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rexec.c

/*
 * Copyright (c) 1997-1999 Massachusetts Institute of Technology
 *
 * 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., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
 *
 */

/*
 * rexec.c -- execute the fft
 */

/* $Id: rexec.c,v 1.26 1999/10/26 21:41:35 stevenj Exp $ */
#include <stdio.h>
#include <stdlib.h>

#include <fftw-int.h>
#include <rfftw.h>

void rfftw_strided_copy(int n, fftw_real *in, int ostride,
                  fftw_real *out)
{
     int i;
     fftw_real r0, r1, r2, r3;

     i = 0;
     for (; i < (n & 3); ++i) {
        out[i * ostride] = in[i];
     }
     for (; i < n; i += 4) {
        r0 = in[i];
        r1 = in[i + 1];
        r2 = in[i + 2];
        r3 = in[i + 3];
        out[i * ostride] = r0;
        out[(i + 1) * ostride] = r1;
        out[(i + 2) * ostride] = r2;
        out[(i + 3) * ostride] = r3;
     }
}

static void rexecutor_many(int n, fftw_real *in,
                     fftw_real *out,
                     fftw_plan_node *p,
                     int istride,
                     int ostride,
                     int howmany, int idist, int odist,
                     fftw_recurse_kind recurse_kind)
{
     int s;

     switch (p->type) {
       case FFTW_REAL2HC:
            {
               fftw_real2hc_codelet *codelet = p->nodeu.real2hc.codelet;

               HACK_ALIGN_STACK_ODD;
               for (s = 0; s < howmany; ++s)
                  codelet(in + s * idist, out + s * odist,
                        out + n * ostride + s * odist,
                        istride, ostride, -ostride);
               break;
            }

       case FFTW_HC2REAL:
            {
               fftw_hc2real_codelet *codelet = p->nodeu.hc2real.codelet;

               HACK_ALIGN_STACK_ODD;
               for (s = 0; s < howmany; ++s)
                  codelet(in + s * idist, in + n * istride + s * idist,
                        out + s * odist,
                        istride, -istride, ostride);
               break;
            }

       default:
            for (s = 0; s < howmany; ++s)
               rfftw_executor_simple(n, in + s * idist,
                               out + s * odist,
                               p, istride, ostride,
                               recurse_kind);
     }
}

#ifdef FFTW_ENABLE_VECTOR_RECURSE

/* rexecutor_many_vector is like rexecutor_many, but it pushes the
   howmany loop down to the leaves of the transform: */
static void rexecutor_many_vector(int n, fftw_real *in,
                          fftw_real *out,
                          fftw_plan_node *p,
                          int istride,
                          int ostride,
                          int howmany, int idist, int odist)
{
     switch (p->type) {
       case FFTW_REAL2HC:
            {
               fftw_real2hc_codelet *codelet = p->nodeu.real2hc.codelet;
               int s;

               HACK_ALIGN_STACK_ODD;
               for (s = 0; s < howmany; ++s)
                  codelet(in + s * idist, out + s * odist,
                        out + n * ostride + s * odist,
                        istride, ostride, -ostride);
               break;
            }

       case FFTW_HC2REAL:
            {
               fftw_hc2real_codelet *codelet = p->nodeu.hc2real.codelet;
               int s;

               HACK_ALIGN_STACK_ODD;
               for (s = 0; s < howmany; ++s)
                  codelet(in + s * idist, in + n * istride + s * idist,
                        out + s * odist,
                        istride, -istride, ostride);
               break;
            }

       case FFTW_HC2HC:
            {
               int r = p->nodeu.hc2hc.size;
               int m = n / r;
               int i;
               fftw_hc2hc_codelet *codelet;
               fftw_complex *W;

               switch (p->nodeu.hc2hc.dir) {
                   case FFTW_REAL_TO_COMPLEX:
                      for (i = 0; i < r; ++i)
                         rexecutor_many_vector(m, in + i * istride,
                                           out + i * (m*ostride),
                                           p->nodeu.hc2hc.recurse,
                                           istride * r, ostride,
                                           howmany, idist, odist);

                      W = p->nodeu.hc2hc.tw->twarray;
                      codelet = p->nodeu.hc2hc.codelet;
                      HACK_ALIGN_STACK_EVEN;
                      for (i = 0; i < howmany; ++i)
                         codelet(out + i * odist, 
                               W, m * ostride, m, ostride);
                      break;
                   case FFTW_COMPLEX_TO_REAL:
                      W = p->nodeu.hc2hc.tw->twarray;
                      codelet = p->nodeu.hc2hc.codelet;
                      HACK_ALIGN_STACK_EVEN;
                      for (i = 0; i < howmany; ++i)
                         codelet(in + i * idist,
                               W, m * istride, m, istride);

                      for (i = 0; i < r; ++i)
                         rexecutor_many_vector(m, in + i * (m*istride),
                                           out + i * ostride,
                                           p->nodeu.hc2hc.recurse,
                                           istride, ostride * r,
                                           howmany, idist, odist);
                      break;
                   default:
                      goto bug;
               }

               break;
            }

       case FFTW_RGENERIC:
            {
               int r = p->nodeu.rgeneric.size;
               int m = n / r;
               int i;
               fftw_rgeneric_codelet *codelet = p->nodeu.rgeneric.codelet;
               fftw_complex *W = p->nodeu.rgeneric.tw->twarray;

               switch (p->nodeu.rgeneric.dir) {
                   case FFTW_REAL_TO_COMPLEX:
                      for (i = 0; i < r; ++i)
                         rexecutor_many_vector(m, in + i * istride,
                                     out + i * (m * ostride),
                                     p->nodeu.rgeneric.recurse,
                                       istride * r, ostride,
                                           howmany, idist, odist);

                      for (i = 0; i < howmany; ++i)
                         codelet(out + i * odist, W, m, r, n, ostride);
                      break;
                   case FFTW_COMPLEX_TO_REAL:
                      for (i = 0; i < howmany; ++i)
                         codelet(in + i * idist, W, m, r, n, istride);

                      for (i = 0; i < r; ++i)
                         rexecutor_many_vector(m, in + i * m * istride,
                                           out + i * ostride,
                                     p->nodeu.rgeneric.recurse,
                                       istride, ostride * r,
                                           howmany, idist, odist);
                      break;
                   default:
                      goto bug;
               }

               break;
            }

       default:
          bug:
            fftw_die("BUG in rexecutor: invalid plan\n");
            break;
     }
}

#endif /* FFTW_ENABLE_VECTOR_RECURSE */

void rfftw_executor_simple(int n, fftw_real *in,
                     fftw_real *out,
                     fftw_plan_node *p,
                     int istride,
                     int ostride,
                     fftw_recurse_kind recurse_kind)
{
     switch (p->type) {
       case FFTW_REAL2HC:
            HACK_ALIGN_STACK_ODD;
            (p->nodeu.real2hc.codelet) (in, out, out + n * ostride,
                                istride, ostride, -ostride);
            break;

       case FFTW_HC2REAL:
            HACK_ALIGN_STACK_ODD;
            (p->nodeu.hc2real.codelet) (in, in + n * istride, out,
                                istride, -istride, ostride);
            break;

       case FFTW_HC2HC:
            {
               int r = p->nodeu.hc2hc.size;
               int m = n / r;
               /* 
                * please do resist the temptation of initializing
                * these variables here.  Doing so forces the
                * compiler to keep a live variable across the
                * recursive call.
                */
               fftw_hc2hc_codelet *codelet;
               fftw_complex *W;

               switch (p->nodeu.hc2hc.dir) {
                   case FFTW_REAL_TO_COMPLEX:
#ifdef FFTW_ENABLE_VECTOR_RECURSE
                      if (recurse_kind == FFTW_NORMAL_RECURSE)
#endif
                         rexecutor_many(m, in, out,
                                    p->nodeu.hc2hc.recurse,
                                    istride * r, ostride,
                                    r, istride, m * ostride,
                                    FFTW_NORMAL_RECURSE);
#ifdef FFTW_ENABLE_VECTOR_RECURSE
                      else
                         rexecutor_many_vector(m, in, out,
                                    p->nodeu.hc2hc.recurse,
                                    istride * r, ostride,
                                    r, istride, m * ostride);
#endif

                      W = p->nodeu.hc2hc.tw->twarray;
                      codelet = p->nodeu.hc2hc.codelet;
                      HACK_ALIGN_STACK_EVEN;
                      codelet(out, W, m * ostride, m, ostride);
                      break;
                   case FFTW_COMPLEX_TO_REAL:
                      W = p->nodeu.hc2hc.tw->twarray;
                      codelet = p->nodeu.hc2hc.codelet;
                      HACK_ALIGN_STACK_EVEN;
                      codelet(in, W, m * istride, m, istride);

#ifdef FFTW_ENABLE_VECTOR_RECURSE
                      if (recurse_kind == FFTW_NORMAL_RECURSE)
#endif
                         rexecutor_many(m, in, out,
                                    p->nodeu.hc2hc.recurse,
                                    istride, ostride * r,
                                    r, m * istride, ostride,
                                    FFTW_NORMAL_RECURSE);
#ifdef FFTW_ENABLE_VECTOR_RECURSE
                      else
                         rexecutor_many_vector(m, in, out,
                                    p->nodeu.hc2hc.recurse,
                                    istride, ostride * r,
                                    r, m * istride, ostride);
#endif
                      break;
                   default:
                      goto bug;
               }

               break;
            }

       case FFTW_RGENERIC:
            {
               int r = p->nodeu.rgeneric.size;
               int m = n / r;
               fftw_rgeneric_codelet *codelet = p->nodeu.rgeneric.codelet;
               fftw_complex *W = p->nodeu.rgeneric.tw->twarray;

               switch (p->nodeu.rgeneric.dir) {
                   case FFTW_REAL_TO_COMPLEX:
#ifdef FFTW_ENABLE_VECTOR_RECURSE
                      if (recurse_kind == FFTW_NORMAL_RECURSE)
#endif
                         rexecutor_many(m, in, out,
                                    p->nodeu.rgeneric.recurse,
                                    istride * r, ostride,
                                    r, istride, m * ostride,
                                    FFTW_NORMAL_RECURSE);
#ifdef FFTW_ENABLE_VECTOR_RECURSE
                      else
                         rexecutor_many_vector(m, in, out,
                                    p->nodeu.rgeneric.recurse,
                                    istride * r, ostride,
                                    r, istride, m * ostride);
#endif

                      codelet(out, W, m, r, n, ostride);
                      break;
                   case FFTW_COMPLEX_TO_REAL:
                      codelet(in, W, m, r, n, istride);

#ifdef FFTW_ENABLE_VECTOR_RECURSE
                      if (recurse_kind == FFTW_NORMAL_RECURSE)
#endif
                         rexecutor_many(m, in, out,
                                    p->nodeu.rgeneric.recurse,
                                    istride, ostride * r,
                                    r, m * istride, ostride,
                                    FFTW_NORMAL_RECURSE);
#ifdef FFTW_ENABLE_VECTOR_RECURSE
                      else
                         rexecutor_many_vector(m, in, out,
                                    p->nodeu.rgeneric.recurse,
                                    istride, ostride * r,
                                    r, m * istride, ostride);
#endif
                      break;
                   default:
                      goto bug;
               }

               break;
            }

       default:
          bug:
            fftw_die("BUG in rexecutor: invalid plan\n");
            break;
     }
}

static void rexecutor_simple_inplace(int n, fftw_real *in,
                             fftw_real *out,
                             fftw_plan_node *p,
                             int istride,
                             fftw_recurse_kind recurse_kind)
{
     switch (p->type) {
       case FFTW_REAL2HC:
            HACK_ALIGN_STACK_ODD;
            (p->nodeu.real2hc.codelet) (in, in, in + n * istride,
                                istride, istride, -istride);
            break;

       case FFTW_HC2REAL:
            HACK_ALIGN_STACK_ODD;
            (p->nodeu.hc2real.codelet) (in, in + n * istride, in,
                                istride, -istride, istride);
            break;

       default:
            {
               fftw_real *tmp;

               if (out)
                  tmp = out;
               else
                  tmp = (fftw_real *) fftw_malloc(n * sizeof(fftw_real));

               rfftw_executor_simple(n, in, tmp, p, istride, 1, 
                               recurse_kind);
               rfftw_strided_copy(n, tmp, istride, in);

               if (!out)
                  fftw_free(tmp);
            }
     }
}

static void rexecutor_many_inplace(int n, fftw_real *in,
                           fftw_real *out,
                           fftw_plan_node *p,
                           int istride,
                           int howmany, int idist,
                           fftw_recurse_kind recurse_kind)
{
     switch (p->type) {
       case FFTW_REAL2HC:
            {
               fftw_real2hc_codelet *codelet = p->nodeu.real2hc.codelet;
               int s;

               HACK_ALIGN_STACK_ODD;
               for (s = 0; s < howmany; ++s)
                  codelet(in + s * idist, in + s * idist,
                        in + n * istride + s * idist,
                        istride, istride, -istride);

               break;
            }

       case FFTW_HC2REAL:
            {
               fftw_hc2real_codelet *codelet = p->nodeu.hc2real.codelet;
               int s;

               HACK_ALIGN_STACK_ODD;
               for (s = 0; s < howmany; ++s)
                  codelet(in + s * idist, in + n * istride + s * idist,
                        in + s * idist,
                        istride, -istride, istride);

               break;
            }

       default:
            {
               int s;
               fftw_real *tmp;
               if (out)
                  tmp = out;
               else
                  tmp = (fftw_real *) fftw_malloc(n * sizeof(fftw_real));

               for (s = 0; s < howmany; ++s) {
                  rfftw_executor_simple(n,
                                    in + s * idist,
                                    tmp,
                                    p, istride, 1, recurse_kind);
                  rfftw_strided_copy(n, tmp, istride, in + s * idist);
               }

               if (!out)
                  fftw_free(tmp);
            }
     }
}

/* user interface */
void rfftw(fftw_plan plan, int howmany, fftw_real *in, int istride,
         int idist, fftw_real *out, int ostride, int odist)
{
     int n = plan->n;

     if (plan->flags & FFTW_IN_PLACE) {
        if (howmany == 1) {
             rexecutor_simple_inplace(n, in, out, plan->root, istride,
                              plan->recurse_kind);
        } else {
             rexecutor_many_inplace(n, in, out, plan->root, istride, howmany,
                              idist, plan->recurse_kind);
        }
     } else {
        if (howmany == 1) {
             rfftw_executor_simple(n, in, out, plan->root, istride, ostride,
                             plan->recurse_kind);
        } else {
#ifdef FFTW_ENABLE_VECTOR_RECURSE
               int vector_size = plan->vector_size;
               if (vector_size <= 1)
#endif
                rexecutor_many(n, in, out, plan->root, istride, ostride,
                           howmany, idist, odist,
                           plan->recurse_kind);
#ifdef FFTW_ENABLE_VECTOR_RECURSE
               else {
                    int s;
                    int num_vects = howmany / vector_size;
                    fftw_plan_node *root = plan->root;

                    for (s = 0; s < num_vects; ++s)
                         rexecutor_many_vector(n,
                                     in + s * (vector_size * idist),
                                     out + s * (vector_size * odist),
                                     root,
                                     istride, ostride,
                                     vector_size, idist, odist);

                    s = howmany % vector_size;
                    if (s > 0)
                         rexecutor_many(n,
                              in + num_vects * (vector_size*idist),
                              out + num_vects * (vector_size*odist),
                              root,
                              istride, ostride,
                              s, idist, odist,
                              FFTW_NORMAL_RECURSE);
               }
#endif
        }
     }
}

void rfftw_one(fftw_plan plan, fftw_real *in, fftw_real *out)
{
     int n = plan->n;

     if (plan->flags & FFTW_IN_PLACE)
        rexecutor_simple_inplace(n, in, out, plan->root, 1,
                           plan->recurse_kind);
     else
        rfftw_executor_simple(n, in, out, plan->root, 1, 1,
                        plan->recurse_kind);
}

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