/* nag_zunghr (f08ntc) Example Program. * * Copyright 2001 Numerical Algorithms Group. * * Mark 7, 2001. */ #include #include #include #include #include int main(void) { /* Scalars */ Integer i, j, n, pda, pdz, tau_len, w_len; Integer exit_status=0; NagError fail; Nag_OrderType order; /* Arrays */ Complex *a=0, *tau=0, *w=0, *z=0; #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); Vprintf("nag_zunghr (f08ntc) Example Program Results\n\n"); /* Skip heading in data file */ Vscanf("%*[^\n] "); Vscanf("%ld%*[^\n] ", &n); #ifdef NAG_COLUMN_MAJOR pda = n; pdz = n; #else pda = n; pdz = n; #endif tau_len = n - 1; w_len = n; /* Allocate memory */ if ( !(a = NAG_ALLOC(n * n, Complex)) || !(tau = NAG_ALLOC(tau_len, Complex)) || !(w = NAG_ALLOC(w_len, Complex)) || !(z = NAG_ALLOC(n * n, Complex)) ) { Vprintf("Allocation failure\n"); exit_status = -1; goto END; } /* Read A from data file */ for (i = 1; i <= n; ++i) { for (j = 1; j <= n; ++j) Vscanf(" ( %lf , %lf )", &A(i,j).re, &A(i,j).im); } Vscanf("%*[^\n] "); /* Reduce A to upper Hessenberg form H = (Q**T)*A*Q */ /* nag_zgehrd (f08nsc). * Unitary reduction of complex general matrix to upper * Hessenberg form */ nag_zgehrd(order, n, 1, n, a, pda, tau, &fail); if (fail.code != NE_NOERROR) { Vprintf("Error from nag_zgehrd (f08nsc).\n%s\n", fail.message); exit_status = 1; goto END; } /* Copy A into Z */ for (i = 1; i <= n; ++i) { for (j = 1; j <= n; ++j) { Z(i,j).re = A(i,j).re; Z(i,j).im = A(i,j).im; } } /* Form Q explicitly, storing the result in Z */ /* nag_zunghr (f08ntc). * Generate unitary transformation matrix from reduction to * Hessenberg form determined by nag_zgehrd (f08nsc) */ nag_zunghr(order, n, 1, n, z, pdz, tau, &fail); if (fail.code != NE_NOERROR) { Vprintf("Error from nag_zunghr (f08ntc).\n%s\n", fail.message); exit_status = 1; goto END; } /* Calculate the Schur factorization of H = Y*T*(Y**T) and form */ /* Q*Y explicitly, storing the result in Z */ /* Note that A = Z*T*(Z**T), where Z = Q*Y */ /* nag_zhseqr (f08psc). * Eigenvalues and Schur factorization of complex upper * Hessenberg matrix reduced from complex general matrix */ nag_zhseqr(order, Nag_Schur, Nag_UpdateZ, n, 1, n, a, pda, w, z, pdz, &fail); if (fail.code != NE_NOERROR) { Vprintf("Error from nag_zhseqr (f08psc).\n%s\n", fail.message); exit_status = 1; goto END; } /* Print Schur form */ /* nag_gen_complx_mat_print_comp (x04dbc). * Print complex general matrix (comprehensive) */ nag_gen_complx_mat_print_comp(order, Nag_GeneralMatrix, Nag_NonUnitDiag, n, n, a, pda, Nag_BracketForm, "%7.4f", "Schur form", Nag_IntegerLabels, 0, Nag_IntegerLabels, 0, 80, 0, 0, &fail); if (fail.code != NE_NOERROR) { Vprintf("Error from nag_gen_complx_mat_print_comp (x04dbc).\n%s\n", fail.message); exit_status = 1; goto END; } /* Print Schur vectors */ Vprintf("\n"); /* nag_gen_complx_mat_print_comp (x04dbc), see above. */ nag_gen_complx_mat_print_comp(order, Nag_GeneralMatrix, Nag_NonUnitDiag, n, n, z, pdz, Nag_BracketForm, "%7.4f", "Schur vectors of A", Nag_IntegerLabels, 0, Nag_IntegerLabels, 0, 80, 0, 0, &fail); if (fail.code != NE_NOERROR) { Vprintf("Error from nag_gen_complx_mat_print_comp (x04dbc).\n%s\n", fail.message); exit_status = 1; goto END; } END: if (a) NAG_FREE(a); if (tau) NAG_FREE(tau); if (w) NAG_FREE(w); if (z) NAG_FREE(z); return exit_status; }