#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 integer c__7 = 7;
static doublereal c_b5 = 0.;
static doublereal c_b6 = 1.;

doublereal dqrt11_(integer *m, integer *k, doublereal *a, integer *lda, 
	doublereal *tau, doublereal *work, integer *lwork)
{
    /* System generated locals */
    integer a_dim1, a_offset, i__1;
    doublereal ret_val;

    /* Local variables */
    static integer info, j;
    extern /* Subroutine */ int dorm2r_(char *, char *, integer *, integer *, 
	    integer *, doublereal *, integer *, doublereal *, doublereal *, 
	    integer *, doublereal *, integer *);
    extern doublereal dlamch_(char *), dlange_(char *, integer *, 
	    integer *, doublereal *, integer *, doublereal *);
    extern /* Subroutine */ int dlaset_(char *, integer *, integer *, 
	    doublereal *, doublereal *, doublereal *, integer *), 
	    xerbla_(char *, integer *);
    static doublereal rdummy[1];


/*  -- LAPACK routine (version 3.0) --   
       Univ. of Tennessee, Univ. of California Berkeley, NAG Ltd.,   
       Courant Institute, Argonne National Lab, and Rice University   
       September 30, 1994   


    Purpose   
    =======   

    DQRT11 computes the test ratio   

          || Q'*Q - I || / (eps * m)   

    where the orthogonal matrix Q is represented as a product of   
    elementary transformations.  Each transformation has the form   

       H(k) = I - tau(k) v(k) v(k)'   

    where tau(k) is stored in TAU(k) and v(k) is an m-vector of the form   
    [ 0 ... 0 1 x(k) ]', where x(k) is a vector of length m-k stored   
    in A(k+1:m,k).   

    Arguments   
    =========   

    M       (input) INTEGER   
            The number of rows of the matrix A.   

    K       (input) INTEGER   
            The number of columns of A whose subdiagonal entries   
            contain information about orthogonal transformations.   

    A       (input) DOUBLE PRECISION array, dimension (LDA,K)   
            The (possibly partial) output of a QR reduction routine.   

    LDA     (input) INTEGER   
            The leading dimension of the array A.   

    TAU     (input) DOUBLE PRECISION array, dimension (K)   
            The scaling factors tau for the elementary transformations as   
            computed by the QR factorization routine.   

    WORK    (workspace) DOUBLE PRECISION array, dimension (LWORK)   

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

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


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

    /* Function Body */
    ret_val = 0.;

/*     Test for sufficient workspace */

    if (*lwork < *m * *m + *m) {
	xerbla_("DQRT11", &c__7);
	return ret_val;
    }

/*     Quick return if possible */

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

    dlaset_("Full", m, m, &c_b5, &c_b6, &work[1], m);

/*     Form Q */

    dorm2r_("Left", "No transpose", m, m, k, &a[a_offset], lda, &tau[1], &
	    work[1], m, &work[*m * *m + 1], &info);

/*     Form Q'*Q */

    dorm2r_("Left", "Transpose", m, m, k, &a[a_offset], lda, &tau[1], &work[1]
	    , m, &work[*m * *m + 1], &info);

    i__1 = *m;
    for (j = 1; j <= i__1; ++j) {
	work[(j - 1) * *m + j] += -1.;
/* L10: */
    }

    ret_val = dlange_("One-norm", m, m, &work[1], m, rdummy) / ((
	    doublereal) (*m) * dlamch_("Epsilon"));

    return ret_val;

/*     End of DQRT11 */

} /* dqrt11_ */

