/*

 * Copyright (c) 2003, 2007-14 Matteo Frigo

 * Copyright (c) 2003, 2007-14 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., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301  USA

 *

 */

#include "rdft/hc2hc.h"

hc2hc_solver *(*X(mksolver_hc2hc_hook))(size_t, INT, hc2hc_mkinferior) = 0;

typedef struct {

     plan_rdft super;

     plan *cld;

     plan *cldw;

     INT r;

} P;

static void apply_dit(const plan *ego_, R *I, R *O)

{

     const P *ego = (const P *) ego_;

     plan_rdft *cld;

     plan_hc2hc *cldw;

     cld = (plan_rdft *) ego->cld;

     cld->apply(ego->cld, I, O);

     cldw = (plan_hc2hc *) ego->cldw;

     cldw->apply(ego->cldw, O);

}

static void apply_dif(const plan *ego_, R *I, R *O)

{

     const P *ego = (const P *) ego_;

     plan_rdft *cld;

     plan_hc2hc *cldw;

     cldw = (plan_hc2hc *) ego->cldw;

     cldw->apply(ego->cldw, I);

     cld = (plan_rdft *) ego->cld;

     cld->apply(ego->cld, I, O);

}

static void awake(plan *ego_, enum wakefulness wakefulness)

{

     P *ego = (P *) ego_;

     X(plan_awake)(ego->cld, wakefulness);

     X(plan_awake)(ego->cldw, wakefulness);

}

static void destroy(plan *ego_)

{

     P *ego = (P *) ego_;

     X(plan_destroy_internal)(ego->cldw);

     X(plan_destroy_internal)(ego->cld);

}

static void print(const plan *ego_, printer *p)

{

     const P *ego = (const P *) ego_;

     p->print(p, "(rdft-ct-%s/%D%(%p%)%(%p%))",

        ego->super.apply == apply_dit ? "dit" : "dif",

        ego->r, ego->cldw, ego->cld);

}

static int applicable0(const hc2hc_solver *ego, const problem *p_, planner *plnr)

{

     const problem_rdft *p = (const problem_rdft *) p_;

     INT r;

     return (1

       && p->sz->rnk == 1

       && p->vecsz->rnk <= 1 

       && (/* either the problem is R2HC, which is solved by DIT */

      (p->kind[0] == R2HC)

      ||

      /* or the problem is HC2R, in which case it is solved

         by DIF, which destroys the input */

      (p->kind[0] == HC2R && 

       (p->I == p->O || !NO_DESTROY_INPUTP(plnr))))

       && ((r = X(choose_radix)(ego->r, p->sz->dims[0].n)) > 0)

       && p->sz->dims[0].n > r);

}

int X(hc2hc_applicable)(const hc2hc_solver *ego, const problem *p_, planner *plnr)

{

     const problem_rdft *p;

     if (!applicable0(ego, p_, plnr))

          return 0;

     p = (const problem_rdft *) p_;

     return (0

       || p->vecsz->rnk == 0

       || !NO_VRECURSEP(plnr)

    );

}

static plan *mkplan(const solver *ego_, const problem *p_, planner *plnr)

{

     const hc2hc_solver *ego = (const hc2hc_solver *) ego_;

     const problem_rdft *p;

     P *pln = 0;

     plan *cld = 0, *cldw = 0;

     INT n, r, m, v, ivs, ovs;

     iodim *d;

     static const plan_adt padt = {

    X(rdft_solve), awake, print, destroy

     };

     if (NO_NONTHREADEDP(plnr) || !X(hc2hc_applicable)(ego, p_, plnr))

          return (plan *) 0;

     p = (const problem_rdft *) p_;

     d = p->sz->dims;

     n = d[0].n;

     r = X(choose_radix)(ego->r, n);

     m = n / r;

     X(tensor_tornk1)(p->vecsz, &v, &ivs, &ovs);

     switch (p->kind[0]) {

   case R2HC:

        cldw = ego->mkcldw(ego, 

         R2HC, r, m, d[0].os, v, ovs, 0, (m+2)/2, 

         p->O, plnr);

        if (!cldw) goto nada;

        cld = X(mkplan_d)(plnr, 

        X(mkproblem_rdft_d)(

             X(mktensor_1d)(m, r * d[0].is, d[0].os),

             X(mktensor_2d)(r, d[0].is, m * d[0].os,

                v, ivs, ovs),

             p->I, p->O, p->kind)

       );

        if (!cld) goto nada;

        pln = MKPLAN_RDFT(P, &padt, apply_dit);

        break;

   case HC2R:

        cldw = ego->mkcldw(ego,

         HC2R, r, m, d[0].is, v, ivs, 0, (m+2)/2, 

         p->I, plnr);

        if (!cldw) goto nada;

        cld = X(mkplan_d)(plnr, 

        X(mkproblem_rdft_d)(

             X(mktensor_1d)(m, d[0].is, r * d[0].os),

             X(mktensor_2d)(r, m * d[0].is, d[0].os,

                v, ivs, ovs),

             p->I, p->O, p->kind)

       );

        if (!cld) goto nada;

        pln = MKPLAN_RDFT(P, &padt, apply_dif);

        break;

   default: 

        A(0);

     }

     pln->cld = cld;

     pln->cldw = cldw;

     pln->r = r;

     X(ops_add)(&cld->ops, &cldw->ops, &pln->super.super.ops);

     /* inherit could_prune_now_p attribute from cldw */

     pln->super.super.could_prune_now_p = cldw->could_prune_now_p;

     return &(pln->super.super);

 nada:

     X(plan_destroy_internal)(cldw);

     X(plan_destroy_internal)(cld);

     return (plan *) 0;

}

hc2hc_solver *X(mksolver_hc2hc)(size_t size, INT r, hc2hc_mkinferior mkcldw)

{

     static const solver_adt sadt = { PROBLEM_RDFT, mkplan, 0 };

     hc2hc_solver *slv = (hc2hc_solver *)X(mksolver)(size, &sadt);

     slv->r = r;

     slv->mkcldw = mkcldw;

     return slv;

}

plan *X(mkplan_hc2hc)(size_t size, const plan_adt *adt, hc2hcapply apply)

{

     plan_hc2hc *ego;

     ego = (plan_hc2hc *) X(mkplan)(size, adt);

     ego->apply = apply;

     return &(ego->super);

}