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/* srotg.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 real c_b4 = 1.f;
/* Subroutine */ int srotg_(real *sa, real *sb, real *c__, real *s)
{
/* System generated locals */
real r__1, r__2;
/* Builtin functions */
double sqrt(doublereal), r_sign(real *, real *);
/* Local variables */
real r__, z__, roe, scale;
/* .. Scalar Arguments .. */
/* .. */
/* Purpose */
/* ======= */
/* construct givens plane rotation. */
/* jack dongarra, linpack, 3/11/78. */
/* .. Local Scalars .. */
/* .. */
/* .. Intrinsic Functions .. */
/* .. */
roe = *sb;
if (dabs(*sa) > dabs(*sb)) {
roe = *sa;
}
scale = dabs(*sa) + dabs(*sb);
if (scale != 0.f) {
goto L10;
}
*c__ = 1.f;
*s = 0.f;
r__ = 0.f;
z__ = 0.f;
goto L20;
L10:
/* Computing 2nd power */
r__1 = *sa / scale;
/* Computing 2nd power */
r__2 = *sb / scale;
r__ = scale * sqrt(r__1 * r__1 + r__2 * r__2);
r__ = r_sign(&c_b4, &roe) * r__;
*c__ = *sa / r__;
*s = *sb / r__;
z__ = 1.f;
if (dabs(*sa) > dabs(*sb)) {
z__ = *s;
}
if (dabs(*sb) >= dabs(*sa) && *c__ != 0.f) {
z__ = 1.f / *c__;
}
L20:
*sa = r__;
*sb = z__;
return 0;
} /* srotg_ */
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