/*--------------------------------------------------------------------
 *	$Id: fourt.c,v 1.5 2004/01/02 22:45:12 pwessel Exp $
 *
 *	Copyright (c) 1991-2004 by P. Wessel and W. H. F. Smith
 *	See COPYING file for copying and redistribution conditions.
 *
 *	This program is free software; you can redistribute it and/or modify
 *	it under the terms of the GNU General Public License as published by
 *	the Free Software Foundation; version 2 of the License.
 *
 *	This program is distributed in the hope that it will be useful,
 *	but WITHOUT ANY WARRANTY; without even the implied warranty of
 *	MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 *	GNU General Public License for more details.
 *
 *	Contact info: gmt.soest.hawaii.edu
 *--------------------------------------------------------------------*/
/*	Translation of old fourt.f FORTRAN code to C using the automatic
 *	translator f2c written by S.I. Feldman, David M. Gay, Mark W. Maimone,
 *	and N.L. Schryer.  Translated version provided by Andrew MacRae
 *	at the University of Calgary.  I've cleaned up the resulting code
 *	since much of the f2c.h include stuff was unnecessary for this
 *	function. 
 *
 *	P. Wessel
 *--------------------------------------------------------------------*/

#include "gmt.h"


typedef int integer;
typedef float real;
typedef double doublereal;


/* C-callable wrapper for fourt_ */

void GMT_fourt (float *data, int *nn, int ndim, int ksign, int iform, float *work)
            	/* Data array */
         	/* Dimension array */
         	/* Number of dimensions */
          	/* Forward(-1) or Inverse(+1) */
          	/* Real(0) or complex(1) data */
            	/* Work array */
{
	int fourt_ (real *data, integer *nn, integer *ndim, integer *ksign, integer *iform, real *work);
	(void) fourt_ (data, nn, &ndim, &ksign, &iform, work);
}

int fourt_ (real *data, integer *nn, integer *ndim, integer *ksign, integer *iform, real *work)
{

    /* System generated locals */
    integer i__1, i__2, i__3, i__4, i__5, i__6, i__7, i__8, i__9, i__10, i__11, i__12;

    /* Builtin functions */
    
    double cos(double), sin(double);

    /* Local variables */

    static integer j1rg2, idiv, irem, ipar, kmin, imin, jmin, lmax, mmax, imax, jmax;
    static integer ntwo, j1cnj, np1hf, np2hf, j1min, i1max, i1rng, j1rng, j2min, j3max;
    static integer j1max, j2max, i2max, non2t, j2stp, i, j, k, l, m, n, icase, ifact[1];
    static integer nhalf, krang, kconj, kdif, idim, ntot, kstep, k2, k3, k4, nprev, iquot;
    static integer i2, i1, i3, j3, k1, j2, j1, if_, np0, np1, np2, ifp1, ifp2, non2;
    
    static real theta, oldsi, tempi, oldsr, sinth, difi, difr, sumi, sumr, tempr, twopi;
    static real wstpi, wstpr, twowr, wi, wr, u1i, w2i, w3i, u2i, u3i, u4i, t2i, u1r;
    static real u2r, u3r, w2r, w3r, u4r, t2r, t3r, t3i, t4r, t4i;
    static doublereal wrd, wid;

/*---------------------------------------------------------------------------
       ARGUMENTS :  
		DATA - COMPLEX ARRAY, LENGTH NN                            
		NN - ARRAY OF NUMBER OF POINTS IN EACH DIMENSION           
		NDIM - NUMBER OF DIMENSIONS (FOR OUR PURPOSES, NDIM=1)     
		KSIGN - +1 FOR INVERSE TRANSFORM (FREQ TO TIME DOMAIN)     
		        -1 FOR FORWARD TRANSFORM (TIME TO FREQ DOMAIN)     
		IFORM - 0 REAL DATA                                        
			+1 COMPLEX DATA                                    
		WORK - 0 IF ALL DIMENSIONS ARE RADIX 2                     
		       COMPLEX ARRAY, LARGE AS LARGEST NON-RADIX 2 DIMENSI0N

	PROGRAM BY NORMAN BRENNER FROM THE BASIC PROGRAM BY CHARLES        
	RADER.  RALPH ALTER SUGGESTED THE IDEA FOR THE DIGIT REVERSAL.     
	MIT LINCOLN LABORATORY, AUGUST 1967.
	
---------------------------------------------------------------------------*/

   /* Parameter adjustments */
    --work;
    --nn;
    --data;

    /* Function Body */
    wr = wi = wstpr = wstpi = (real)0.0;
    twopi = (real)6.283185307;
    if (*ndim - 1 >= 0) {
	goto L1;
    } else {
	goto L920;
    }
L1:
    ntot = 2;
    i__1 = *ndim;
    for (idim = 1; idim <= i__1; ++idim) {
	if (nn[idim] <= 0) {
	    goto L920;
	} else {
	    goto L2;
	}
L2:
	ntot *= nn[idim];
    }
    np1 = 2;
    i__1 = *ndim;
    for (idim = 1; idim <= i__1; ++idim) {
	n = nn[idim];
	np2 = np1 * n;
	if ((i__2 = n - 1) < 0) {
	    goto L920;
	} else if (i__2 == 0) {
	    goto L900;
	} else {
	    goto L5;
	}
L5:
	m = n;
	ntwo = np1;
	if_ = 1;
	idiv = 2;
L10:
	iquot = m / idiv;
	irem = m - idiv * iquot;
	if (iquot - idiv >= 0) {
	    goto L11;
	} else {
	    goto L50;
	}
L11:
	if (irem != 0) {
	    goto L20;
	} else {
	    goto L12;
	}
L12:
	ntwo += ntwo;
	m = iquot;
	goto L10;
L20:
	idiv = 3;
L30:
	iquot = m / idiv;
	irem = m - idiv * iquot;
	if (iquot - idiv >= 0) {
	    goto L31;
	} else {
	    goto L60;
	}
L31:
	if (irem != 0) {
	    goto L40;
	} else {
	    goto L32;
	}
L32:
	ifact[if_ - 1] = idiv;
	++if_;
	m = iquot;
	goto L30;
L40:
	idiv += 2;
	goto L30;
L50:
	if (irem != 0) {
	    goto L60;
	} else {
	    goto L51;
	}
L51:
	ntwo += ntwo;
	goto L70;
L60:
	ifact[if_ - 1] = m;
L70:
	non2 = np1 * (np2 / ntwo);
	icase = 1;
	if (idim - 4 >= 0) {
	    goto L90;
	} else {
	    goto L71;
	}
L71:
	if (*iform <= 0) {
	    goto L72;
	} else {
	    goto L90;
	}
L72:
	icase = 2;
	if (idim - 1 <= 0) {
	    goto L73;
	} else {
	    goto L90;
	}
L73:
	icase = 3;
	if (ntwo - np1 <= 0) {
	    goto L90;
	} else {
	    goto L74;
	}
L74:
	icase = 4;
	ntwo /= 2;
	n /= 2;
	np2 /= 2;
	ntot /= 2;
	i = 3;
	i__2 = ntot;
	for (j = 2; j <= i__2; ++j) {
	    data[j] = data[i];
/* L80: */
	    i += 2;
	}
L90:
	i1rng = np1;
	if (icase - 2 != 0) {
	    goto L100;
	} else {
	    goto L95;
	}
L95:
	i1rng = np0 * (nprev / 2 + 1);
L100:
	if (ntwo - np1 <= 0) {
	    goto L600;
	} else {
	    goto L110;
	}
L110:
	np2hf = np2 / 2;
	j = 1;
	i__2 = np2;
	i__3 = non2;
	for (i2 = 1; i__3 < 0 ? i2 >= i__2 : i2 <= i__2; i2 += i__3)  
{
	    if (j - i2 >= 0) {
		goto L130;
	    } else {
		goto L120;
	    }
L120:
	    i1max = i2 + non2 - 2;
	    i__4 = i1max;
	    for (i1 = i2; i1 <= i__4; i1 += 2) {
		i__5 = ntot;
		i__6 = np2;
		for (i3 = i1; i__6 < 0 ? i3 >= i__5 : i3 <= i__5; i3  
+= i__6) 

			{
		    j3 = j + i3 - i2;
		    tempr = data[i3];
		    tempi = data[i3 + 1];
		    data[i3] = data[j3];
		    data[i3 + 1] = data[j3 + 1];
		    data[j3] = tempr;
/* L125: */
		    data[j3 + 1] = tempi;
		}
	    }
L130:
	    m = np2hf;
L140:
	    if (j - m <= 0) {
		goto L150;
	    } else {
		goto L145;
	    }
L145:
	    j -= m;
	    m /= 2;
	    if (m - non2 >= 0) {
		goto L140;
	    } else {
		goto L150;
	    }
L150:
	    j += m;
	}
	non2t = non2 + non2;
	ipar = ntwo / np1;
L310:
	if ((i__3 = ipar - 2) < 0) {
	    goto L350;
	} else if (i__3 == 0) {
	    goto L330;
	} else {
	    goto L320;
	}
L320:
	ipar /= 4;
	goto L310;
L330:
	i__3 = i1rng;
	for (i1 = 1; i1 <= i__3; i1 += 2) {
	    i__2 = non2;
	    i__6 = np1;
	    for (j3 = i1; i__6 < 0 ? j3 >= i__2 : j3 <= i__2; j3 +=  
i__6) {
		i__5 = ntot;
		i__4 = non2t;
		for (k1 = j3; i__4 < 0 ? k1 >= i__5 : k1 <= i__5; k1  
+= i__4) 

			{
		    k2 = k1 + non2;
		    tempr = data[k2];
		    tempi = data[k2 + 1];
		    data[k2] = data[k1] - tempr;
		    data[k2 + 1] = data[k1 + 1] - tempi;
		    data[k1] += tempr;
/* L340: */
		    data[k1 + 1] += tempi;
		}
	    }
	}
L350:
	mmax = non2;
L360:
	if (mmax - np2hf >= 0) {
	    goto L600;
	} else {
	    goto L370;
	}
L370:
/* Computing MAX */
	i__4 = non2t, i__5 = mmax / 2;
	lmax = MAX(i__4,i__5);
	if (mmax - non2 <= 0) {
	    goto L405;
	} else {
	    goto L380;
	}
L380:
	theta = -twopi * (real) non2 / (real) (mmax <<  
2);
	if (*ksign >= 0) {
	    goto L390;
	} else {
	    goto L400;
	}
L390:
	theta = -theta;
L400:
	sincos ((doublereal)theta, &wid, &wrd);
	wr = (real)wrd;
	wi = (real)wid;
	wstpr = (real)-2.0 * wi * wi;
	wstpi = (real)2.0 * wr * wi;
L405:
	i__4 = lmax;
	i__5 = non2t;
	for (l = non2; i__5 < 0 ? l >= i__4 : l <= i__4; l += i__5) {
	    m = l;
	    if (mmax - non2 <= 0) {
		goto L420;
	    } else {
		goto L410;
	    }
L410:
	    w2r = wr * wr - wi * wi;
	    w2i = (real)(wr * 2.0 * wi);
	    w3r = w2r * wr - w2i * wi;
	    w3i = w2r * wi + w2i * wr;
L420:
	    i__6 = i1rng;
	    for (i1 = 1; i1 <= i__6; i1 += 2) {
		i__2 = non2;
		i__3 = np1;
		for (j3 = i1; i__3 < 0 ? j3 >= i__2 : j3 <= i__2; j3  
+= i__3) 

			{
		    kmin = j3 + ipar * m;
		    if (mmax - non2 <= 0) {
			goto L430;
		    } else {
			goto L440;
		    }
L430:
		    kmin = j3;
L440:
		    kdif = ipar * mmax;
L450:
		    kstep = kdif << 2;
		    i__7 = ntot;
		    i__8 = kstep;
		    for (k1 = kmin; i__8 < 0 ? k1 >= i__7 : k1 <=  
i__7; k1 += 

			    i__8) {
			k2 = k1 + kdif;
			k3 = k2 + kdif;
			k4 = k3 + kdif;
			if (mmax - non2 <= 0) {
			    goto L460;
			} else {
			    goto L480;
			}
L460:
			u1r = data[k1] + data[k2];
			u1i = data[k1 + 1] + data[k2 + 1];
			u2r = data[k3] + data[k4];
			u2i = data[k3 + 1] + data[k4 + 1];
			u3r = data[k1] - data[k2];
			u3i = data[k1 + 1] - data[k2 + 1];
			if (*ksign >= 0) {
			    goto L475;
			} else {
			    goto L470;
			}
L470:
			u4r = data[k3 + 1] - data[k4 + 1];
			u4i = data[k4] - data[k3];
			goto L510;
L475:
			u4r = data[k4 + 1] - data[k3 + 1];
			u4i = data[k3] - data[k4];
			goto L510;
L480:
			t2r = w2r * data[k2] - w2i * data[k2 + 1];
			t2i = w2r * data[k2 + 1] + w2i * data[k2];
			t3r = wr * data[k3] - wi * data[k3 + 1];
			t3i = wr * data[k3 + 1] + wi * data[k3];
			t4r = w3r * data[k4] - w3i * data[k4 + 1];
			t4i = w3r * data[k4 + 1] + w3i * data[k4];
			u1r = data[k1] + t2r;
			u1i = data[k1 + 1] + t2i;
			u2r = t3r + t4r;
			u2i = t3i + t4i;
			u3r = data[k1] - t2r;
			u3i = data[k1 + 1] - t2i;
			if (*ksign >= 0) {
			    goto L500;
			} else {
			    goto L490;
			}
L490:
			u4r = t3i - t4i;
			u4i = t4r - t3r;
			goto L510;
L500:
			u4r = t4i - t3i;
			u4i = t3r - t4r;
L510:
			data[k1] = u1r + u2r;
			data[k1 + 1] = u1i + u2i;
			data[k2] = u3r + u4r;
			data[k2 + 1] = u3i + u4i;
			data[k3] = u1r - u2r;
			data[k3 + 1] = u1i - u2i;
			data[k4] = u3r - u4r;
/* L520: */
			data[k4 + 1] = u3i - u4i;
		    }
		    kmin = ((kmin - j3) << 2) + j3;
		    kdif = kstep;
		    if (kdif - np2 >= 0) {
			goto L530;
		    } else {
			goto L450;
		    }
L530:
		    ;
		}
	    }
	    m = mmax - m;
	    if (*ksign >= 0) {
		goto L550;
	    } else {
		goto L540;
	    }
L540:
	    tempr = wr;
	    wr = -wi;
	    wi = -tempr;
	    goto L560;
L550:
	    tempr = wr;
	    wr = wi;
	    wi = tempr;
L560:
	    if (m - lmax <= 0) {
		goto L565;
	    } else {
		goto L410;
	    }
L565:
	    tempr = wr;
	    wr = wr * wstpr - wi * wstpi + wr;
/* L570: */
	    wi = wi * wstpr + tempr * wstpi + wi;
	}
	ipar = 3 - ipar;
	mmax += mmax;
	goto L360;
L600:
	if (ntwo - np2 >= 0) {
	    goto L700;
	} else {
	    goto L605;
	}
L605:
	ifp1 = non2;
	if_ = 1;
	np1hf = np1 / 2;
L610:
	ifp2 = ifp1 / ifact[if_ - 1];
	j1rng = np2;
	if (icase - 3 != 0) {
	    goto L612;
	} else {
	    goto L611;
	}
L611:
	j1rng = (np2 + ifp1) / 2;
	j2stp = np2 / ifact[if_ - 1];
	j1rg2 = (j2stp + ifp2) / 2;
L612:
	j2min = ifp2 + 1;
	if (ifp1 - np2 >= 0) {
	    goto L640;
	} else {
	    goto L615;
	}
L615:
	i__5 = ifp1;
	i__4 = ifp2;
	for (j2 = j2min; i__4 < 0 ? j2 >= i__5 : j2 <= i__5; j2 +=  
i__4) {
	    theta = -twopi * (real) (j2 - 1) / (real)  
np2;
	    if (*ksign >= 0) {
		goto L620;
	    } else {
		goto L625;
	    }
L620:
	    theta = -theta;
L625:
	    sinth = (real)sin((double)(0.5 * theta));
	    wstpr = sinth * (real)(-2. * sinth);
	    wstpi = (real)sin((double)theta);
	    wr = wstpr + (real)1.0;
	    wi = wstpi;
	    j1min = j2 + ifp1;
	    i__3 = j1rng;
	    i__2 = ifp1;
	    for (j1 = j1min; i__2 < 0 ? j1 >= i__3 : j1 <= i__3; j1  
+= i__2) {

		i1max = j1 + i1rng - 2;
		i__6 = i1max;
		for (i1 = j1; i1 <= i__6; i1 += 2) {
		    i__8 = ntot;
		    i__7 = np2;
		    for (i3 = i1; i__7 < 0 ? i3 >= i__8 : i3 <= i__8;  
i3 += 

			    i__7) {
			j3max = i3 + ifp2 - np1;
			i__9 = j3max;
			i__10 = np1;
			for (j3 = i3; i__10 < 0 ? j3 >= i__9 : j3 <=  
i__9; j3 

				+= i__10) {
			    tempr = data[j3];
			    data[j3] = data[j3] * wr - data[j3 + 1] *  
wi;
/* L630: */
			    data[j3 + 1] = tempr * wi + data[j3 + 1]  
* wr;
			}
		    }
		}
		tempr = wr;
		wr = wr * wstpr - wi * wstpi + wr;
/* L635: */
		wi = tempr * wstpi + wi * wstpr + wi;
	    }
	}
L640:
	theta = -twopi / (real) ifact[if_ - 1];
	if (*ksign >= 0) {
	    goto L645;
	} else {
	    goto L650;
	}
L645:
	theta = -theta;
L650:
	sinth = (real)sin((double)(0.5 * theta));
	wstpr = sinth * (real)(-2. * sinth);
	wstpi = (real)sin((double)theta);
	kstep = (n << 1) / ifact[if_ - 1];
	krang = kstep * (ifact[if_ - 1] / 2) + 1;
	i__2 = i1rng;
	for (i1 = 1; i1 <= i__2; i1 += 2) {
	    i__3 = ntot;
	    i__4 = np2;
	    for (i3 = i1; i__4 < 0 ? i3 >= i__3 : i3 <= i__3; i3 +=  
i__4) {
		i__5 = krang;
		i__10 = kstep;
		for (kmin = 1; i__10 < 0 ? kmin >= i__5 : kmin <=  
i__5; kmin 

			+= i__10) {
		    j1max = i3 + j1rng - ifp1;
		    i__9 = j1max;
		    i__7 = ifp1;
		    for (j1 = i3; i__7 < 0 ? j1 >= i__9 : j1 <= i__9;  
j1 += 

			    i__7) {
			j3max = j1 + ifp2 - np1;
			i__8 = j3max;
			i__6 = np1;
			for (j3 = j1; i__6 < 0 ? j3 >= i__8 : j3 <=  
i__8; j3 

				+= i__6) {
			    j2max = j3 + ifp1 - ifp2;
			    k = kmin + (j3 - j1 + (j1 - i3) /  
ifact[if_ - 1]) 

				    / np1hf;
			    if (kmin - 1 <= 0) {
				goto L655;
			    } else {
				goto L665;
			    }
L655:
			    sumr = (real)0.0;
			    sumi = (real)0.0;
			    i__11 = j2max;
			    i__12 = ifp2;
			    for (j2 = j3; i__12 < 0 ? j2 >= i__11 :  
j2 <= 

				    i__11; j2 += i__12) {
				sumr += data[j2];
/* L660: */
				sumi += data[j2 + 1];
			    }
			    work[k] = sumr;
			    work[k + 1] = sumi;
			    goto L680;
L665:
			    kconj = k + ((n - kmin + 1) << 1);
			    j2 = j2max;
			    sumr = data[j2];
			    sumi = data[j2 + 1];
			    oldsr = (real)0.0;
			    oldsi = (real)0.0;
			    j2 -= ifp2;
L670:
			    tempr = sumr;
			    tempi = sumi;
			    sumr = twowr * sumr - oldsr + data[j2];
			    sumi = twowr * sumi - oldsi + data[j2 +  
1];
			    oldsr = tempr;
			    oldsi = tempi;
			    j2 -= ifp2;
			    if (j2 - j3 <= 0) {
				goto L675;
			    } else {
				goto L670;
			    }
L675:
			    tempr = wr * sumr - oldsr + data[j2];
			    tempi = wi * sumi;
			    work[k] = tempr - tempi;
			    work[kconj] = tempr + tempi;
			    tempr = wr * sumi - oldsi + data[j2 + 1];
			    tempi = wi * sumr;
			    work[k + 1] = tempr + tempi;
			    work[kconj + 1] = tempr - tempi;
L680:
			    ;
			}
		    }
		    if (kmin - 1 <= 0) {
			goto L685;
		    } else {
			goto L686;
		    }
L685:
		    wr = wstpr + (real)1.0;
		    wi = wstpi;
		    goto L690;
L686:
		    tempr = wr;
		    wr = wr * wstpr - wi * wstpi + wr;
		    wi = tempr * wstpi + wi * wstpr + wi;
L690:
		    twowr = wr + wr;
		}
		if (icase - 3 != 0) {
		    goto L692;
		} else {
		    goto L691;
		}
L691:
		if (ifp1 - np2 >= 0) {
		    goto L692;
		} else {
		    goto L695;
		}
L692:
		k = 1;
		i2max = i3 + np2 - np1;
		i__10 = i2max;
		i__5 = np1;
		for (i2 = i3; i__5 < 0 ? i2 >= i__10 : i2 <= i__10;  
i2 += 

			i__5) {
		    data[i2] = work[k];
		    data[i2 + 1] = work[k + 1];
/* L693: */
		    k += 2;
		}
		goto L698;
L695:
		j3max = i3 + ifp2 - np1;
		i__5 = j3max;
		i__10 = np1;
		for (j3 = i3; i__10 < 0 ? j3 >= i__5 : j3 <= i__5; j3  
+= 

			i__10) {
		    j2max = j3 + np2 - j2stp;
		    i__6 = j2max;
		    i__8 = j2stp;
		    for (j2 = j3; i__8 < 0 ? j2 >= i__6 : j2 <= i__6;  
j2 += 

			    i__8) {
			j1max = j2 + j1rg2 - ifp2;
			j1cnj = j3 + j2max + j2stp - j2;
			i__7 = j1max;
			i__9 = ifp2;
			for (j1 = j2; i__9 < 0 ? j1 >= i__7 : j1 <=  
i__7; j1 

				+= i__9) {
			    k = j1 + 1 - i3;
			    data[j1] = work[k];
			    data[j1 + 1] = work[k + 1];
			    if (j1 - j2 <= 0) {
				goto L697;
			    } else {
				goto L696;
			    }
L696:
			    data[j1cnj] = work[k];
			    data[j1cnj + 1] = -work[k + 1];
L697:
			    j1cnj -= ifp2;
			}
		    }
		}
L698:
		;
	    }
	}
	++if_;
	ifp1 = ifp2;
	if (ifp1 - np1 <= 0) {
	    goto L700;
	} else {
	    goto L610;
	}
L700:
	switch ((int)icase) {
	    case 1:  goto L900;
	    case 2:  goto L800;
	    case 3:  goto L900;
	    case 4:  goto L701;
	}
L701:
	nhalf = n;
	n += n;
	theta = -twopi / (real) n;
	if (*ksign >= 0) {
	    goto L702;
	} else {
	    goto L703;
	}
L702:
	theta = -theta;
L703:
	sinth = (real)sin((double)(0.5 * theta));
	wstpr = sinth * (real)(-2. * sinth);
	wstpi = (real)sin((double)theta);
	wr = wstpr + (real)1.0;
	wi = wstpi;
	imin = 3;
	jmin = (nhalf << 1) - 1;
	goto L725;
L710:
	j = jmin;
	i__4 = ntot;
	i__3 = np2;
	for (i = imin; i__3 < 0 ? i >= i__4 : i <= i__4; i += i__3) {
	    sumr = (real)0.5 * (data[i] + data[j]);
	    sumi = (real)0.5 * (data[i + 1] + data[j + 1]);
	    difr = (real)0.5 * (data[i] - data[j]);
	    difi = (real)0.5 * (data[i + 1] - data[j + 1]);
	    tempr = wr * sumi + wi * difr;
	    tempi = wi * sumi - wr * difr;
	    data[i] = sumr + tempr;
	    data[i + 1] = difi + tempi;
	    data[j] = sumr - tempr;
	    data[j + 1] = -difi + tempi;
/* L720: */
	    j += np2;
	}
	imin += 2;
	jmin += -2;
	tempr = wr;
	wr = wr * wstpr - wi * wstpi + wr;
	wi = tempr * wstpi + wi * wstpr + wi;
L725:
	if ((i__3 = imin - jmin) < 0) {
	    goto L710;
	} else if (i__3 == 0) {
	    goto L730;
	} else {
	    goto L740;
	}
L730:
	if (*ksign >= 0) {
	    goto L740;
	} else {
	    goto L731;
	}
L731:
	i__3 = ntot;
	i__4 = np2;
	for (i = imin; i__4 < 0 ? i >= i__3 : i <= i__3; i += i__4) {
/* L735: */
	    data[i + 1] = -data[i + 1];
	}
L740:
	np2 += np2;
	ntot += ntot;
	j = ntot + 1;
	imax = ntot / 2 + 1;
L745:
	imin = imax - (nhalf << 1);
	i = imin;
	goto L755;
L750:
	data[j] = data[i];
	data[j + 1] = -data[i + 1];
L755:
	i += 2;
	j += -2;
	if (i - imax >= 0) {
	    goto L760;
	} else {
	    goto L750;
	}
L760:
	data[j] = data[imin] - data[imin + 1];
	data[j + 1] = (real)0.0;
	if (i - j >= 0) {
	    goto L780;
	} else {
	    goto L770;
	}
L765:
	data[j] = data[i];
	data[j + 1] = data[i + 1];
L770:
	i += -2;
	j += -2;
	if (i - imin <= 0) {
	    goto L775;
	} else {
	    goto L765;
	}
L775:
	data[j] = data[imin] + data[imin + 1];
	data[j + 1] = (real)0.0;
	imax = imin;
	goto L745;
L780:
	data[1] += data[2];
	data[2] = (real)0.0;
	goto L900;
L800:
	if (i1rng - np1 >= 0) {
	    goto L900;
	} else {
	    goto L805;
	}
L805:
	i__4 = ntot;
	i__3 = np2;
	for (i3 = 1; i__3 < 0 ? i3 >= i__4 : i3 <= i__4; i3 += i__3)  
{
	    i2max = i3 + np2 - np1;
	    i__2 = i2max;
	    i__9 = np1;
	    for (i2 = i3; i__9 < 0 ? i2 >= i__2 : i2 <= i__2; i2 +=  
i__9) {
		imin = i2 + i1rng;
		imax = i2 + np1 - 2;
		jmax = (i3 << 1) + np1 - imin;
		if (i2 - i3 <= 0) {
		    goto L820;
		} else {
		    goto L810;
		}
L810:
		jmax += np2;
L820:
		if (idim - 2 <= 0) {
		    goto L850;
		} else {
		    goto L830;
		}
L830:
		j = jmax + np0;
		i__7 = imax;
		for (i = imin; i <= i__7; i += 2) {
		    data[i] = data[j];
		    data[i + 1] = -data[j + 1];
/* L840: */
		    j += -2;
		}
L850:
		j = jmax;
		i__7 = imax;
		i__8 = np0;
		for (i = imin; i__8 < 0 ? i >= i__7 : i <= i__7; i +=  
i__8) {
		    data[i] = data[j];
		    data[i + 1] = -data[j + 1];
/* L860: */
		    j -= np0;
		}
	    }
	}
L900:
	np0 = np1;
	np1 = np2;
/* L910: */
	nprev = n;
    }
L920:
    return 0;
} /* fourt_ */
