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Tue, Feb 11, 16:48

srotm.c
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/* srotm.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 srotm_(integer *n, real *sx, integer *incx, real *sy,
integer *incy, real *sparam)
{
/* Initialized data */
static real zero = 0.f;
static real two = 2.f;
/* System generated locals */
integer i__1, i__2;
/* Local variables */
integer i__;
real w, z__;
integer kx, ky;
real sh11, sh12, sh21, sh22, sflag;
integer nsteps;
/* .. Scalar Arguments .. */
/* .. */
/* .. Array Arguments .. */
/* .. */
/* Purpose */
/* ======= */
/* APPLY THE MODIFIED GIVENS TRANSFORMATION, H, TO THE 2 BY N MATRIX */
/* (SX**T) , WHERE **T INDICATES TRANSPOSE. THE ELEMENTS OF SX ARE IN */
/* (DX**T) */
/* SX(LX+I*INCX), I = 0 TO N-1, WHERE LX = 1 IF INCX .GE. 0, ELSE */
/* LX = (-INCX)*N, AND SIMILARLY FOR SY USING USING LY AND INCY. */
/* 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). */
/* SEE SROTMG FOR A DESCRIPTION OF DATA STORAGE IN SPARAM. */
/* Arguments */
/* ========= */
/* N (input) INTEGER */
/* number of elements in input vector(s) */
/* SX (input/output) REAL array, dimension N */
/* double precision vector with N elements */
/* INCX (input) INTEGER */
/* storage spacing between elements of SX */
/* SY (input/output) REAL array, dimension N */
/* double precision vector with N elements */
/* INCY (input) INTEGER */
/* storage spacing between elements of SY */
/* SPARAM (input/output) REAL array, dimension 5 */
/* SPARAM(1)=SFLAG */
/* SPARAM(2)=SH11 */
/* SPARAM(3)=SH21 */
/* SPARAM(4)=SH12 */
/* SPARAM(5)=SH22 */
/* ===================================================================== */
/* .. Local Scalars .. */
/* .. */
/* .. Data statements .. */
/* Parameter adjustments */
--sparam;
--sy;
--sx;
/* Function Body */
/* .. */
sflag = sparam[1];
if (*n <= 0 || sflag + two == zero) {
goto L140;
}
if (! (*incx == *incy && *incx > 0)) {
goto L70;
}
nsteps = *n * *incx;
if (sflag < 0.f) {
goto L50;
} else if (sflag == 0) {
goto L10;
} else {
goto L30;
}
L10:
sh12 = sparam[4];
sh21 = sparam[3];
i__1 = nsteps;
i__2 = *incx;
for (i__ = 1; i__2 < 0 ? i__ >= i__1 : i__ <= i__1; i__ += i__2) {
w = sx[i__];
z__ = sy[i__];
sx[i__] = w + z__ * sh12;
sy[i__] = w * sh21 + z__;
/* L20: */
}
goto L140;
L30:
sh11 = sparam[2];
sh22 = sparam[5];
i__2 = nsteps;
i__1 = *incx;
for (i__ = 1; i__1 < 0 ? i__ >= i__2 : i__ <= i__2; i__ += i__1) {
w = sx[i__];
z__ = sy[i__];
sx[i__] = w * sh11 + z__;
sy[i__] = -w + sh22 * z__;
/* L40: */
}
goto L140;
L50:
sh11 = sparam[2];
sh12 = sparam[4];
sh21 = sparam[3];
sh22 = sparam[5];
i__1 = nsteps;
i__2 = *incx;
for (i__ = 1; i__2 < 0 ? i__ >= i__1 : i__ <= i__1; i__ += i__2) {
w = sx[i__];
z__ = sy[i__];
sx[i__] = w * sh11 + z__ * sh12;
sy[i__] = w * sh21 + z__ * sh22;
/* L60: */
}
goto L140;
L70:
kx = 1;
ky = 1;
if (*incx < 0) {
kx = (1 - *n) * *incx + 1;
}
if (*incy < 0) {
ky = (1 - *n) * *incy + 1;
}
if (sflag < 0.f) {
goto L120;
} else if (sflag == 0) {
goto L80;
} else {
goto L100;
}
L80:
sh12 = sparam[4];
sh21 = sparam[3];
i__2 = *n;
for (i__ = 1; i__ <= i__2; ++i__) {
w = sx[kx];
z__ = sy[ky];
sx[kx] = w + z__ * sh12;
sy[ky] = w * sh21 + z__;
kx += *incx;
ky += *incy;
/* L90: */
}
goto L140;
L100:
sh11 = sparam[2];
sh22 = sparam[5];
i__2 = *n;
for (i__ = 1; i__ <= i__2; ++i__) {
w = sx[kx];
z__ = sy[ky];
sx[kx] = w * sh11 + z__;
sy[ky] = -w + sh22 * z__;
kx += *incx;
ky += *incy;
/* L110: */
}
goto L140;
L120:
sh11 = sparam[2];
sh12 = sparam[4];
sh21 = sparam[3];
sh22 = sparam[5];
i__2 = *n;
for (i__ = 1; i__ <= i__2; ++i__) {
w = sx[kx];
z__ = sy[ky];
sx[kx] = w * sh11 + z__ * sh12;
sy[ky] = w * sh21 + z__ * sh22;
kx += *incx;
ky += *incy;
/* L130: */
}
L140:
return 0;
} /* srotm_ */

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