xref: /libCEED/tests/t304-basis.c (revision 442e7f0bef50859918b48bfcea0f6ad2d729e89e)
1 /// @file
2 /// Test Symmetric Schur Decomposition
3 /// \test Test Symmetric Schur Decomposition
4 #include <ceed.h>
5 
6 int main(int argc, char **argv) {
7   Ceed ceed;
8   CeedScalar A[16] = {0.19996678, 0.0745459, -0.07448852, 0.0332866,
9                       0.0745459, 1., 0.16666509, -0.07448852,
10                       -0.07448852, 0.16666509, 1., 0.0745459,
11                       0.0332866, -0.07448852, 0.0745459, 0.19996678
12                      };
13   CeedScalar lambda[4];
14 
15   CeedInit(argv[1], &ceed);
16 
17   CeedSymmetricSchurDecomposition(ceed, A, lambda, 4);
18   fprintf(stdout, "Q:\n");
19   for (int i=0; i<4; i++) {
20     for (int j=0; j<4; j++) {
21       if (A[j+4*i] <= 1E-14 && A[j+4*i] >= -1E-14) A[j+4*i] = 0;
22       fprintf(stdout, "%12.8f\t", A[j+4*i]);
23     }
24     fprintf(stdout, "\n");
25   }
26   fprintf(stdout, "lambda:\n");
27   for (int i=0; i<4; i++) {
28     if (lambda[i] <= 1E-14 && lambda[i] >= -1E-14) lambda[i] = 0;
29     fprintf(stdout, "%12.8f\n", lambda[i]);
30   }
31   CeedDestroy(&ceed);
32   return 0;
33 }
34