cannam@127: /*
cannam@127:  * Copyright (c) 2003, 2007-14 Matteo Frigo
cannam@127:  * Copyright (c) 2003, 2007-14 Massachusetts Institute of Technology
cannam@127:  *
cannam@127:  * This program is free software; you can redistribute it and/or modify
cannam@127:  * it under the terms of the GNU General Public License as published by
cannam@127:  * the Free Software Foundation; either version 2 of the License, or
cannam@127:  * (at your option) any later version.
cannam@127:  *
cannam@127:  * This program is distributed in the hope that it will be useful,
cannam@127:  * but WITHOUT ANY WARRANTY; without even the implied warranty of
cannam@127:  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
cannam@127:  * GNU General Public License for more details.
cannam@127:  *
cannam@127:  * You should have received a copy of the GNU General Public License
cannam@127:  * along with this program; if not, write to the Free Software
cannam@127:  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301  USA
cannam@127:  *
cannam@127:  */
cannam@127: 
cannam@127: 
cannam@127: /* Compute the complex DFT by combining R2HC RDFTs on the real
cannam@127:    and imaginary parts.   This could be useful for people just wanting
cannam@127:    to link to the real codelets and not the complex ones.  It could
cannam@127:    also even be faster than the complex algorithms for split (as opposed
cannam@127:    to interleaved) real/imag complex data. */
cannam@127: 
cannam@127: #include "rdft.h"
cannam@127: #include "dft.h"
cannam@127: 
cannam@127: typedef struct {
cannam@127:      solver super;
cannam@127: } S;
cannam@127: 
cannam@127: typedef struct {
cannam@127:      plan_dft super;
cannam@127:      plan *cld;
cannam@127:      INT ishift, oshift;
cannam@127:      INT os;
cannam@127:      INT n;
cannam@127: } P;
cannam@127: 
cannam@127: static void apply(const plan *ego_, R *ri, R *ii, R *ro, R *io)
cannam@127: {
cannam@127:      const P *ego = (const P *) ego_;
cannam@127:      INT n;
cannam@127: 
cannam@127:      UNUSED(ii);
cannam@127: 
cannam@127:      { /* transform vector of real & imag parts: */
cannam@127: 	  plan_rdft *cld = (plan_rdft *) ego->cld;
cannam@127: 	  cld->apply((plan *) cld, ri + ego->ishift, ro + ego->oshift);
cannam@127:      }
cannam@127: 
cannam@127:      n = ego->n;
cannam@127:      if (n > 1) {
cannam@127: 	  INT i, os = ego->os;
cannam@127: 	  for (i = 1; i < (n + 1)/2; ++i) {
cannam@127: 	       E rop, iop, iom, rom;
cannam@127: 	       rop = ro[os * i];
cannam@127: 	       iop = io[os * i];
cannam@127: 	       rom = ro[os * (n - i)];
cannam@127: 	       iom = io[os * (n - i)];
cannam@127: 	       ro[os * i] = rop - iom;
cannam@127: 	       io[os * i] = iop + rom;
cannam@127: 	       ro[os * (n - i)] = rop + iom;
cannam@127: 	       io[os * (n - i)] = iop - rom;
cannam@127: 	  }
cannam@127:      }
cannam@127: }
cannam@127: 
cannam@127: static void awake(plan *ego_, enum wakefulness wakefulness)
cannam@127: {
cannam@127:      P *ego = (P *) ego_;
cannam@127:      X(plan_awake)(ego->cld, wakefulness);
cannam@127: }
cannam@127: 
cannam@127: static void destroy(plan *ego_)
cannam@127: {
cannam@127:      P *ego = (P *) ego_;
cannam@127:      X(plan_destroy_internal)(ego->cld);
cannam@127: }
cannam@127: 
cannam@127: static void print(const plan *ego_, printer *p)
cannam@127: {
cannam@127:      const P *ego = (const P *) ego_;
cannam@127:      p->print(p, "(dft-r2hc-%D%(%p%))", ego->n, ego->cld);
cannam@127: }
cannam@127: 
cannam@127: 
cannam@127: static int applicable0(const problem *p_)
cannam@127: {
cannam@127:      const problem_dft *p = (const problem_dft *) p_;
cannam@127:      return ((p->sz->rnk == 1 && p->vecsz->rnk == 0)
cannam@127: 	     || (p->sz->rnk == 0 && FINITE_RNK(p->vecsz->rnk))
cannam@127: 	  );
cannam@127: }
cannam@127: 
cannam@127: static int splitp(R *r, R *i, INT n, INT s)
cannam@127: {
cannam@127:      return ((r > i ? (r - i) : (i - r)) >= n * (s > 0 ? s : 0-s));
cannam@127: }
cannam@127: 
cannam@127: static int applicable(const problem *p_, const planner *plnr)
cannam@127: {
cannam@127:      if (!applicable0(p_)) return 0;
cannam@127: 
cannam@127:      {
cannam@127: 	  const problem_dft *p = (const problem_dft *) p_;
cannam@127: 
cannam@127: 	  /* rank-0 problems are always OK */
cannam@127: 	  if (p->sz->rnk == 0) return 1;
cannam@127: 
cannam@127: 	  /* this solver is ok for split arrays */
cannam@127: 	  if (p->sz->rnk == 1 &&
cannam@127: 	      splitp(p->ri, p->ii, p->sz->dims[0].n, p->sz->dims[0].is) &&
cannam@127: 	      splitp(p->ro, p->io, p->sz->dims[0].n, p->sz->dims[0].os))
cannam@127: 	       return 1;
cannam@127: 
cannam@127: 	  return !(NO_DFT_R2HCP(plnr));
cannam@127:      }
cannam@127: }
cannam@127: 
cannam@127: static plan *mkplan(const solver *ego_, const problem *p_, planner *plnr)
cannam@127: {
cannam@127:      P *pln;
cannam@127:      const problem_dft *p;
cannam@127:      plan *cld;
cannam@127:      INT ishift = 0, oshift = 0;
cannam@127: 
cannam@127:      static const plan_adt padt = {
cannam@127: 	  X(dft_solve), awake, print, destroy
cannam@127:      };
cannam@127: 
cannam@127:      UNUSED(ego_);
cannam@127:      if (!applicable(p_, plnr))
cannam@127:           return (plan *)0;
cannam@127: 
cannam@127:      p = (const problem_dft *) p_;
cannam@127: 
cannam@127:      {
cannam@127: 	  tensor *ri_vec = X(mktensor_1d)(2, p->ii - p->ri, p->io - p->ro);
cannam@127: 	  tensor *cld_vec = X(tensor_append)(ri_vec, p->vecsz);
cannam@127: 	  int i;
cannam@127: 	  for (i = 0; i < cld_vec->rnk; ++i) { /* make all istrides > 0 */
cannam@127: 	       if (cld_vec->dims[i].is < 0) {
cannam@127: 		    INT nm1 = cld_vec->dims[i].n - 1;
cannam@127: 		    ishift -= nm1 * (cld_vec->dims[i].is *= -1);
cannam@127: 		    oshift -= nm1 * (cld_vec->dims[i].os *= -1);
cannam@127: 	       }
cannam@127: 	  }
cannam@127: 	  cld = X(mkplan_d)(plnr, 
cannam@127: 			    X(mkproblem_rdft_1)(p->sz, cld_vec, 
cannam@127: 						p->ri + ishift, 
cannam@127: 						p->ro + oshift, R2HC));
cannam@127: 	  X(tensor_destroy2)(ri_vec, cld_vec);
cannam@127:      }
cannam@127:      if (!cld) return (plan *)0;
cannam@127: 
cannam@127:      pln = MKPLAN_DFT(P, &padt, apply);
cannam@127: 
cannam@127:      if (p->sz->rnk == 0) {
cannam@127: 	  pln->n = 1;
cannam@127: 	  pln->os = 0;
cannam@127:      }
cannam@127:      else {
cannam@127: 	  pln->n = p->sz->dims[0].n;
cannam@127: 	  pln->os = p->sz->dims[0].os;
cannam@127:      }
cannam@127:      pln->ishift = ishift;
cannam@127:      pln->oshift = oshift;
cannam@127: 
cannam@127:      pln->cld = cld;
cannam@127:      
cannam@127:      pln->super.super.ops = cld->ops;
cannam@127:      pln->super.super.ops.other += 8 * ((pln->n - 1)/2);
cannam@127:      pln->super.super.ops.add += 4 * ((pln->n - 1)/2);
cannam@127:      pln->super.super.ops.other += 1; /* estimator hack for nop plans */
cannam@127: 
cannam@127:      return &(pln->super.super);
cannam@127: }
cannam@127: 
cannam@127: /* constructor */
cannam@127: static solver *mksolver(void)
cannam@127: {
cannam@127:      static const solver_adt sadt = { PROBLEM_DFT, mkplan, 0 };
cannam@127:      S *slv = MKSOLVER(S, &sadt);
cannam@127:      return &(slv->super);
cannam@127: }
cannam@127: 
cannam@127: void X(dft_r2hc_register)(planner *p)
cannam@127: {
cannam@127:      REGISTER_SOLVER(p, mksolver());
cannam@127: }