xref: /libCEED/tests/t304-basis.c (revision 52bfb9bbf17f17edbcd45876cdc8689a879bc683)
14411cf47Sjeremylt /// @file
2*52bfb9bbSJeremy L Thompson /// Test Symmetric Schur Decomposition
3*52bfb9bbSJeremy L Thompson /// \test Test Symmetric Schur Decomposition
457c64913Sjeremylt #include <ceed.h>
557c64913Sjeremylt 
657c64913Sjeremylt int main(int argc, char **argv) {
757c64913Sjeremylt   Ceed ceed;
8*52bfb9bbSJeremy L Thompson   CeedScalar A[16] = {0.19996678, 0.0745459, -0.07448852, 0.0332866,
9*52bfb9bbSJeremy L Thompson                       0.0745459, 1., 0.16666509, -0.07448852,
10*52bfb9bbSJeremy L Thompson                       -0.07448852, 0.16666509, 1., 0.0745459,
11*52bfb9bbSJeremy L Thompson                       0.0332866, -0.07448852, 0.0745459, 0.19996678};
12*52bfb9bbSJeremy L Thompson   CeedScalar lambda[4];
1357c64913Sjeremylt 
1457c64913Sjeremylt   CeedInit(argv[1], &ceed);
15288c0443SJeremy L Thompson 
16*52bfb9bbSJeremy L Thompson   CeedSymmetricSchurDecomposition(ceed, A, lambda, 4);
17*52bfb9bbSJeremy L Thompson   fprintf(stdout, "Q:\n");
18*52bfb9bbSJeremy L Thompson   for (int i=0; i<4; i++) {
19*52bfb9bbSJeremy L Thompson     for (int j=0; j<4; j++) {
20*52bfb9bbSJeremy L Thompson       if (A[j+4*i] <= 1E-14 && A[j+4*i] >= -1E-14) A[j+4*i] = 0;
21*52bfb9bbSJeremy L Thompson       fprintf(stdout, "%12.8f\t", A[j+4*i]);
2257c64913Sjeremylt     }
23*52bfb9bbSJeremy L Thompson     fprintf(stdout, "\n");
24*52bfb9bbSJeremy L Thompson   }
25*52bfb9bbSJeremy L Thompson   fprintf(stdout, "lambda:\n");
26*52bfb9bbSJeremy L Thompson   for (int i=0; i<4; i++) {
27*52bfb9bbSJeremy L Thompson     if (lambda[i] <= 1E-14 && lambda[i] >= -1E-14) lambda[i] = 0;
28*52bfb9bbSJeremy L Thompson     fprintf(stdout, "%12.8f\n", lambda[i]);
2957c64913Sjeremylt   }
3057c64913Sjeremylt   CeedDestroy(&ceed);
3157c64913Sjeremylt   return 0;
3257c64913Sjeremylt }
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