#include "blaswrap.h" /* zsyt01.f -- translated by f2c (version 20061008). You must link the resulting object file with libf2c: on Microsoft Windows system, link with libf2c.lib; on Linux or Unix systems, link with .../path/to/libf2c.a -lm or, if you install libf2c.a in a standard place, with -lf2c -lm -- in that order, at the end of the command line, as in cc *.o -lf2c -lm Source for libf2c is in /netlib/f2c/libf2c.zip, e.g., http://www.netlib.org/f2c/libf2c.zip */ #include "f2c.h" /* Table of constant values */ static doublecomplex c_b1 = {0.,0.}; static doublecomplex c_b2 = {1.,0.}; /* Subroutine */ int zsyt01_(char *uplo, integer *n, doublecomplex *a, integer *lda, doublecomplex *afac, integer *ldafac, integer *ipiv, doublecomplex *c__, integer *ldc, doublereal *rwork, doublereal * 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; doublecomplex z__1; /* Local variables */ static integer i__, j; static doublereal eps; static integer info; extern logical lsame_(char *, char *); static doublereal anorm; extern doublereal dlamch_(char *); extern /* Subroutine */ int zlaset_(char *, integer *, integer *, doublecomplex *, doublecomplex *, doublecomplex *, integer *); extern doublereal zlansy_(char *, char *, integer *, doublecomplex *, integer *, doublereal *); extern /* Subroutine */ int zlavsy_(char *, char *, char *, integer *, integer *, doublecomplex *, integer *, integer *, doublecomplex *, integer *, integer *); /* -- LAPACK test routine (version 3.1) -- Univ. of Tennessee, Univ. of California Berkeley and NAG Ltd.. November 2006 Purpose ======= ZSYT01 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*16 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*16 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 ZSYTRF. LDAFAC (input) INTEGER The leading dimension of the array AFAC. LDAFAC >= max(1,N). IPIV (input) INTEGER array, dimension (N) The pivot indices from ZSYTRF. C (workspace) COMPLEX*16 array, dimension (LDC,N) LDC (integer) INTEGER The leading dimension of the array C. LDC >= max(1,N). RWORK (workspace) DOUBLE PRECISION array, dimension (N) RESID (output) DOUBLE PRECISION 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; a -= a_offset; afac_dim1 = *ldafac; afac_offset = 1 + afac_dim1; afac -= afac_offset; --ipiv; c_dim1 = *ldc; c_offset = 1 + c_dim1; c__ -= c_offset; --rwork; /* Function Body */ if (*n <= 0) { *resid = 0.; return 0; } /* Determine EPS and the norm of A. */ eps = dlamch_("Epsilon"); anorm = zlansy_("1", uplo, n, &a[a_offset], lda, &rwork[1]); /* Initialize C to the identity matrix. */ zlaset_("Full", n, n, &c_b1, &c_b2, &c__[c_offset], ldc); /* Call ZLAVSY to form the product D * U' (or D * L' ). */ zlavsy_(uplo, "Transpose", "Non-unit", n, n, &afac[afac_offset], ldafac, & ipiv[1], &c__[c_offset], ldc, &info); /* Call ZLAVSY again to multiply by U (or L ). */ zlavsy_(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 = i__ + j * c_dim1; i__4 = i__ + j * c_dim1; i__5 = i__ + j * a_dim1; z__1.r = c__[i__4].r - a[i__5].r, z__1.i = c__[i__4].i - a[ i__5].i; c__[i__3].r = z__1.r, c__[i__3].i = z__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 = i__ + j * c_dim1; i__4 = i__ + j * c_dim1; i__5 = i__ + j * a_dim1; z__1.r = c__[i__4].r - a[i__5].r, z__1.i = c__[i__4].i - a[ i__5].i; c__[i__3].r = z__1.r, c__[i__3].i = z__1.i; /* L30: */ } /* L40: */ } } /* Compute norm( C - A ) / ( N * norm(A) * EPS ) */ *resid = zlansy_("1", uplo, n, &c__[c_offset], ldc, &rwork[1]); if (anorm <= 0.) { if (*resid != 0.) { *resid = 1. / eps; } } else { *resid = *resid / (doublereal) (*n) / anorm / eps; } return 0; /* End of ZSYT01 */ } /* zsyt01_ */