text: /* 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"
  #include "blaswrap.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 */
      integer i__, j;
      doublereal eps;
      integer info;
      extern logical lsame_(char *, char *);
      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 */
  
  /*     .. Scalar Arguments .. */
  /*     .. */
  /*     .. Array Arguments .. */
  /*     .. */
  
  /*  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 ) */
  
  /*  ===================================================================== */
  
  /*     .. Parameters .. */
  /*     .. */
  /*     .. Local Scalars .. */
  /*     .. */
  /*     .. External Functions .. */
  /*     .. */
  /*     .. External Subroutines .. */
  /*     .. */
  /*     .. Intrinsic Functions .. */
  /*     .. */
  /*     .. Executable Statements .. */
  
  /*     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_ */
  