zlctes.c

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/* zlctes.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"
#include "blaswrap.h"

/* Table of constant values */

static doublereal c_b3 = 1.;

logical zlctes_(doublecomplex *z__, doublecomplex *d__)
{
    /* System generated locals */
    doublereal d__1, d__2, d__3, d__4;
    logical ret_val;

    /* Builtin functions */
    double d_imag(doublecomplex *), d_sign(doublereal *, doublereal *);

    /* Local variables */
    doublereal zmax;


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

/*     .. Scalar Arguments .. */
/*     .. */

/*  Purpose */
/*  ======= */

/*  ZLCTES returns .TRUE. if the eigenvalue Z/D is to be selected */
/*  (specifically, in this subroutine, if the real part of the */
/*  eigenvalue is negative), and otherwise it returns .FALSE.. */

/*  It is used by the test routine ZDRGES to test whether the driver */
/*  routine ZGGES succesfully sorts eigenvalues. */

/*  Arguments */
/*  ========= */

/*  Z       (input) COMPLEX*16 */
/*          The numerator part of a complex eigenvalue Z/D. */

/*  D       (input) COMPLEX*16 */
/*          The denominator part of a complex eigenvalue Z/D. */

/*  ===================================================================== */

/*     .. Parameters .. */

/*     .. */
/*     .. Local Scalars .. */
/*     .. */
/*     .. Intrinsic Functions .. */
/*     .. */
/*     .. Executable Statements .. */

    if (d__->r == 0. && d__->i == 0.) {
        ret_val = z__->r < 0.;
    } else {
        if (z__->r == 0. || d__->r == 0.) {
            d__1 = d_imag(z__);
            d__2 = d_imag(d__);
            ret_val = d_sign(&c_b3, &d__1) != d_sign(&c_b3, &d__2);
        } else if (d_imag(z__) == 0. || d_imag(d__) == 0.) {
            d__1 = z__->r;
            d__2 = d__->r;
            ret_val = d_sign(&c_b3, &d__1) != d_sign(&c_b3, &d__2);
        } else {
/* Computing MAX */
            d__3 = (d__1 = z__->r, abs(d__1)), d__4 = (d__2 = d_imag(z__), 
                    abs(d__2));
            zmax = max(d__3,d__4);
            ret_val = z__->r / zmax * d__->r + d_imag(z__) / zmax * d_imag(
                    d__) < 0.;
        }
    }

    return ret_val;

/*     End of ZLCTES */

} /* zlctes_ */