#include "blaswrap.h"
/* srzt01.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__8 = 8;
static real c_b6 = 0.f;
static real c_b13 = -1.f;
static integer c__1 = 1;

doublereal srzt01_(integer *m, integer *n, real *a, real *af, integer *lda, 
	real *tau, real *work, integer *lwork)
{
    /* System generated locals */
    integer a_dim1, a_offset, af_dim1, af_offset, i__1, i__2;
    real ret_val;

    /* Local variables */
    static integer i__, j, info;
    static real norma, rwork[1];
    extern /* Subroutine */ int saxpy_(integer *, real *, real *, integer *, 
	    real *, integer *);
    extern doublereal slamch_(char *), slange_(char *, integer *, 
	    integer *, real *, integer *, real *);
    extern /* Subroutine */ int xerbla_(char *, integer *), slaset_(
	    char *, integer *, integer *, real *, real *, real *, integer *), sormrz_(char *, char *, integer *, integer *, integer *, 
	    integer *, real *, integer *, real *, real *, integer *, real *, 
	    integer *, integer *);


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


    Purpose   
    =======   

    SRZT01 returns   
         || A - R*Q || / ( M * eps * ||A|| )   
    for an upper trapezoidal A that was factored with STZRZF.   

    Arguments   
    =========   

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

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

    A       (input) REAL array, dimension (LDA,N)   
            The original upper trapezoidal M by N matrix A.   

    AF      (input) REAL array, dimension (LDA,N)   
            The output of STZRZF for input matrix A.   
            The lower triangle is not referenced.   

    LDA     (input) INTEGER   
            The leading dimension of the arrays A and AF.   

    TAU     (input) REAL array, dimension (M)   
            Details of the Householder transformations as returned by   
            STZRZF.   

    WORK    (workspace) REAL array, dimension (LWORK)   

    LWORK   (input) INTEGER   
            The length of the array WORK.  LWORK >= m*n + m*nb.   

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


       Parameter adjustments */
    af_dim1 = *lda;
    af_offset = 1 + af_dim1;
    af -= af_offset;
    a_dim1 = *lda;
    a_offset = 1 + a_dim1;
    a -= a_offset;
    --tau;
    --work;

    /* Function Body */
    ret_val = 0.f;

    if (*lwork < *m * *n + *m) {
	xerbla_("SRZT01", &c__8);
	return ret_val;
    }

/*     Quick return if possible */

    if (*m <= 0 || *n <= 0) {
	return ret_val;
    }

    norma = slange_("One-norm", m, n, &a[a_offset], lda, rwork);

/*     Copy upper triangle R */

    slaset_("Full", m, n, &c_b6, &c_b6, &work[1], m);
    i__1 = *m;
    for (j = 1; j <= i__1; ++j) {
	i__2 = j;
	for (i__ = 1; i__ <= i__2; ++i__) {
	    work[(j - 1) * *m + i__] = af[i__ + j * af_dim1];
/* L10: */
	}
/* L20: */
    }

/*     R = R * P(1) * ... *P(m) */

    i__1 = *n - *m;
    i__2 = *lwork - *m * *n;
    sormrz_("Right", "No tranpose", m, n, m, &i__1, &af[af_offset], lda, &tau[
	    1], &work[1], m, &work[*m * *n + 1], &i__2, &info);

/*     R = R - A */

    i__1 = *n;
    for (i__ = 1; i__ <= i__1; ++i__) {
	saxpy_(m, &c_b13, &a[i__ * a_dim1 + 1], &c__1, &work[(i__ - 1) * *m + 
		1], &c__1);
/* L30: */
    }

    ret_val = slange_("One-norm", m, n, &work[1], m, rwork);

    ret_val /= slamch_("Epsilon") * (real) max(*m,*n);
    if (norma != 0.f) {
	ret_val /= norma;
    }

    return ret_val;

/*     End of SRZT01 */

} /* srzt01_ */