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/* srscl.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 srscl_(integer *n, real *sa, real *sx, integer *incx)
{
real mul, cden;
logical done;
real cnum, cden1, cnum1;
extern /* Subroutine */ int sscal_(integer *, real *, real *, integer *),
slabad_(real *, real *);
extern doublereal slamch_(char *);
real bignum, smlnum;
/* -- LAPACK auxiliary routine (version 3.2) -- */
/* Univ. of Tennessee, Univ. of California Berkeley and NAG Ltd.. */
/* November 2006 */
/* .. Scalar Arguments .. */
/* .. */
/* .. Array Arguments .. */
/* .. */
/* Purpose */
/* ======= */
/* SRSCL multiplies an n-element real vector x by the real scalar 1/a. */
/* This is done without overflow or underflow as long as */
/* the final result x/a does not overflow or underflow. */
/* Arguments */
/* ========= */
/* N (input) INTEGER */
/* The number of components of the vector x. */
/* SA (input) REAL */
/* The scalar a which is used to divide each component of x. */
/* SA must be >= 0, or the subroutine will divide by zero. */
/* SX (input/output) REAL array, dimension */
/* (1+(N-1)*abs(INCX)) */
/* The n-element vector x. */
/* INCX (input) INTEGER */
/* The increment between successive values of the vector SX. */
/* > 0: SX(1) = X(1) and SX(1+(i-1)*INCX) = x(i), 1< i<= n */
/* ===================================================================== */
/* .. Parameters .. */
/* .. */
/* .. Local Scalars .. */
/* .. */
/* .. External Functions .. */
/* .. */
/* .. External Subroutines .. */
/* .. */
/* .. Intrinsic Functions .. */
/* .. */
/* .. Executable Statements .. */
/* Quick return if possible */
/* Parameter adjustments */
--sx;
/* Function Body */
if (*n <= 0) {
return 0;
}
/* Get machine parameters */
smlnum = slamch_("S");
bignum = 1.f / smlnum;
slabad_(&smlnum, &bignum);
/* Initialize the denominator to SA and the numerator to 1. */
cden = *sa;
cnum = 1.f;
L10:
cden1 = cden * smlnum;
cnum1 = cnum / bignum;
if (dabs(cden1) > dabs(cnum) && cnum != 0.f) {
/* Pre-multiply X by SMLNUM if CDEN is large compared to CNUM. */
mul = smlnum;
done = FALSE_;
cden = cden1;
} else if (dabs(cnum1) > dabs(cden)) {
/* Pre-multiply X by BIGNUM if CDEN is small compared to CNUM. */
mul = bignum;
done = FALSE_;
cnum = cnum1;
} else {
/* Multiply X by CNUM / CDEN and return. */
mul = cnum / cden;
done = TRUE_;
}
/* Scale the vector X by MUL */
sscal_(n, &mul, &sx[1], incx);
if (! done) {
goto L10;
}
return 0;
/* End of SRSCL */
} /* srscl_ */
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