xref: /libCEED/tests/t305-basis.c (revision 673160d747a9093c09c5196095b9e3a2083e30dd)
14411cf47Sjeremylt /// @file
252bfb9bbSJeremy L Thompson /// Test Simultaneous Diagonalization
352bfb9bbSJeremy L Thompson /// \test Simultaneous Diagonalization
457c64913Sjeremylt #include <ceed.h>
5*673160d7Sjeremylt #include <math.h>
657c64913Sjeremylt 
757c64913Sjeremylt int main(int argc, char **argv) {
857c64913Sjeremylt   Ceed ceed;
9*673160d7Sjeremylt   CeedInt P = 4, Q = 4;
10*673160d7Sjeremylt   CeedScalar M[P*P], K[P*P], X[P*P], lambda[P];
11*673160d7Sjeremylt   CeedBasis basis;
1257c64913Sjeremylt 
1357c64913Sjeremylt   CeedInit(argv[1], &ceed);
14aedaa0e5Sjeremylt 
15*673160d7Sjeremylt   // Create mass, stiffness matrix
16*673160d7Sjeremylt   CeedBasisCreateTensorH1Lagrange(ceed, 1, 1, P, Q, CEED_GAUSS, &basis);
17*673160d7Sjeremylt   const CeedScalar *interp, *grad, *quad_weights;
18*673160d7Sjeremylt   CeedBasisGetInterp(basis, &interp);
19*673160d7Sjeremylt   CeedBasisGetGrad(basis, &grad);
20*673160d7Sjeremylt   CeedBasisGetQWeights(basis, &quad_weights);
21*673160d7Sjeremylt   for (int i=0; i<P; i++)
22*673160d7Sjeremylt     for (int j=0; j<P; j++) {
23*673160d7Sjeremylt       CeedScalar sum_m = 0, sum_k = 0;
24*673160d7Sjeremylt       for (int k=0; k<Q; k++) {
25*673160d7Sjeremylt         sum_m += interp[P*k+i]*quad_weights[k]*interp[P*k+j];
26*673160d7Sjeremylt         sum_k += grad[P*k+i]*quad_weights[k]*grad[P*k+j];
27*673160d7Sjeremylt       }
28*673160d7Sjeremylt       M[P*i+j] = sum_m;
29*673160d7Sjeremylt       K[P*i+j] = sum_k;
30fb551037Sjeremylt     }
31fb551037Sjeremylt 
32*673160d7Sjeremylt   CeedSimultaneousDiagonalization(ceed, K, M, X, lambda, P);
33*673160d7Sjeremylt 
34*673160d7Sjeremylt   // Check X^T M X = I
35*673160d7Sjeremylt   CeedScalar work[P*P];
36*673160d7Sjeremylt   for (int i=0; i<P; i++)
37*673160d7Sjeremylt     for (int j=0; j<P; j++) {
38*673160d7Sjeremylt       CeedScalar sum = 0;
39*673160d7Sjeremylt       for (int k=0; k<P; k++)
40*673160d7Sjeremylt         sum += M[P*i+k]*X[P*k+j];
41*673160d7Sjeremylt       work[P*i+j] = sum;
4252bfb9bbSJeremy L Thompson     }
43*673160d7Sjeremylt   for (int i=0; i<P; i++)
44*673160d7Sjeremylt     for (int j=0; j<P; j++) {
45*673160d7Sjeremylt       CeedScalar sum = 0;
46*673160d7Sjeremylt       for (int k=0; k<P; k++)
47*673160d7Sjeremylt         sum += X[P*k+i]*work[P*k+j];
48*673160d7Sjeremylt       M[P*i+j] = sum;
4952bfb9bbSJeremy L Thompson     }
50*673160d7Sjeremylt   for (int i=0; i<P; i++)
51*673160d7Sjeremylt     for (int j=0; j<P; j++)
52*673160d7Sjeremylt       if (fabs(M[P*i+j] - (i == j ? 1.0 : 0.0)) > 1E-14)
53*673160d7Sjeremylt         // LCOV_EXCL_START
54*673160d7Sjeremylt         printf("Error in diagonalization of M [%d, %d]: %f != %f\n",
55*673160d7Sjeremylt                i, j, M[P*i+j], (i == j ? 1.0 : 0.0));
56*673160d7Sjeremylt   // LCOV_EXCL_STOP
57*673160d7Sjeremylt 
58*673160d7Sjeremylt   // Check X^T K X = Lamda
59*673160d7Sjeremylt   for (int i=0; i<P; i++)
60*673160d7Sjeremylt     for (int j=0; j<P; j++) {
61*673160d7Sjeremylt       CeedScalar sum = 0;
62*673160d7Sjeremylt       for (int k=0; k<P; k++)
63*673160d7Sjeremylt         sum += K[P*i+k]*X[P*k+j];
64*673160d7Sjeremylt       work[P*i+j] = sum;
6552bfb9bbSJeremy L Thompson     }
66*673160d7Sjeremylt   for (int i=0; i<P; i++)
67*673160d7Sjeremylt     for (int j=0; j<P; j++) {
68*673160d7Sjeremylt       CeedScalar sum = 0;
69*673160d7Sjeremylt       for (int k=0; k<P; k++)
70*673160d7Sjeremylt         sum += X[P*k+i]*work[P*k+j];
71*673160d7Sjeremylt       K[P*i+j] = sum;
72*673160d7Sjeremylt     }
73*673160d7Sjeremylt   for (int i=0; i<P; i++)
74*673160d7Sjeremylt     for (int j=0; j<P; j++)
75*673160d7Sjeremylt       if (fabs(K[P*i+j] - (i == j ? lambda[i] : 0.0)) > 1E-14)
76*673160d7Sjeremylt         // LCOV_EXCL_START
77*673160d7Sjeremylt         printf("Error in diagonalization of K [%d, %d]: %f != %f\n",
78*673160d7Sjeremylt                i, j, K[P*i+j], (i == j ? lambda[i] : 0.0));
79*673160d7Sjeremylt   // LCOV_EXCL_STOP
80*673160d7Sjeremylt 
81*673160d7Sjeremylt   CeedBasisDestroy(&basis);
8257c64913Sjeremylt   CeedDestroy(&ceed);
8357c64913Sjeremylt   return 0;
8457c64913Sjeremylt }
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