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/* lapack/complex16/zdrscl.f -- translated by f2c (version 20090411).
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"
/*< SUBROUTINE ZDRSCL( N, SA, SX, INCX ) >*/
/* Subroutine */ int zdrscl_(integer *n, doublereal *sa, doublecomplex *sx,
integer *incx)
{
doublereal mul, cden;
logical done;
doublereal cnum, cden1, cnum1;
extern /* Subroutine */ int dlabad_(doublereal *, doublereal *);
extern doublereal dlamch_(char *, ftnlen);
extern /* Subroutine */ int zdscal_(integer *, doublereal *,
doublecomplex *, integer *);
doublereal bignum, smlnum;
/* -- LAPACK auxiliary routine (version 3.2) -- */
/* -- LAPACK is a software package provided by Univ. of Tennessee, -- */
/* -- Univ. of California Berkeley, Univ. of Colorado Denver and NAG Ltd..-- */
/* November 2006 */
/* .. Scalar Arguments .. */
/*< INTEGER INCX, N >*/
/*< DOUBLE PRECISION SA >*/
/* .. */
/* .. Array Arguments .. */
/*< COMPLEX*16 SX( * ) >*/
/* .. */
/* Purpose */
/* ======= */
/* ZDRSCL multiplies an n-element complex 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) DOUBLE PRECISION */
/* 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) COMPLEX*16 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 .. */
/*< DOUBLE PRECISION ZERO, ONE >*/
/*< PARAMETER ( ZERO = 0.0D+0, ONE = 1.0D+0 ) >*/
/* .. */
/* .. Local Scalars .. */
/*< LOGICAL DONE >*/
/*< DOUBLE PRECISION BIGNUM, CDEN, CDEN1, CNUM, CNUM1, MUL, SMLNUM >*/
/* .. */
/* .. External Functions .. */
/*< DOUBLE PRECISION DLAMCH >*/
/*< EXTERNAL DLAMCH >*/
/* .. */
/* .. External Subroutines .. */
/*< EXTERNAL DLABAD, ZDSCAL >*/
/* .. */
/* .. Intrinsic Functions .. */
/*< INTRINSIC ABS >*/
/* .. */
/* .. Executable Statements .. */
/* Quick return if possible */
/*< >*/
/* Parameter adjustments */
--sx;
/* Function Body */
if (*n <= 0) {
return 0;
}
/* Get machine parameters */
/*< SMLNUM = DLAMCH( 'S' ) >*/
smlnum = dlamch_("S", (ftnlen)1);
/*< BIGNUM = ONE / SMLNUM >*/
bignum = 1. / smlnum;
/*< CALL DLABAD( SMLNUM, BIGNUM ) >*/
dlabad_(&smlnum, &bignum);
/* Initialize the denominator to SA and the numerator to 1. */
/*< CDEN = SA >*/
cden = *sa;
/*< CNUM = ONE >*/
cnum = 1.;
/*< 10 CONTINUE >*/
L10:
/*< CDEN1 = CDEN*SMLNUM >*/
cden1 = cden * smlnum;
/*< CNUM1 = CNUM / BIGNUM >*/
cnum1 = cnum / bignum;
/*< IF( ABS( CDEN1 ).GT.ABS( CNUM ) .AND. CNUM.NE.ZERO ) THEN >*/
if (abs(cden1) > abs(cnum) && cnum != 0.) {
/* Pre-multiply X by SMLNUM if CDEN is large compared to CNUM. */
/*< MUL = SMLNUM >*/
mul = smlnum;
/*< DONE = .FALSE. >*/
done = FALSE_;
/*< CDEN = CDEN1 >*/
cden = cden1;
/*< ELSE IF( ABS( CNUM1 ).GT.ABS( CDEN ) ) THEN >*/
} else if (abs(cnum1) > abs(cden)) {
/* Pre-multiply X by BIGNUM if CDEN is small compared to CNUM. */
/*< MUL = BIGNUM >*/
mul = bignum;
/*< DONE = .FALSE. >*/
done = FALSE_;
/*< CNUM = CNUM1 >*/
cnum = cnum1;
/*< ELSE >*/
} else {
/* Multiply X by CNUM / CDEN and return. */
/*< MUL = CNUM / CDEN >*/
mul = cnum / cden;
/*< DONE = .TRUE. >*/
done = TRUE_;
/*< END IF >*/
}
/* Scale the vector X by MUL */
/*< CALL ZDSCAL( N, MUL, SX, INCX ) >*/
zdscal_(n, &mul, &sx[1], incx);
/*< >*/
if (! done) {
goto L10;
}
/*< RETURN >*/
return 0;
/* End of ZDRSCL */
/*< END >*/
} /* zdrscl_ */
#ifdef __cplusplus
}
#endif
|
