/* nag_dtrsyl (f08qhc) Example Program. * * Copyright 2001 Numerical Algorithms Group. * * Mark 7, 2001. */ #include #include #include #include #include int main(void) { /* Scalars */ Integer i, j, m, n, pda, pdb, pdc; Integer exit_status=0; double scale; NagError fail; Nag_OrderType order; /* Arrays */ double *a=0, *b=0, *c=0; #ifdef NAG_COLUMN_MAJOR #define A(I,J) a[(J-1)*pda + I - 1] #define B(I,J) b[(J-1)*pdb + I - 1] #define C(I,J) c[(J-1)*pdc + I - 1] order = Nag_ColMajor; #else #define A(I,J) a[(I-1)*pda + J - 1] #define B(I,J) b[(I-1)*pdb + J - 1] #define C(I,J) c[(I-1)*pdc + J - 1] order = Nag_RowMajor; #endif INIT_FAIL(fail); Vprintf("nag_dtrsyl (f08qhc) Example Program Results\n\n"); /* Skip heading in data file */ Vscanf("%*[^\n] "); Vscanf("%ld%ld%*[^\n] ", &m, &n); #ifdef NAG_COLUMN_MAJOR pda = m; pdb = n; pdc = m; #else pda = m; pdb = n; pdc = n; #endif /* Allocate memory */ if ( !(a = NAG_ALLOC(m * m, double)) || !(b = NAG_ALLOC(n * m, double)) || !(c = NAG_ALLOC(m * n, double)) ) { Vprintf("Allocation failure\n"); exit_status = -1; goto END; } /* Read A, B and C from data file */ for (i = 1; i <= m; ++i) { for (j = 1; j <= m; ++j) Vscanf("%lf", &A(i,j)); } Vscanf("%*[^\n] "); for (i = 1; i <= n; ++i) { for (j = 1; j <= n; ++j) Vscanf("%lf", &B(i,j)); } Vscanf("%*[^\n] "); for (i = 1; i <= m; ++i) { for (j = 1; j <= n; ++j) Vscanf("%lf", &C(i,j)); } Vscanf("%*[^\n] "); /* Reorder the Schur factorization T */ /* nag_dtrsyl (f08qhc). * Solve real Sylvester matrix equation AX~+~XB~=~C, A and B * are upper quasi-triangular or transposes */ nag_dtrsyl(order, Nag_NoTrans, Nag_NoTrans, Nag_Plus, m, n, a, pda, b, pdb, c, pdc, &scale, &fail); if (fail.code != NE_NOERROR) { Vprintf("Error from nag_dtrsyl (f08qhc).\n%s\n", fail.message); exit_status = 1; goto END; } /* Print the solution matrix X stored in C */ /* nag_gen_real_mat_print (x04cac). * Print real general matrix (easy-to-use) */ nag_gen_real_mat_print(order, Nag_GeneralMatrix, Nag_NonUnitDiag, m, n, c, pdc, "Solution matrix X", 0, &fail); if (fail.code != NE_NOERROR) { Vprintf("Error from nag_gen_real_mat_print (x04cac).\n%s\n", fail.message); exit_status = 1; goto END; } Vprintf("\n SCALE = %10.2e\n", scale); END: if (a) NAG_FREE(a); if (b) NAG_FREE(b); if (c) NAG_FREE(c); return exit_status; }