#include "blaswrap.h"
/* cget04.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;

/* Subroutine */ int cget04_(integer *n, integer *nrhs, complex *x, integer *
	ldx, complex *xact, integer *ldxact, real *rcond, real *resid)
{
    /* System generated locals */
    integer x_dim1, x_offset, xact_dim1, xact_offset, i__1, i__2, i__3, i__4;
    real r__1, r__2, r__3, r__4;
    complex q__1, q__2;

    /* Builtin functions */
    double r_imag(complex *);

    /* Local variables */
    static integer i__, j, ix;
    static real eps, xnorm;
    extern integer icamax_(integer *, complex *, integer *);
    static real diffnm;
    extern doublereal slamch_(char *);


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


    Purpose   
    =======   

    CGET04 computes the difference between a computed solution and the   
    true solution to a system of linear equations.   

    RESID =  ( norm(X-XACT) * RCOND ) / ( norm(XACT) * EPS ),   
    where RCOND is the reciprocal of the condition number and EPS is the   
    machine epsilon.   

    Arguments   
    =========   

    N       (input) INTEGER   
            The number of rows of the matrices X and XACT.  N >= 0.   

    NRHS    (input) INTEGER   
            The number of columns of the matrices X and XACT.  NRHS >= 0.   

    X       (input) COMPLEX array, dimension (LDX,NRHS)   
            The computed solution vectors.  Each vector is stored as a   
            column of the matrix X.   

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

    XACT    (input) COMPLEX array, dimension (LDX,NRHS)   
            The exact solution vectors.  Each vector is stored as a   
            column of the matrix XACT.   

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

    RCOND   (input) REAL   
            The reciprocal of the condition number of the coefficient   
            matrix in the system of equations.   

    RESID   (output) REAL   
            The maximum over the NRHS solution vectors of   
            ( norm(X-XACT) * RCOND ) / ( norm(XACT) * EPS )   

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


       Quick exit if N = 0 or NRHS = 0.   

       Parameter adjustments */
    x_dim1 = *ldx;
    x_offset = 1 + x_dim1;
    x -= x_offset;
    xact_dim1 = *ldxact;
    xact_offset = 1 + xact_dim1;
    xact -= xact_offset;

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

/*     Exit with RESID = 1/EPS if RCOND is invalid. */

    eps = slamch_("Epsilon");
    if (*rcond < 0.f) {
	*resid = 1.f / eps;
	return 0;
    }

/*     Compute the maximum of   
          norm(X - XACT) / ( norm(XACT) * EPS )   
       over all the vectors X and XACT . */

    *resid = 0.f;
    i__1 = *nrhs;
    for (j = 1; j <= i__1; ++j) {
	ix = icamax_(n, &xact[j * xact_dim1 + 1], &c__1);
	i__2 = ix + j * xact_dim1;
	xnorm = (r__1 = xact[i__2].r, dabs(r__1)) + (r__2 = r_imag(&xact[ix + 
		j * xact_dim1]), dabs(r__2));
	diffnm = 0.f;
	i__2 = *n;
	for (i__ = 1; i__ <= i__2; ++i__) {
	    i__3 = i__ + j * x_dim1;
	    i__4 = i__ + j * xact_dim1;
	    q__2.r = x[i__3].r - xact[i__4].r, q__2.i = x[i__3].i - xact[i__4]
		    .i;
	    q__1.r = q__2.r, q__1.i = q__2.i;
/* Computing MAX */
	    r__3 = diffnm, r__4 = (r__1 = q__1.r, dabs(r__1)) + (r__2 = 
		    r_imag(&q__1), dabs(r__2));
	    diffnm = dmax(r__3,r__4);
/* L10: */
	}
	if (xnorm <= 0.f) {
	    if (diffnm > 0.f) {
		*resid = 1.f / eps;
	    }
	} else {
/* Computing MAX */
	    r__1 = *resid, r__2 = diffnm / xnorm * *rcond;
	    *resid = dmax(r__1,r__2);
	}
/* L20: */
    }
    if (*resid * eps < 1.f) {
	*resid /= eps;
    }

    return 0;

/*     End of CGET04 */

} /* cget04_ */