#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"

/* Subroutine */ int ctpt06_(real *rcond, real *rcondc, char *uplo, char *
	diag, integer *n, complex *ap, real *rwork, real *rat)
{
    /* System generated locals */
    real r__1, r__2;

    /* Local variables */
    static real rmin, rmax, anorm;
    extern doublereal slamch_(char *);
    static real bignum;
    extern doublereal clantp_(char *, char *, char *, integer *, complex *, 
	    real *);
    static real eps;


/*  -- LAPACK test routine (version 3.0) --   
       Univ. of Tennessee, Univ. of California Berkeley, NAG Ltd.,   
       Courant Institute, Argonne National Lab, and Rice University   
       February 29, 1992   


    Purpose   
    =======   

    CTPT06 computes a test ratio comparing RCOND (the reciprocal   
    condition number of the triangular matrix A) and RCONDC, the estimate   
    computed by CTPCON.  Information about the triangular matrix is used   
    if one estimate is zero and the other is non-zero to decide if   
    underflow in the estimate is justified.   

    Arguments   
    =========   

    RCOND   (input) REAL   
            The estimate of the reciprocal condition number obtained by   
            forming the explicit inverse of the matrix A and computing   
            RCOND = 1/( norm(A) * norm(inv(A)) ).   

    RCONDC  (input) REAL   
            The estimate of the reciprocal condition number computed by   
            CTPCON.   

    UPLO    (input) CHARACTER   
            Specifies whether the matrix A is upper or lower triangular.   
            = 'U':  Upper triangular   
            = 'L':  Lower triangular   

    DIAG    (input) CHARACTER   
            Specifies whether or not the matrix A is unit triangular.   
            = 'N':  Non-unit triangular   
            = 'U':  Unit triangular   

    N       (input) INTEGER   
            The order of the matrix A.  N >= 0.   

    AP      (input) COMPLEX array, dimension (N*(N+1)/2)   
            The upper or lower triangular matrix A, packed columnwise in   
            a linear array.  The j-th column of A is stored in the array   
            AP as follows:   
            if UPLO = 'U', AP((j-1)*j/2 + i) = A(i,j) for 1<=i<=j;   
            if UPLO = 'L',   
               AP((j-1)*(n-j) + j*(j+1)/2 + i-j) = A(i,j) for j<=i<=n.   

    RWORK   (workspace) REAL array, dimension (N)   

    RAT     (output) REAL   
            The test ratio.  If both RCOND and RCONDC are nonzero,   
               RAT = MAX( RCOND, RCONDC )/MIN( RCOND, RCONDC ) - 1.   
            If RAT = 0, the two estimates are exactly the same.   

    =====================================================================   


       Parameter adjustments */
    --rwork;
    --ap;

    /* Function Body */
    eps = slamch_("Epsilon");
    rmax = dmax(*rcond,*rcondc);
    rmin = dmin(*rcond,*rcondc);

/*     Do the easy cases first. */

    if (rmin < 0.f) {

/*        Invalid value for RCOND or RCONDC, return 1/EPS. */

	*rat = 1.f / eps;

    } else if (rmin > 0.f) {

/*        Both estimates are positive, return RMAX/RMIN - 1. */

	*rat = rmax / rmin - 1.f;

    } else if (rmax == 0.f) {

/*        Both estimates zero. */

	*rat = 0.f;

    } else {

/*        One estimate is zero, the other is non-zero.  If the matrix is   
          ill-conditioned, return the nonzero estimate multiplied by   
          1/EPS; if the matrix is badly scaled, return the nonzero   
          estimate multiplied by BIGNUM/TMAX, where TMAX is the maximum   
          element in absolute value in A. */

	bignum = 1.f / slamch_("Safe minimum");
	anorm = clantp_("M", uplo, diag, n, &ap[1], &rwork[1]);

/* Computing MIN */
	r__1 = bignum / dmax(1.f,anorm), r__2 = 1.f / eps;
	*rat = rmax * dmin(r__1,r__2);
    }

    return 0;

/*     End of CTPT06 */

} /* ctpt06_ */


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