The R Project SVN R

/*
 *  R : A Computer Langage for Statistical Data Analysis
 *  Copyright (C) 1995, 1996, 1997  Robert Gentleman and Ross Ihaka
 *
 *  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; either version 2 of the License, or
 *  (at your option) any later version.
 *
 *  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.
 *
 *  You should have received a copy of the GNU General Public License
 *  along with this program; if not, write to the Free Software
 *  Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
 */

#include "Defn.h"

    /* Fourier Transform for Univariate Spatial and Time Series */

SEXP do_fft(SEXP call, SEXP op, SEXP args, SEXP env)
{
    SEXP z, d;
    int i, inv, maxf, maxmaxf, maxmaxp, maxp, n, ndims, nseg, nspn;
    double *work;
    int *iwork;
    char *vmax;

    checkArity(op, args);

    z = CAR(args);

    switch(TYPEOF(z)) {
    case INTSXP:
    case LGLSXP:
    case REALSXP:
        z = coerceVector(z, CPLXSXP);
        break;
    case CPLXSXP:
        if(NAMED(z)) z = duplicate(z);
        break;
    default:
        errorcall(call, "non-numeric argument\n");
    }
    PROTECT(z);

        /* -2 for forward transform, complex values */
        /* +2 for backward transform, complex values */

    inv = asLogical(CADR(args));
    if(inv == NA_INTEGER || inv == 0) inv = -2;
    else inv = 2;

    if(LENGTH(z) > 1) {
        vmax = vmaxget();
        if(isNull(d = getAttrib(z, R_DimSymbol))) {
                /* temporal transform */
            n = length(z);
            fft_factor(n, &maxf, &maxp);
            if(maxf == 0)
                errorcall(call, "fft factorization error\n");
            work = (double*)R_alloc(4 * maxf, sizeof(double));
            iwork = (int*)R_alloc(maxp, sizeof(int));
            fft_work(&(COMPLEX(z)[0].r), &(COMPLEX(z)[0].i),
                1, n, 1, inv, work, iwork);
        }
        else {
                /* spatial transform */
            maxmaxf = 1;
            maxmaxp = 1;
            ndims = LENGTH(d);
            for(i=0 ; i<ndims ; i++) {
                if(INTEGER(d)[i] > 1) {
                    fft_factor(INTEGER(d)[i], &maxf, &maxp);
                    if(maxf == 0)
                        errorcall(call, "fft factorization error\n");
                    if(maxf > maxmaxf) maxmaxf = maxf;
                    if(maxp > maxmaxp) maxmaxp = maxp;
                }
            }
            work = (double*)R_alloc(4 * maxmaxf, sizeof(double));
            iwork = (int*)R_alloc(maxmaxp, sizeof(int));
            nseg = LENGTH(z);
            n = 1;
            nspn = 1;
            for(i=0 ; i<ndims ; i++) {
                if(INTEGER(d)[i] > 1) {
                    nspn = nspn * n;
                    n = INTEGER(d)[i];
                    nseg = nseg/n;
                    fft_factor(n, &maxf, &maxp);
                    fft_work(&(COMPLEX(z)[0].r), &(COMPLEX(z)[0].i),
                        nseg, n, nspn, inv, work, iwork);
                }
            }
        }
        vmaxset(vmax);
    }
    UNPROTECT(1);
    return z;
}

    /* Fourier Transform for Vector-Valued Series */

SEXP do_mvfft(SEXP call, SEXP op, SEXP args, SEXP env)
{
    SEXP z, d;
    int i, inv, maxf, maxp, n, nseg, nspn, p;
    double *work;
    int *iwork;
    char *vmax;

    checkArity(op, args);

    z = CAR(args);

    d = getAttrib(z, R_DimSymbol);
    if(length(d) > 2)
        errorcall(call, "vector-valued series required\n");
    n = INTEGER(d)[0];
    p = INTEGER(d)[1];

    switch(TYPEOF(z)) {
    case INTSXP:
    case LGLSXP:
    case REALSXP:
        z = coerceVector(z, CPLXSXP);
        break;
    case CPLXSXP:
        if(NAMED(z)) z = duplicate(z);
        break;
    default:
        errorcall(call, "non-numeric argument\n");
    }
    PROTECT(z);

        /* -2 for forward transform, complex values */
        /* +2 for backward transform, complex values */

    inv = asLogical(CADR(args));
    if(inv == NA_INTEGER || inv == 0) inv = -2;
    else inv = 2;

    if(n > 1) {
        vmax = vmaxget();
        fft_factor(n, &maxf, &maxp);
        if(maxf == 0)
            errorcall(call, "fft factorization error\n");
        work = (double*)R_alloc(4 * maxf, sizeof(double));
        iwork = (int*)R_alloc(maxp, sizeof(int));
        for(i=0 ; i<p ; i++)
            fft_work(&(COMPLEX(z)[i*n].r), &(COMPLEX(z)[i*n].i),
                1, n, 1, inv, work, iwork);
        vmaxset(vmax);
    }
    UNPROTECT(1);
    return z;
}

static int ok(int n, int *f, int nf)
{
    int i;
    for(i=0 ; i<nf ; i++) {
        while(n % f[i] == 0) {
            if((n = n/f[i]) == 1) return 1;
        }
    }
    return n == 1;
}

static int nextn(int n, int *f, int nf)
{
    while(!ok(n, f, nf))
        n++;
    return n;
}

SEXP do_nextn(SEXP call, SEXP op, SEXP args, SEXP env)
{
    SEXP n, f, ans;
    int i, nn, nf;
    checkArity(op, args);
    PROTECT(n = coerceVector(CAR(args), INTSXP));
    PROTECT(f = coerceVector(CADR(args), INTSXP));
    nn = LENGTH(n);
    nf = LENGTH(f);

        /* check the factors */

    if(nf == 0) errorcall(call, "no factors\n");
    for(i=0 ; i<nf ; i++)
        if(INTEGER(f)[i] == NA_INTEGER || INTEGER(f)[i] <= 1)
            errorcall(call, "invalid factors\n");

    ans = allocVector(INTSXP, nn);
    for(i=0 ; i<nn ; i++) {
        if(INTEGER(n)[i] == NA_INTEGER) INTEGER(ans)[i] = NA_INTEGER;
        else if(INTEGER(n)[i] <= 1) INTEGER(ans)[i] = 1;
        else INTEGER(ans)[i] = nextn(INTEGER(n)[i], INTEGER(f), nf);
    }
    UNPROTECT(2);
    return ans;
}