Chris@42: /*
Chris@42:  * Copyright (c) 2003, 2007-14 Matteo Frigo
Chris@42:  * Copyright (c) 2003, 2007-14 Massachusetts Institute of Technology
Chris@42:  *
Chris@42:  * This program is free software; you can redistribute it and/or modify
Chris@42:  * it under the terms of the GNU General Public License as published by
Chris@42:  * the Free Software Foundation; either version 2 of the License, or
Chris@42:  * (at your option) any later version.
Chris@42:  *
Chris@42:  * This program is distributed in the hope that it will be useful,
Chris@42:  * but WITHOUT ANY WARRANTY; without even the implied warranty of
Chris@42:  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
Chris@42:  * GNU General Public License for more details.
Chris@42:  *
Chris@42:  * You should have received a copy of the GNU General Public License
Chris@42:  * along with this program; if not, write to the Free Software
Chris@42:  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301  USA
Chris@42:  *
Chris@42:  */
Chris@42: 
Chris@42: 
Chris@42: /* plans for RDFT of rank >= 2 (multidimensional) */
Chris@42: 
Chris@42: /* FIXME: this solver cannot strictly be applied to multidimensional
Chris@42:    DHTs, since the latter are not separable...up to rnk-1 additional
Chris@42:    post-processing passes may be required.  See also:
Chris@42: 
Chris@42:    R. N. Bracewell, O. Buneman, H. Hao, and J. Villasenor, "Fast
Chris@42:    two-dimensional Hartley transform," Proc. IEEE 74, 1282-1283 (1986).
Chris@42: 
Chris@42:    H. Hao and R. N. Bracewell, "A three-dimensional DFT algorithm
Chris@42:    using the fast Hartley transform," Proc. IEEE 75(2), 264-266 (1987).
Chris@42: */
Chris@42: 
Chris@42: #include "rdft.h"
Chris@42: 
Chris@42: typedef struct {
Chris@42:      solver super;
Chris@42:      int spltrnk;
Chris@42:      const int *buddies;
Chris@42:      size_t nbuddies;
Chris@42: } S;
Chris@42: 
Chris@42: typedef struct {
Chris@42:      plan_rdft super;
Chris@42: 
Chris@42:      plan *cld1, *cld2;
Chris@42:      const S *solver;
Chris@42: } P;
Chris@42: 
Chris@42: /* Compute multi-dimensional RDFT by applying the two cld plans
Chris@42:    (lower-rnk RDFTs). */
Chris@42: static void apply(const plan *ego_, R *I, R *O)
Chris@42: {
Chris@42:      const P *ego = (const P *) ego_;
Chris@42:      plan_rdft *cld1, *cld2;
Chris@42: 
Chris@42:      cld1 = (plan_rdft *) ego->cld1;
Chris@42:      cld1->apply(ego->cld1, I, O);
Chris@42: 
Chris@42:      cld2 = (plan_rdft *) ego->cld2;
Chris@42:      cld2->apply(ego->cld2, O, O);
Chris@42: }
Chris@42: 
Chris@42: 
Chris@42: static void awake(plan *ego_, enum wakefulness wakefulness)
Chris@42: {
Chris@42:      P *ego = (P *) ego_;
Chris@42:      X(plan_awake)(ego->cld1, wakefulness);
Chris@42:      X(plan_awake)(ego->cld2, wakefulness);
Chris@42: }
Chris@42: 
Chris@42: static void destroy(plan *ego_)
Chris@42: {
Chris@42:      P *ego = (P *) ego_;
Chris@42:      X(plan_destroy_internal)(ego->cld2);
Chris@42:      X(plan_destroy_internal)(ego->cld1);
Chris@42: }
Chris@42: 
Chris@42: static void print(const plan *ego_, printer *p)
Chris@42: {
Chris@42:      const P *ego = (const P *) ego_;
Chris@42:      const S *s = ego->solver;
Chris@42:      p->print(p, "(rdft-rank>=2/%d%(%p%)%(%p%))",
Chris@42: 	      s->spltrnk, ego->cld1, ego->cld2);
Chris@42: }
Chris@42: 
Chris@42: static int picksplit(const S *ego, const tensor *sz, int *rp)
Chris@42: {
Chris@42:      A(sz->rnk > 1); /* cannot split rnk <= 1 */
Chris@42:      if (!X(pickdim)(ego->spltrnk, ego->buddies, ego->nbuddies, sz, 1, rp))
Chris@42: 	  return 0;
Chris@42:      *rp += 1; /* convert from dim. index to rank */
Chris@42:      if (*rp >= sz->rnk) /* split must reduce rank */
Chris@42: 	  return 0;
Chris@42:      return 1;
Chris@42: }
Chris@42: 
Chris@42: static int applicable0(const solver *ego_, const problem *p_, int *rp)
Chris@42: {
Chris@42:      const problem_rdft *p = (const problem_rdft *) p_;
Chris@42:      const S *ego = (const S *)ego_;
Chris@42:      return (1
Chris@42: 	     && FINITE_RNK(p->sz->rnk) && FINITE_RNK(p->vecsz->rnk)
Chris@42: 	     && p->sz->rnk >= 2
Chris@42: 	     && picksplit(ego, p->sz, rp)
Chris@42: 	  );
Chris@42: }
Chris@42: 
Chris@42: /* TODO: revise this. */
Chris@42: static int applicable(const solver *ego_, const problem *p_, 
Chris@42: 		      const planner *plnr, int *rp)
Chris@42: {
Chris@42:      const S *ego = (const S *)ego_;
Chris@42: 
Chris@42:      if (!applicable0(ego_, p_, rp)) return 0;
Chris@42: 
Chris@42:      if (NO_RANK_SPLITSP(plnr) && (ego->spltrnk != ego->buddies[0]))
Chris@42: 	  return 0;
Chris@42: 
Chris@42:      if (NO_UGLYP(plnr)) {
Chris@42: 	  /* Heuristic: if the vector stride is greater than the transform
Chris@42: 	     sz, don't use (prefer to do the vector loop first with a
Chris@42: 	     vrank-geq1 plan). */
Chris@42: 	  const problem_rdft *p = (const problem_rdft *) p_;
Chris@42: 
Chris@42: 	  if (p->vecsz->rnk > 0 &&
Chris@42: 	      X(tensor_min_stride)(p->vecsz) > X(tensor_max_index)(p->sz))
Chris@42: 	       return 0;
Chris@42:      }
Chris@42: 
Chris@42:      return 1;
Chris@42: }
Chris@42: 
Chris@42: static plan *mkplan(const solver *ego_, const problem *p_, planner *plnr)
Chris@42: {
Chris@42:      const S *ego = (const S *) ego_;
Chris@42:      const problem_rdft *p;
Chris@42:      P *pln;
Chris@42:      plan *cld1 = 0, *cld2 = 0;
Chris@42:      tensor *sz1, *sz2, *vecszi, *sz2i;
Chris@42:      int spltrnk;
Chris@42: 
Chris@42:      static const plan_adt padt = {
Chris@42: 	  X(rdft_solve), awake, print, destroy
Chris@42:      };
Chris@42: 
Chris@42:      if (!applicable(ego_, p_, plnr, &spltrnk))
Chris@42:           return (plan *) 0;
Chris@42: 
Chris@42:      p = (const problem_rdft *) p_;
Chris@42:      X(tensor_split)(p->sz, &sz1, spltrnk, &sz2);
Chris@42:      vecszi = X(tensor_copy_inplace)(p->vecsz, INPLACE_OS);
Chris@42:      sz2i = X(tensor_copy_inplace)(sz2, INPLACE_OS);
Chris@42: 
Chris@42:      cld1 = X(mkplan_d)(plnr, 
Chris@42: 			X(mkproblem_rdft_d)(X(tensor_copy)(sz2),
Chris@42: 					    X(tensor_append)(p->vecsz, sz1),
Chris@42: 					    p->I, p->O, p->kind + spltrnk));
Chris@42:      if (!cld1) goto nada;
Chris@42: 
Chris@42:      cld2 = X(mkplan_d)(plnr, 
Chris@42: 			X(mkproblem_rdft_d)(
Chris@42: 			     X(tensor_copy_inplace)(sz1, INPLACE_OS),
Chris@42: 			     X(tensor_append)(vecszi, sz2i),
Chris@42: 			     p->O, p->O, p->kind));
Chris@42:      if (!cld2) goto nada;
Chris@42: 
Chris@42:      pln = MKPLAN_RDFT(P, &padt, apply);
Chris@42: 
Chris@42:      pln->cld1 = cld1;
Chris@42:      pln->cld2 = cld2;
Chris@42: 
Chris@42:      pln->solver = ego;
Chris@42:      X(ops_add)(&cld1->ops, &cld2->ops, &pln->super.super.ops);
Chris@42: 
Chris@42:      X(tensor_destroy4)(sz2, sz1, vecszi, sz2i);
Chris@42: 
Chris@42:      return &(pln->super.super);
Chris@42: 
Chris@42:  nada:
Chris@42:      X(plan_destroy_internal)(cld2);
Chris@42:      X(plan_destroy_internal)(cld1);
Chris@42:      X(tensor_destroy4)(sz2, sz1, vecszi, sz2i);
Chris@42:      return (plan *) 0;
Chris@42: }
Chris@42: 
Chris@42: static solver *mksolver(int spltrnk, const int *buddies, size_t nbuddies)
Chris@42: {
Chris@42:      static const solver_adt sadt = { PROBLEM_RDFT, mkplan, 0 };
Chris@42:      S *slv = MKSOLVER(S, &sadt);
Chris@42:      slv->spltrnk = spltrnk;
Chris@42:      slv->buddies = buddies;
Chris@42:      slv->nbuddies = nbuddies;
Chris@42:      return &(slv->super);
Chris@42: }
Chris@42: 
Chris@42: void X(rdft_rank_geq2_register)(planner *p)
Chris@42: {
Chris@42:      static const int buddies[] = { 1, 0, -2 };
Chris@42:      size_t i;
Chris@42: 
Chris@42:      for (i = 0; i < NELEM(buddies); ++i)
Chris@42:           REGISTER_SOLVER(p, mksolver(buddies[i], buddies, NELEM(buddies)));
Chris@42: 
Chris@42:      /* FIXME: Should we try more buddies?  See also dft/rank-geq2. */
Chris@42: }