#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 doublereal c_b11 = -1.;
static doublereal c_b12 = 0.;

/* Subroutine */ int dpot03_(char *uplo, integer *n, doublereal *a, integer *
	lda, doublereal *ainv, integer *ldainv, doublereal *work, integer *
	ldwork, doublereal *rwork, doublereal *rcond, doublereal *resid)
{
    /* System generated locals */
    integer a_dim1, a_offset, ainv_dim1, ainv_offset, work_dim1, work_offset, 
	    i__1, i__2;

    /* Local variables */
    static integer i__, j;
    extern logical lsame_(char *, char *);
    static doublereal anorm;
    extern /* Subroutine */ int dsymm_(char *, char *, integer *, integer *, 
	    doublereal *, doublereal *, integer *, doublereal *, integer *, 
	    doublereal *, doublereal *, integer *);
    extern doublereal dlamch_(char *), dlange_(char *, integer *, 
	    integer *, doublereal *, integer *, doublereal *);
    static doublereal ainvnm;
    extern doublereal dlansy_(char *, char *, integer *, doublereal *, 
	    integer *, doublereal *);
    static doublereal eps;


#define ainv_ref(a_1,a_2) ainv[(a_2)*ainv_dim1 + a_1]
#define work_ref(a_1,a_2) work[(a_2)*work_dim1 + a_1]


/*  -- 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   
    =======   

    DPOT03 computes the residual for a symmetric matrix times its   
    inverse:   
       norm( I - A*AINV ) / ( N * norm(A) * norm(AINV) * EPS ),   
    where EPS is the machine epsilon.   

    Arguments   
    ==========   

    UPLO    (input) CHARACTER*1   
            Specifies whether the upper or lower triangular part of the   
            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) DOUBLE PRECISION array, dimension (LDA,N)   
            The original symmetric matrix A.   

    LDA     (input) INTEGER   
            The leading dimension of the array A.  LDA >= max(1,N)   

    AINV    (input/output) DOUBLE PRECISION array, dimension (LDAINV,N)   
            On entry, the inverse of the matrix A, stored as a symmetric   
            matrix in the same format as A.   
            In this version, AINV is expanded into a full matrix and   
            multiplied by A, so the opposing triangle of AINV will be   
            changed; i.e., if the upper triangular part of AINV is   
            stored, the lower triangular part will be used as work space.   

    LDAINV  (input) INTEGER   
            The leading dimension of the array AINV.  LDAINV >= max(1,N).   

    WORK    (workspace) DOUBLE PRECISION array, dimension (LDWORK,N)   

    LDWORK  (input) INTEGER   
            The leading dimension of the array WORK.  LDWORK >= max(1,N).   

    RWORK   (workspace) DOUBLE PRECISION array, dimension (N)   

    RCOND   (output) DOUBLE PRECISION   
            The reciprocal of the condition number of A, computed as   
            ( 1/norm(A) ) / norm(AINV).   

    RESID   (output) DOUBLE PRECISION   
            norm(I - A*AINV) / ( N * norm(A) * norm(AINV) * EPS )   

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


       Quick exit if N = 0.   

       Parameter adjustments */
    a_dim1 = *lda;
    a_offset = 1 + a_dim1 * 1;
    a -= a_offset;
    ainv_dim1 = *ldainv;
    ainv_offset = 1 + ainv_dim1 * 1;
    ainv -= ainv_offset;
    work_dim1 = *ldwork;
    work_offset = 1 + work_dim1 * 1;
    work -= work_offset;
    --rwork;

    /* Function Body */
    if (*n <= 0) {
	*rcond = 1.;
	*resid = 0.;
	return 0;
    }

/*     Exit with RESID = 1/EPS if ANORM = 0 or AINVNM = 0. */

    eps = dlamch_("Epsilon");
    anorm = dlansy_("1", uplo, n, &a[a_offset], lda, &rwork[1]);
    ainvnm = dlansy_("1", uplo, n, &ainv[ainv_offset], ldainv, &rwork[1]);
    if (anorm <= 0. || ainvnm <= 0.) {
	*rcond = 0.;
	*resid = 1. / eps;
	return 0;
    }
    *rcond = 1. / anorm / ainvnm;

/*     Expand AINV into a full matrix and call DSYMM to multiply   
       AINV on the left by A. */

    if (lsame_(uplo, "U")) {
	i__1 = *n;
	for (j = 1; j <= i__1; ++j) {
	    i__2 = j - 1;
	    for (i__ = 1; i__ <= i__2; ++i__) {
		ainv_ref(j, i__) = ainv_ref(i__, j);
/* L10: */
	    }
/* L20: */
	}
    } else {
	i__1 = *n;
	for (j = 1; j <= i__1; ++j) {
	    i__2 = *n;
	    for (i__ = j + 1; i__ <= i__2; ++i__) {
		ainv_ref(j, i__) = ainv_ref(i__, j);
/* L30: */
	    }
/* L40: */
	}
    }
    dsymm_("Left", uplo, n, n, &c_b11, &a[a_offset], lda, &ainv[ainv_offset], 
	    ldainv, &c_b12, &work[work_offset], ldwork);

/*     Add the identity matrix to WORK . */

    i__1 = *n;
    for (i__ = 1; i__ <= i__1; ++i__) {
	work_ref(i__, i__) = work_ref(i__, i__) + 1.;
/* L50: */
    }

/*     Compute norm(I - A*AINV) / (N * norm(A) * norm(AINV) * EPS) */

    *resid = dlange_("1", n, n, &work[work_offset], ldwork, &rwork[1]);

    *resid = *resid * *rcond / eps / (doublereal) (*n);

    return 0;

/*     End of DPOT03 */

} /* dpot03_ */

#undef work_ref
#undef ainv_ref


