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/* slargv.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"
/* Subroutine */ int slargv_(integer *n, real *x, integer *incx, real *y,
integer *incy, real *c__, integer *incc)
{
/* System generated locals */
integer i__1;
/* Builtin functions */
double sqrt(doublereal);
/* Local variables */
real f, g;
integer i__;
real t;
integer ic, ix, iy;
real tt;
/* -- LAPACK auxiliary routine (version 3.2) -- */
/* Univ. of Tennessee, Univ. of California Berkeley and NAG Ltd.. */
/* November 2006 */
/* .. Scalar Arguments .. */
/* .. */
/* .. Array Arguments .. */
/* .. */
/* Purpose */
/* ======= */
/* SLARGV generates a vector of real plane rotations, determined by */
/* elements of the real vectors x and y. For i = 1,2,...,n */
/* ( c(i) s(i) ) ( x(i) ) = ( a(i) ) */
/* ( -s(i) c(i) ) ( y(i) ) = ( 0 ) */
/* Arguments */
/* ========= */
/* N (input) INTEGER */
/* The number of plane rotations to be generated. */
/* X (input/output) REAL array, */
/* dimension (1+(N-1)*INCX) */
/* On entry, the vector x. */
/* On exit, x(i) is overwritten by a(i), for i = 1,...,n. */
/* INCX (input) INTEGER */
/* The increment between elements of X. INCX > 0. */
/* Y (input/output) REAL array, */
/* dimension (1+(N-1)*INCY) */
/* On entry, the vector y. */
/* On exit, the sines of the plane rotations. */
/* INCY (input) INTEGER */
/* The increment between elements of Y. INCY > 0. */
/* C (output) REAL array, dimension (1+(N-1)*INCC) */
/* The cosines of the plane rotations. */
/* INCC (input) INTEGER */
/* The increment between elements of C. INCC > 0. */
/* ===================================================================== */
/* .. Parameters .. */
/* .. */
/* .. Local Scalars .. */
/* .. */
/* .. Intrinsic Functions .. */
/* .. */
/* .. Executable Statements .. */
/* Parameter adjustments */
--c__;
--y;
--x;
/* Function Body */
ix = 1;
iy = 1;
ic = 1;
i__1 = *n;
for (i__ = 1; i__ <= i__1; ++i__) {
f = x[ix];
g = y[iy];
if (g == 0.f) {
c__[ic] = 1.f;
} else if (f == 0.f) {
c__[ic] = 0.f;
y[iy] = 1.f;
x[ix] = g;
} else if (dabs(f) > dabs(g)) {
t = g / f;
tt = sqrt(t * t + 1.f);
c__[ic] = 1.f / tt;
y[iy] = t * c__[ic];
x[ix] = f * tt;
} else {
t = f / g;
tt = sqrt(t * t + 1.f);
y[iy] = 1.f / tt;
c__[ic] = t * y[iy];
x[ix] = g * tt;
}
ic += *incc;
iy += *incy;
ix += *incx;
/* L10: */
}
return 0;
/* End of SLARGV */
} /* slargv_ */
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