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/* temperton/setdgpfa.f -- translated by f2c (version 20050501).
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"
/* Table of constant values */
static integer c__2 = 2;
static integer c__3 = 3;
static integer c__5 = 5;
/* SUBROUTINE 'SETDGPFA' */
/* SETUP ROUTINE FOR SELF-SORTING IN-PLACE */
/* GENERALIZED PRIME FACTOR (COMPLEX) FFT [DGPFA] */
/* CALL SETDGPFA(TRIGS,N,NPQR,INFO) */
/* INPUT : */
/* ----- */
/* N IS THE LENGTH OF THE TRANSFORMS. N MUST BE OF THE FORM: */
/* ----------------------------------- */
/* N = (2**IP) * (3**IQ) * (5**IR) */
/* ----------------------------------- */
/* OUTPUT: */
/* ------ */
/* TRIGS IS A TABLE OF TWIDDLE FACTORS, */
/* OF LENGTH 2*IPQR (DOUBLE PRECISION) WORDS, WHERE: */
/* -------------------------------------- */
/* IPQR = (2**IP) + (3**IQ) + (5**IR) */
/* -------------------------------------- */
/* NPQR = THREE INTEGERS HOLDING IP, IQ, IR */
/* INFO = SET TO 0 ON SUCCESS AND -1 ON FAILURE */
/* WRITTEN BY CLIVE TEMPERTON 1990 */
/* ---------------------------------------------------------------------- */
/*< SUBROUTINE SETDGPFA(TRIGS,N,NPQR,INFO) >*/
/* Subroutine */ int setdgpfa_(doublereal *trigs, integer *n, integer *npqr,
integer *info)
{
/* System generated locals */
integer i__1;
/* Builtin functions */
integer pow_ii(integer *, integer *);
double asin(doublereal), cos(doublereal), sin(doublereal);
/* Local variables */
integer i__, k, kk, ni, nj[3], ll, ip, iq, nn, ir;
doublereal del;
integer ifac, kink, irot;
doublereal angle, twopi;
/*< DOUBLE PRECISION TRIGS(*) >*/
/*< INTEGER N, NPQR(3), INFO >*/
/*< DIMENSION NJ(3) >*/
/*< DOUBLE PRECISION DEL >*/
/*< DOUBLE PRECISION ANGLE, TWOPI >*/
/*< INFO = 0 >*/
/* Parameter adjustments */
--npqr;
--trigs;
/* Function Body */
*info = 0;
/* DECOMPOSE N INTO FACTORS 2,3,5 */
/* ------------------------------ */
/*< NN = N >*/
nn = *n;
/*< IFAC = 2 >*/
ifac = 2;
/*< DO 30 LL = 1 , 3 >*/
for (ll = 1; ll <= 3; ++ll) {
/*< KK = 0 >*/
kk = 0;
/*< 10 CONTINUE >*/
L10:
/*< IF (MOD(NN,IFAC).NE.0) GO TO 20 >*/
if (nn % ifac != 0) {
goto L20;
}
/*< KK = KK + 1 >*/
++kk;
/*< NN = NN / IFAC >*/
nn /= ifac;
/*< GO TO 10 >*/
goto L10;
/*< 20 CONTINUE >*/
L20:
/*< NPQR(LL) = KK >*/
npqr[ll] = kk;
/*< IFAC = IFAC + LL >*/
ifac += ll;
/*< 30 CONTINUE >*/
/* L30: */
}
/*< IF (NN.NE.1) THEN >*/
if (nn != 1) {
/* WRITE(6,40) N */
/* 40 FORMAT(' *** WARNING!!!',I10,' IS NOT A LEGAL VALUE OF N ***') */
/*< INFO = -1 >*/
*info = -1;
/*< RETURN >*/
return 0;
/*< ENDIF >*/
}
/*< IP = NPQR(1) >*/
ip = npqr[1];
/*< IQ = NPQR(2) >*/
iq = npqr[2];
/*< IR = NPQR(3) >*/
ir = npqr[3];
/* COMPUTE LIST OF ROTATED TWIDDLE FACTORS */
/* --------------------------------------- */
/*< NJ(1) = 2**IP >*/
nj[0] = pow_ii(&c__2, &ip);
/*< NJ(2) = 3**IQ >*/
nj[1] = pow_ii(&c__3, &iq);
/*< NJ(3) = 5**IR >*/
nj[2] = pow_ii(&c__5, &ir);
/*< TWOPI = 4.0 * ASIN(1.0) >*/
twopi = asin((float)1.) * (float)4.;
/*< I = 1 >*/
i__ = 1;
/*< DO 60 LL = 1 , 3 >*/
for (ll = 1; ll <= 3; ++ll) {
/*< NI = NJ(LL) >*/
ni = nj[ll - 1];
/*< IF (NI.EQ.1) GO TO 60 >*/
if (ni == 1) {
goto L60;
}
/*< DEL = TWOPI / DFLOAT(NI) >*/
del = twopi / (doublereal) ni;
/*< IROT = N / NI >*/
irot = *n / ni;
/*< KINK = MOD(IROT,NI) >*/
kink = irot % ni;
/*< KK = 0 >*/
kk = 0;
/*< DO 50 K = 1 , NI >*/
i__1 = ni;
for (k = 1; k <= i__1; ++k) {
/*< ANGLE = DFLOAT(KK) * DEL >*/
angle = (doublereal) kk * del;
/*< TRIGS(I) = COS(ANGLE) >*/
trigs[i__] = cos(angle);
/*< TRIGS(I+1) = SIN(ANGLE) >*/
trigs[i__ + 1] = sin(angle);
/*< I = I + 2 >*/
i__ += 2;
/*< KK = KK + KINK >*/
kk += kink;
/*< IF (KK.GT.NI) KK = KK - NI >*/
if (kk > ni) {
kk -= ni;
}
/*< 50 CONTINUE >*/
/* L50: */
}
/*< 60 CONTINUE >*/
L60:
;
}
/*< RETURN >*/
return 0;
/*< END >*/
} /* setdgpfa_ */
#ifdef __cplusplus
}
#endif
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