/* nag_zheevr (f08frc) Example Program. * * Copyright 2011 Numerical Algorithms Group. * * Mark 23, 2011. */ #include #include #include #include #include #include int main(void) { /* Scalars */ double abstol, vl = 0.0, vu = 0.0; Integer i, il, iu, j, m, n, pda, pdz; Integer exit_status = 0; /* Arrays */ Complex *a = 0, *z = 0; double *w = 0; Integer *isuppz = 0; /* Nag Types */ Nag_OrderType order; NagError fail; #ifdef NAG_COLUMN_MAJOR #define A(I, J) a[(J - 1) * pda + I - 1] #define Z(I, J) z[(J - 1) * pdz + I - 1] order = Nag_ColMajor; #else #define A(I, J) a[(I - 1) * pda + J - 1] #define Z(I, J) z[(I - 1) * pdz + J - 1] order = Nag_RowMajor; #endif INIT_FAIL(fail); printf("nag_zheevr (f08frc) Example Program Results\n\n"); /* Skip heading in data file and read n and the lower and upper * indices of the smallest and largest eigenvalues to be found. */ scanf("%*[^\n]"); scanf("%ld%ld%ld%*[^\n]", &n, &il, &iu); m = iu - il + 1; pda = n; pdz = n; /* Allocate memory */ if (!(a = NAG_ALLOC(n*n, Complex)) || !(z = NAG_ALLOC(n*pdz, Complex)) || !(w = NAG_ALLOC(n, double)) || !(isuppz = NAG_ALLOC(2*pdz, Integer))) { printf("Allocation failure\n"); exit_status = -1; goto END; } /* Read the upper triangular part of the matrix A from data file */ for (i = 1; i <= n; ++i) for (j = i; j <= n; ++j) scanf(" ( %lf , %lf )", &A(i, j).re, &A(i, j).im); scanf("%*[^\n]"); /* Set the absolute error tolerance for eigenvalues. * With abstol set to zero, the default value is used instead. */ abstol = 0.0; /* nag_zheevr (f08frc). * Solve the symmetric eigenvalue problem. */ nag_zheevr(order, Nag_DoBoth, Nag_Indices, Nag_Upper, n, a, pda, vl, vu, il, iu, abstol, &m, w, z, pdz, isuppz, &fail); if (fail.code != NE_NOERROR) { printf("Error from nag_zheevr (f08frc).\n%s\n", fail.message); exit_status = 1; goto END; } /* nag_complex_divide (a02cdc). * Normalize the eigenvectors. */ for(j=1; j<=m; j++) for(i=n; i>=1; i--) Z(i, j) = nag_complex_divide(Z(i, j),Z(1, j)); /* Print solution */ printf("Selected eigenvalues\n"); for (j = 0; j < m; ++j) printf("%8.4f%s", w[j], (j+1)%8 == 0?"\n":" "); printf("\n"); /* nag_gen_complx_mat_print (x04dac). * Print selected eigenvectors. */ fflush(stdout); nag_gen_complx_mat_print(order, Nag_GeneralMatrix, Nag_NonUnitDiag, n, m, z, pdz, "Selected eigenvectors", 0, &fail); if (fail.code != NE_NOERROR) { printf("Error from nag_gen_complx_mat_print (x04dac).\n%s\n", fail.message); exit_status = 1; goto END; } END: NAG_FREE(a); NAG_FREE(z); NAG_FREE(w); NAG_FREE(isuppz); return exit_status; } #undef A #undef Z