScalar *interpolation, *quadrature_weights; 15 16 CeedInit(argv[1], &ceed); 17 18 // Create mass matrix 19 CeedBasisCreateTensorH1Lagrange(ceed, 1, 1, p, p, CEED_GAUSS, &basis); 20 CeedBasisGetInterp(basis, &interpolation); 21 CeedBasisGetQWeights(basis, &quadrature_weights); 22 for (int i = 0; i < p; i++) { 23 for (int j = 0; j < p; j++) { 24 CeedScalar sum = 0; 25 for (int k = 0; k < p; k++) sum += interpolation[p * k + i] * quadrature_weights[k] * interpolation[p * k + j]; 26 M[p * i + j] = sum; 27 Q[p * i + j] = sum; 28 } 29 } 30 31 CeedSymmetricSchurDecomposition(ceed, Q, lambda, p); 32 33 // Check diagonalization of M 34 for (int i = 0; i < p; i++) { 35 for (int j = 0; j < p; j++) { 36 CeedScalar sum = 0; 37 for (int k = 0; k < p; k++) sum += Q[p * i + k] * lambda[k] * Q[p * j + k]; 38 Q_lambda_Qt[p * i + j] = sum; 39 } 40 } 41 for (int i = 0; i < p; i++) { 42 for (int j = 0; j < p; j++) { 43 if (fabs(M[p * i + j] - Q_lambda_Qt[p * i + j]) > 100. * CEED_EPSILON) { 44 // LCOV_EXCL_START 45 printf("Error in diagonalization [%" CeedInt_FMT ", %" CeedInt_FMT "]: %f != %f\n", i, j, M[p * i + j], Q_lambda_Qt[p * i + j]); 46 // LCOV_EXCL_STOP 47 } 48 } 49 } 50 51 CeedBasisDestroy(&basis); 52 CeedDestroy(&ceed); 53 return 0; 54 } 55