#include "blaswrap.h"
/* sbdt01.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 integer c__1 = 1;
static real c_b7 = -1.f;
static real c_b9 = 1.f;

/* Subroutine */ int sbdt01_(integer *m, integer *n, integer *kd, real *a, 
	integer *lda, real *q, integer *ldq, real *d__, real *e, real *pt, 
	integer *ldpt, real *work, real *resid)
{
    /* System generated locals */
    integer a_dim1, a_offset, pt_dim1, pt_offset, q_dim1, q_offset, i__1, 
	    i__2;
    real r__1, r__2;

    /* Local variables */
    static integer i__, j;
    static real eps, anorm;
    extern /* Subroutine */ int sgemv_(char *, integer *, integer *, real *, 
	    real *, integer *, real *, integer *, real *, real *, integer *);
    extern doublereal sasum_(integer *, real *, integer *);
    extern /* Subroutine */ int scopy_(integer *, real *, integer *, real *, 
	    integer *);
    extern doublereal slamch_(char *), slange_(char *, integer *, 
	    integer *, real *, integer *, real *);


/*  -- LAPACK test routine (version 3.1) --   
       Univ. of Tennessee, Univ. of California Berkeley and NAG Ltd..   
       November 2006   


    Purpose   
    =======   

    SBDT01 reconstructs a general matrix A from its bidiagonal form   
       A = Q * B * P'   
    where Q (m by min(m,n)) and P' (min(m,n) by n) are orthogonal   
    matrices and B is bidiagonal.   

    The test ratio to test the reduction is   
       RESID = norm( A - Q * B * PT ) / ( n * norm(A) * EPS )   
    where PT = P' and EPS is the machine precision.   

    Arguments   
    =========   

    M       (input) INTEGER   
            The number of rows of the matrices A and Q.   

    N       (input) INTEGER   
            The number of columns of the matrices A and P'.   

    KD      (input) INTEGER   
            If KD = 0, B is diagonal and the array E is not referenced.   
            If KD = 1, the reduction was performed by xGEBRD; B is upper   
            bidiagonal if M >= N, and lower bidiagonal if M < N.   
            If KD = -1, the reduction was performed by xGBBRD; B is   
            always upper bidiagonal.   

    A       (input) REAL array, dimension (LDA,N)   
            The m by n matrix A.   

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

    Q       (input) REAL array, dimension (LDQ,N)   
            The m by min(m,n) orthogonal matrix Q in the reduction   
            A = Q * B * P'.   

    LDQ     (input) INTEGER   
            The leading dimension of the array Q.  LDQ >= max(1,M).   

    D       (input) REAL array, dimension (min(M,N))   
            The diagonal elements of the bidiagonal matrix B.   

    E       (input) REAL array, dimension (min(M,N)-1)   
            The superdiagonal elements of the bidiagonal matrix B if   
            m >= n, or the subdiagonal elements of B if m < n.   

    PT      (input) REAL array, dimension (LDPT,N)   
            The min(m,n) by n orthogonal matrix P' in the reduction   
            A = Q * B * P'.   

    LDPT    (input) INTEGER   
            The leading dimension of the array PT.   
            LDPT >= max(1,min(M,N)).   

    WORK    (workspace) REAL array, dimension (M+N)   

    RESID   (output) REAL   
            The test ratio:  norm(A - Q * B * P') / ( n * norm(A) * EPS )   

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


       Quick return if possible   

       Parameter adjustments */
    a_dim1 = *lda;
    a_offset = 1 + a_dim1;
    a -= a_offset;
    q_dim1 = *ldq;
    q_offset = 1 + q_dim1;
    q -= q_offset;
    --d__;
    --e;
    pt_dim1 = *ldpt;
    pt_offset = 1 + pt_dim1;
    pt -= pt_offset;
    --work;

    /* Function Body */
    if (*m <= 0 || *n <= 0) {
	*resid = 0.f;
	return 0;
    }

/*     Compute A - Q * B * P' one column at a time. */

    *resid = 0.f;
    if (*kd != 0) {

/*        B is bidiagonal. */

	if (*kd != 0 && *m >= *n) {

/*           B is upper bidiagonal and M >= N. */

	    i__1 = *n;
	    for (j = 1; j <= i__1; ++j) {
		scopy_(m, &a[j * a_dim1 + 1], &c__1, &work[1], &c__1);
		i__2 = *n - 1;
		for (i__ = 1; i__ <= i__2; ++i__) {
		    work[*m + i__] = d__[i__] * pt[i__ + j * pt_dim1] + e[i__]
			     * pt[i__ + 1 + j * pt_dim1];
/* L10: */
		}
		work[*m + *n] = d__[*n] * pt[*n + j * pt_dim1];
		sgemv_("No transpose", m, n, &c_b7, &q[q_offset], ldq, &work[*
			m + 1], &c__1, &c_b9, &work[1], &c__1);
/* Computing MAX */
		r__1 = *resid, r__2 = sasum_(m, &work[1], &c__1);
		*resid = dmax(r__1,r__2);
/* L20: */
	    }
	} else if (*kd < 0) {

/*           B is upper bidiagonal and M < N. */

	    i__1 = *n;
	    for (j = 1; j <= i__1; ++j) {
		scopy_(m, &a[j * a_dim1 + 1], &c__1, &work[1], &c__1);
		i__2 = *m - 1;
		for (i__ = 1; i__ <= i__2; ++i__) {
		    work[*m + i__] = d__[i__] * pt[i__ + j * pt_dim1] + e[i__]
			     * pt[i__ + 1 + j * pt_dim1];
/* L30: */
		}
		work[*m + *m] = d__[*m] * pt[*m + j * pt_dim1];
		sgemv_("No transpose", m, m, &c_b7, &q[q_offset], ldq, &work[*
			m + 1], &c__1, &c_b9, &work[1], &c__1);
/* Computing MAX */
		r__1 = *resid, r__2 = sasum_(m, &work[1], &c__1);
		*resid = dmax(r__1,r__2);
/* L40: */
	    }
	} else {

/*           B is lower bidiagonal. */

	    i__1 = *n;
	    for (j = 1; j <= i__1; ++j) {
		scopy_(m, &a[j * a_dim1 + 1], &c__1, &work[1], &c__1);
		work[*m + 1] = d__[1] * pt[j * pt_dim1 + 1];
		i__2 = *m;
		for (i__ = 2; i__ <= i__2; ++i__) {
		    work[*m + i__] = e[i__ - 1] * pt[i__ - 1 + j * pt_dim1] + 
			    d__[i__] * pt[i__ + j * pt_dim1];
/* L50: */
		}
		sgemv_("No transpose", m, m, &c_b7, &q[q_offset], ldq, &work[*
			m + 1], &c__1, &c_b9, &work[1], &c__1);
/* Computing MAX */
		r__1 = *resid, r__2 = sasum_(m, &work[1], &c__1);
		*resid = dmax(r__1,r__2);
/* L60: */
	    }
	}
    } else {

/*        B is diagonal. */

	if (*m >= *n) {
	    i__1 = *n;
	    for (j = 1; j <= i__1; ++j) {
		scopy_(m, &a[j * a_dim1 + 1], &c__1, &work[1], &c__1);
		i__2 = *n;
		for (i__ = 1; i__ <= i__2; ++i__) {
		    work[*m + i__] = d__[i__] * pt[i__ + j * pt_dim1];
/* L70: */
		}
		sgemv_("No transpose", m, n, &c_b7, &q[q_offset], ldq, &work[*
			m + 1], &c__1, &c_b9, &work[1], &c__1);
/* Computing MAX */
		r__1 = *resid, r__2 = sasum_(m, &work[1], &c__1);
		*resid = dmax(r__1,r__2);
/* L80: */
	    }
	} else {
	    i__1 = *n;
	    for (j = 1; j <= i__1; ++j) {
		scopy_(m, &a[j * a_dim1 + 1], &c__1, &work[1], &c__1);
		i__2 = *m;
		for (i__ = 1; i__ <= i__2; ++i__) {
		    work[*m + i__] = d__[i__] * pt[i__ + j * pt_dim1];
/* L90: */
		}
		sgemv_("No transpose", m, m, &c_b7, &q[q_offset], ldq, &work[*
			m + 1], &c__1, &c_b9, &work[1], &c__1);
/* Computing MAX */
		r__1 = *resid, r__2 = sasum_(m, &work[1], &c__1);
		*resid = dmax(r__1,r__2);
/* L100: */
	    }
	}
    }

/*     Compute norm(A - Q * B * P') / ( n * norm(A) * EPS ) */

    anorm = slange_("1", m, n, &a[a_offset], lda, &work[1]);
    eps = slamch_("Precision");

    if (anorm <= 0.f) {
	if (*resid != 0.f) {
	    *resid = 1.f / eps;
	}
    } else {
	if (anorm >= *resid) {
	    *resid = *resid / anorm / ((real) (*n) * eps);
	} else {
	    if (anorm < 1.f) {
/* Computing MIN */
		r__1 = *resid, r__2 = (real) (*n) * anorm;
		*resid = dmin(r__1,r__2) / anorm / ((real) (*n) * eps);
	    } else {
/* Computing MIN */
		r__1 = *resid / anorm, r__2 = (real) (*n);
		*resid = dmin(r__1,r__2) / ((real) (*n) * eps);
	    }
	}
    }

    return 0;

/*     End of SBDT01 */

} /* sbdt01_ */