#include "blaswrap.h" /* -- translated by f2c (version 19990503). You must link the resulting object file with the libraries: -lf2c -lm (in that order) */ #include "f2c.h" /* Table of constant values */ static complex c_b1 = {0.f,0.f}; static complex c_b2 = {1.f,0.f}; /* Subroutine */ int csyt01_(char *uplo, integer *n, complex *a, integer *lda, complex *afac, integer *ldafac, integer *ipiv, complex *c__, integer *ldc, real *rwork, real *resid) { /* System generated locals */ integer a_dim1, a_offset, afac_dim1, afac_offset, c_dim1, c_offset, i__1, i__2, i__3, i__4, i__5; complex q__1; /* Local variables */ static integer info, i__, j; extern logical lsame_(char *, char *); static real anorm; extern doublereal slamch_(char *); extern /* Subroutine */ int claset_(char *, integer *, integer *, complex *, complex *, complex *, integer *); extern doublereal clansy_(char *, char *, integer *, complex *, integer *, real *); extern /* Subroutine */ int clavsy_(char *, char *, char *, integer *, integer *, complex *, integer *, integer *, complex *, integer *, integer *); static real eps; #define a_subscr(a_1,a_2) (a_2)*a_dim1 + a_1 #define a_ref(a_1,a_2) a[a_subscr(a_1,a_2)] #define c___subscr(a_1,a_2) (a_2)*c_dim1 + a_1 #define c___ref(a_1,a_2) c__[c___subscr(a_1,a_2)] /* -- LAPACK test routine (version 3.0) -- Univ. of Tennessee, Univ. of California Berkeley, NAG Ltd., Courant Institute, Argonne National Lab, and Rice University September 30, 1994 Purpose ======= CSYT01 reconstructs a complex symmetric indefinite matrix A from its block L*D*L' or U*D*U' factorization and computes the residual norm( C - A ) / ( N * norm(A) * EPS ), where C is the reconstructed matrix, EPS is the machine epsilon, L' is the transpose of L, and U' is the transpose of U. Arguments ========== UPLO (input) CHARACTER*1 Specifies whether the upper or lower triangular part of the complex symmetric matrix A is stored: = 'U': Upper triangular = 'L': Lower triangular N (input) INTEGER The number of rows and columns of the matrix A. N >= 0. A (input) COMPLEX array, dimension (LDA,N) The original complex symmetric matrix A. LDA (input) INTEGER The leading dimension of the array A. LDA >= max(1,N) AFAC (input) COMPLEX array, dimension (LDAFAC,N) The factored form of the matrix A. AFAC contains the block diagonal matrix D and the multipliers used to obtain the factor L or U from the block L*D*L' or U*D*U' factorization as computed by CSYTRF. LDAFAC (input) INTEGER The leading dimension of the array AFAC. LDAFAC >= max(1,N). IPIV (input) INTEGER array, dimension (N) The pivot indices from CSYTRF. C (workspace) COMPLEX array, dimension (LDC,N) LDC (integer) INTEGER The leading dimension of the array C. LDC >= max(1,N). RWORK (workspace) REAL array, dimension (N) RESID (output) REAL If UPLO = 'L', norm(L*D*L' - A) / ( N * norm(A) * EPS ) If UPLO = 'U', norm(U*D*U' - A) / ( N * norm(A) * EPS ) ===================================================================== Quick exit if N = 0. Parameter adjustments */ a_dim1 = *lda; a_offset = 1 + a_dim1 * 1; a -= a_offset; afac_dim1 = *ldafac; afac_offset = 1 + afac_dim1 * 1; afac -= afac_offset; --ipiv; c_dim1 = *ldc; c_offset = 1 + c_dim1 * 1; c__ -= c_offset; --rwork; /* Function Body */ if (*n <= 0) { *resid = 0.f; return 0; } /* Determine EPS and the norm of A. */ eps = slamch_("Epsilon"); anorm = clansy_("1", uplo, n, &a[a_offset], lda, &rwork[1]); /* Initialize C to the identity matrix. */ claset_("Full", n, n, &c_b1, &c_b2, &c__[c_offset], ldc); /* Call CLAVSY to form the product D * U' (or D * L' ). */ clavsy_(uplo, "Transpose", "Non-unit", n, n, &afac[afac_offset], ldafac, & ipiv[1], &c__[c_offset], ldc, &info); /* Call CLAVSY again to multiply by U (or L ). */ clavsy_(uplo, "No transpose", "Unit", n, n, &afac[afac_offset], ldafac, & ipiv[1], &c__[c_offset], ldc, &info); /* Compute the difference C - A . */ if (lsame_(uplo, "U")) { i__1 = *n; for (j = 1; j <= i__1; ++j) { i__2 = j; for (i__ = 1; i__ <= i__2; ++i__) { i__3 = c___subscr(i__, j); i__4 = c___subscr(i__, j); i__5 = a_subscr(i__, j); q__1.r = c__[i__4].r - a[i__5].r, q__1.i = c__[i__4].i - a[ i__5].i; c__[i__3].r = q__1.r, c__[i__3].i = q__1.i; /* L10: */ } /* L20: */ } } else { i__1 = *n; for (j = 1; j <= i__1; ++j) { i__2 = *n; for (i__ = j; i__ <= i__2; ++i__) { i__3 = c___subscr(i__, j); i__4 = c___subscr(i__, j); i__5 = a_subscr(i__, j); q__1.r = c__[i__4].r - a[i__5].r, q__1.i = c__[i__4].i - a[ i__5].i; c__[i__3].r = q__1.r, c__[i__3].i = q__1.i; /* L30: */ } /* L40: */ } } /* Compute norm( C - A ) / ( N * norm(A) * EPS ) */ *resid = clansy_("1", uplo, n, &c__[c_offset], ldc, &rwork[1]); if (anorm <= 0.f) { if (*resid != 0.f) { *resid = 1.f / eps; } } else { *resid = *resid / (real) (*n) / anorm / eps; } return 0; /* End of CSYT01 */ } /* csyt01_ */ #undef c___ref #undef c___subscr #undef a_ref #undef a_subscr .