#include "blaswrap.h"
/* zbdt02.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 doublecomplex c_b7 = {-1.,-0.};
static doublecomplex c_b10 = {1.,0.};

/* Subroutine */ int zbdt02_(integer *m, integer *n, doublecomplex *b, 
	integer *ldb, doublecomplex *c__, integer *ldc, doublecomplex *u, 
	integer *ldu, doublecomplex *work, doublereal *rwork, doublereal *
	resid)
{
    /* System generated locals */
    integer b_dim1, b_offset, c_dim1, c_offset, u_dim1, u_offset, i__1;
    doublereal d__1, d__2;

    /* Local variables */
    static integer j;
    static doublereal eps, bnorm;
    extern /* Subroutine */ int zgemv_(char *, integer *, integer *, 
	    doublecomplex *, doublecomplex *, integer *, doublecomplex *, 
	    integer *, doublecomplex *, doublecomplex *, integer *), 
	    zcopy_(integer *, doublecomplex *, integer *, doublecomplex *, 
	    integer *);
    extern doublereal dlamch_(char *);
    static doublereal realmn;
    extern doublereal zlange_(char *, integer *, integer *, doublecomplex *, 
	    integer *, doublereal *), dzasum_(integer *, 
	    doublecomplex *, integer *);


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


    Purpose   
    =======   

    ZBDT02 tests the change of basis C = U' * B by computing the residual   

       RESID = norm( B - U * C ) / ( max(m,n) * norm(B) * EPS ),   

    where B and C are M by N matrices, U is an M by M orthogonal matrix,   
    and EPS is the machine precision.   

    Arguments   
    =========   

    M       (input) INTEGER   
            The number of rows of the matrices B and C and the order of   
            the matrix Q.   

    N       (input) INTEGER   
            The number of columns of the matrices B and C.   

    B       (input) COMPLEX*16 array, dimension (LDB,N)   
            The m by n matrix B.   

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

    C       (input) COMPLEX*16 array, dimension (LDC,N)   
            The m by n matrix C, assumed to contain U' * B.   

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

    U       (input) COMPLEX*16 array, dimension (LDU,M)   
            The m by m orthogonal matrix U.   

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

    WORK    (workspace) COMPLEX*16 array, dimension (M)   

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

    RESID   (output) DOUBLE PRECISION   
            RESID = norm( B - U * C ) / ( max(m,n) * norm(B) * EPS ),   

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


       Quick return if possible   

       Parameter adjustments */
    b_dim1 = *ldb;
    b_offset = 1 + b_dim1;
    b -= b_offset;
    c_dim1 = *ldc;
    c_offset = 1 + c_dim1;
    c__ -= c_offset;
    u_dim1 = *ldu;
    u_offset = 1 + u_dim1;
    u -= u_offset;
    --work;
    --rwork;

    /* Function Body */
    *resid = 0.;
    if (*m <= 0 || *n <= 0) {
	return 0;
    }
    realmn = (doublereal) max(*m,*n);
    eps = dlamch_("Precision");

/*     Compute norm( B - U * C ) */

    i__1 = *n;
    for (j = 1; j <= i__1; ++j) {
	zcopy_(m, &b[j * b_dim1 + 1], &c__1, &work[1], &c__1);
	zgemv_("No transpose", m, m, &c_b7, &u[u_offset], ldu, &c__[j * 
		c_dim1 + 1], &c__1, &c_b10, &work[1], &c__1);
/* Computing MAX */
	d__1 = *resid, d__2 = dzasum_(m, &work[1], &c__1);
	*resid = max(d__1,d__2);
/* L10: */
    }

/*     Compute norm of B. */

    bnorm = zlange_("1", m, n, &b[b_offset], ldb, &rwork[1]);

    if (bnorm <= 0.) {
	if (*resid != 0.) {
	    *resid = 1. / eps;
	}
    } else {
	if (bnorm >= *resid) {
	    *resid = *resid / bnorm / (realmn * eps);
	} else {
	    if (bnorm < 1.) {
/* Computing MIN */
		d__1 = *resid, d__2 = realmn * bnorm;
		*resid = min(d__1,d__2) / bnorm / (realmn * eps);
	    } else {
/* Computing MIN */
		d__1 = *resid / bnorm;
		*resid = min(d__1,realmn) / (realmn * eps);
	    }
	}
    }
    return 0;

/*     End of ZBDT02 */

} /* zbdt02_ */