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/* srotmg.f -- translated by f2c (version 20100827).
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 "datatypes.h"
/* Subroutine */ int srotmg_(real *sd1, real *sd2, real *sx1, real *sy1, real
*sparam)
{
/* Initialized data */
static real zero = 0.f;
static real one = 1.f;
static real two = 2.f;
static real gam = 4096.f;
static real gamsq = 16777200.f;
static real rgamsq = 5.96046e-8f;
/* Format strings */
static char fmt_120[] = "";
static char fmt_150[] = "";
static char fmt_180[] = "";
static char fmt_210[] = "";
/* System generated locals */
real r__1;
/* Local variables */
real su, sp1, sp2, sq1, sq2, sh11, sh12, sh21, sh22;
integer igo;
real sflag, stemp;
/* Assigned format variables */
static char *igo_fmt;
/* .. Scalar Arguments .. */
/* .. */
/* .. Array Arguments .. */
/* .. */
/* Purpose */
/* ======= */
/* CONSTRUCT THE MODIFIED GIVENS TRANSFORMATION MATRIX H WHICH ZEROS */
/* THE SECOND COMPONENT OF THE 2-VECTOR (SQRT(SD1)*SX1,SQRT(SD2)* */
/* SY2)**T. */
/* WITH SPARAM(1)=SFLAG, H HAS ONE OF THE FOLLOWING FORMS.. */
/* SFLAG=-1.E0 SFLAG=0.E0 SFLAG=1.E0 SFLAG=-2.E0 */
/* (SH11 SH12) (1.E0 SH12) (SH11 1.E0) (1.E0 0.E0) */
/* H=( ) ( ) ( ) ( ) */
/* (SH21 SH22), (SH21 1.E0), (-1.E0 SH22), (0.E0 1.E0). */
/* LOCATIONS 2-4 OF SPARAM CONTAIN SH11,SH21,SH12, AND SH22 */
/* RESPECTIVELY. (VALUES OF 1.E0, -1.E0, OR 0.E0 IMPLIED BY THE */
/* VALUE OF SPARAM(1) ARE NOT STORED IN SPARAM.) */
/* THE VALUES OF GAMSQ AND RGAMSQ SET IN THE DATA STATEMENT MAY BE */
/* INEXACT. THIS IS OK AS THEY ARE ONLY USED FOR TESTING THE SIZE */
/* OF SD1 AND SD2. ALL ACTUAL SCALING OF DATA IS DONE USING GAM. */
/* Arguments */
/* ========= */
/* SD1 (input/output) REAL */
/* SD2 (input/output) REAL */
/* SX1 (input/output) REAL */
/* SY1 (input) REAL */
/* SPARAM (input/output) REAL array, dimension 5 */
/* SPARAM(1)=SFLAG */
/* SPARAM(2)=SH11 */
/* SPARAM(3)=SH21 */
/* SPARAM(4)=SH12 */
/* SPARAM(5)=SH22 */
/* ===================================================================== */
/* .. Local Scalars .. */
/* .. */
/* .. Intrinsic Functions .. */
/* .. */
/* .. Data statements .. */
/* Parameter adjustments */
--sparam;
/* Function Body */
/* .. */
if (! (*sd1 < zero)) {
goto L10;
}
/* GO ZERO-H-D-AND-SX1.. */
goto L60;
L10:
/* CASE-SD1-NONNEGATIVE */
sp2 = *sd2 * *sy1;
if (! (sp2 == zero)) {
goto L20;
}
sflag = -two;
goto L260;
/* REGULAR-CASE.. */
L20:
sp1 = *sd1 * *sx1;
sq2 = sp2 * *sy1;
sq1 = sp1 * *sx1;
if (! (dabs(sq1) > dabs(sq2))) {
goto L40;
}
sh21 = -(*sy1) / *sx1;
sh12 = sp2 / sp1;
su = one - sh12 * sh21;
if (! (su <= zero)) {
goto L30;
}
/* GO ZERO-H-D-AND-SX1.. */
goto L60;
L30:
sflag = zero;
*sd1 /= su;
*sd2 /= su;
*sx1 *= su;
/* GO SCALE-CHECK.. */
goto L100;
L40:
if (! (sq2 < zero)) {
goto L50;
}
/* GO ZERO-H-D-AND-SX1.. */
goto L60;
L50:
sflag = one;
sh11 = sp1 / sp2;
sh22 = *sx1 / *sy1;
su = one + sh11 * sh22;
stemp = *sd2 / su;
*sd2 = *sd1 / su;
*sd1 = stemp;
*sx1 = *sy1 * su;
/* GO SCALE-CHECK */
goto L100;
/* PROCEDURE..ZERO-H-D-AND-SX1.. */
L60:
sflag = -one;
sh11 = zero;
sh12 = zero;
sh21 = zero;
sh22 = zero;
*sd1 = zero;
*sd2 = zero;
*sx1 = zero;
/* RETURN.. */
goto L220;
/* PROCEDURE..FIX-H.. */
L70:
if (! (sflag >= zero)) {
goto L90;
}
if (! (sflag == zero)) {
goto L80;
}
sh11 = one;
sh22 = one;
sflag = -one;
goto L90;
L80:
sh21 = -one;
sh12 = one;
sflag = -one;
L90:
switch (igo) {
case 0: goto L120;
case 1: goto L150;
case 2: goto L180;
case 3: goto L210;
}
/* PROCEDURE..SCALE-CHECK */
L100:
L110:
if (! (*sd1 <= rgamsq)) {
goto L130;
}
if (*sd1 == zero) {
goto L160;
}
igo = 0;
igo_fmt = fmt_120;
/* FIX-H.. */
goto L70;
L120:
/* Computing 2nd power */
r__1 = gam;
*sd1 *= r__1 * r__1;
*sx1 /= gam;
sh11 /= gam;
sh12 /= gam;
goto L110;
L130:
L140:
if (! (*sd1 >= gamsq)) {
goto L160;
}
igo = 1;
igo_fmt = fmt_150;
/* FIX-H.. */
goto L70;
L150:
/* Computing 2nd power */
r__1 = gam;
*sd1 /= r__1 * r__1;
*sx1 *= gam;
sh11 *= gam;
sh12 *= gam;
goto L140;
L160:
L170:
if (! (dabs(*sd2) <= rgamsq)) {
goto L190;
}
if (*sd2 == zero) {
goto L220;
}
igo = 2;
igo_fmt = fmt_180;
/* FIX-H.. */
goto L70;
L180:
/* Computing 2nd power */
r__1 = gam;
*sd2 *= r__1 * r__1;
sh21 /= gam;
sh22 /= gam;
goto L170;
L190:
L200:
if (! (dabs(*sd2) >= gamsq)) {
goto L220;
}
igo = 3;
igo_fmt = fmt_210;
/* FIX-H.. */
goto L70;
L210:
/* Computing 2nd power */
r__1 = gam;
*sd2 /= r__1 * r__1;
sh21 *= gam;
sh22 *= gam;
goto L200;
L220:
if (sflag < 0.f) {
goto L250;
} else if (sflag == 0) {
goto L230;
} else {
goto L240;
}
L230:
sparam[3] = sh21;
sparam[4] = sh12;
goto L260;
L240:
sparam[2] = sh11;
sparam[5] = sh22;
goto L260;
L250:
sparam[2] = sh11;
sparam[3] = sh21;
sparam[4] = sh12;
sparam[5] = sh22;
L260:
sparam[1] = sflag;
return 0;
} /* srotmg_ */
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