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/* blas/srotg.f -- translated by f2c (version 20050501).
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
*/
#ifdef __cplusplus
extern "C" {
#endif
#include "v3p_netlib.h"
/* Table of constant values */
static real c_b4 = (float)1.;
/*< subroutine srotg(sa,sb,c,s) >*/
/* 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;
/* construct givens plane rotation. */
/* jack dongarra, linpack, 3/11/78. */
/*< real sa,sb,c,s,roe,scale,r,z >*/
/*< roe = sb >*/
roe = *sb;
/*< if( abs(sa) .gt. abs(sb) ) roe = sa >*/
if (dabs(*sa) > dabs(*sb)) {
roe = *sa;
}
/*< scale = abs(sa) + abs(sb) >*/
scale = dabs(*sa) + dabs(*sb);
/*< if( scale .ne. 0.0 ) go to 10 >*/
if (scale != (float)0.) {
goto L10;
}
/*< c = 1.0 >*/
*c__ = (float)1.;
/*< s = 0.0 >*/
*s = (float)0.;
/*< r = 0.0 >*/
r__ = (float)0.;
/*< z = 0.0 >*/
z__ = (float)0.;
/*< go to 20 >*/
goto L20;
/*< 10 r = scale*sqrt((sa/scale)**2 + (sb/scale)**2) >*/
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 = sign(1.0,roe)*r >*/
r__ = r_sign(&c_b4, &roe) * r__;
/*< c = sa/r >*/
*c__ = *sa / r__;
/*< s = sb/r >*/
*s = *sb / r__;
/*< z = 1.0 >*/
z__ = (float)1.;
/*< if( abs(sa) .gt. abs(sb) ) z = s >*/
if (dabs(*sa) > dabs(*sb)) {
z__ = *s;
}
/*< if( abs(sb) .ge. abs(sa) .and. c .ne. 0.0 ) z = 1.0/c >*/
if (dabs(*sb) >= dabs(*sa) && *c__ != (float)0.) {
z__ = (float)1. / *c__;
}
/*< 20 sa = r >*/
L20:
*sa = r__;
/*< sb = z >*/
*sb = z__;
/*< return >*/
return 0;
/*< end >*/
} /* srotg_ */
#ifdef __cplusplus
}
#endif
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