/* nag_dspsv (f07pac) Example Program. * * Copyright 2004 Numerical Algorithms Group. * * Mark 23, 2011. */ #include #include #include #include int main(void) { /* Scalars */ Integer exit_status = 0, i, j, n, nrhs, pdb; /* Arrays */ double *ap = 0, *b = 0; Integer *ipiv = 0; char nag_enum_arg[40]; /* Nag Types */ NagError fail; Nag_OrderType order; Nag_UploType uplo; #ifdef NAG_COLUMN_MAJOR #define A_UPPER(I, J) ap[J*(J-1)/2 + I - 1] #define A_LOWER(I, J) ap[(2*n-J)*(J-1)/2 + I - 1] #define B(I, J) b[(J-1)*pdb + I - 1] order = Nag_ColMajor; #else #define A_LOWER(I, J) ap[I*(I-1)/2 + J - 1] #define A_UPPER(I, J) ap[(2*n-I)*(I-1)/2 + J - 1] #define B(I, J) b[(I-1)*pdb + J - 1] order = Nag_RowMajor; #endif INIT_FAIL(fail); printf("nag_dspsv (f07pac) Example Program Results\n\n"); /* Skip heading in data file */ scanf("%*[^\n]"); scanf("%ld%ld%*[^\n]", &n, &nrhs); if (n < 0 || nrhs < 0) { printf("Invalid n or nrhs\n"); exit_status = 1; goto END; } scanf(" %s%*[^\n]", nag_enum_arg); /* nag_enum_name_to_value(x04nac). * Converts NAG enum member name to value */ uplo = (Nag_UploType) nag_enum_name_to_value(nag_enum_arg); /* Allocate memory */ if (!(ap = NAG_ALLOC(n*(n+1)/2, double)) || !(b = NAG_ALLOC(n*nrhs, double)) || !(ipiv = NAG_ALLOC(n, Integer))) { printf("Allocation failure\n"); exit_status = -1; goto END; } #ifdef NAG_COLUMN_MAJOR pdb = n; #else pdb = nrhs; #endif /* Read the triangular part of the matrix A from data file */ if (uplo == Nag_Upper) for (i = 1; i <= n; ++i) for (j = i; j <= n; ++j) scanf("%lf", &A_UPPER(i, j)); else for (i = 1; i <= n; ++i) for (j = 1; j <= i; ++j) scanf("%lf", &A_LOWER(i, j)); scanf("%*[^\n]"); /* Read b from data file */ for (i = 1; i <= n; ++i) for (j = 1; j <= nrhs; ++j) scanf("%lf", &B(i, j)); scanf("%*[^\n]"); /* Solve the equations Ax = b for x using nag_dspsv (f07pac). */ nag_dspsv(order, uplo, n, nrhs, ap, ipiv, b, pdb, &fail); if (fail.code != NE_NOERROR) { printf("Error from nag_dspsv (f07pac).\n%s\n", fail.message); exit_status = 1; goto END; } /* Print solution */ printf(" Solution\n"); for (i = 1; i <= n; ++i) { for (j = 1; j <= nrhs; ++j) printf(" %10.4f%s", B(i, j), j%7 == 0?"\n":""); printf("\n"); } END: if (ap) NAG_FREE(ap); if (b) NAG_FREE(b); if (ipiv) NAG_FREE(ipiv); return exit_status; } #undef A_UPPER #undef A_LOWER #undef B