/*

 * 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 "dft/ct.h"

ct_solver *(*X(mksolver_ct_hook))(size_t, INT, int, 

          ct_mkinferior, ct_force_vrecursion) = 0;

typedef struct {

     plan_dft super;

     plan *cld;

     plan *cldw;

     INT r;

} P;

static void apply_dit(const plan *ego_, R *ri, R *ii, R *ro, R *io)

{

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

     plan_dft *cld;

     plan_dftw *cldw;

     cld = (plan_dft *) ego->cld;

     cld->apply(ego->cld, ri, ii, ro, io);

     cldw = (plan_dftw *) ego->cldw;

     cldw->apply(ego->cldw, ro, io);

}

static void apply_dif(const plan *ego_, R *ri, R *ii, R *ro, R *io)

{

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

     plan_dft *cld;

     plan_dftw *cldw;

     cldw = (plan_dftw *) ego->cldw;

     cldw->apply(ego->cldw, ri, ii);

     cld = (plan_dft *) ego->cld;

     cld->apply(ego->cld, ri, ii, ro, io);

}

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, "(dft-ct-%s/%D%(%p%)%(%p%))",

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

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

}

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

{

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

     INT r;

     return (1

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

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

       /* DIF destroys the input and we don't like it */

       && (ego->dec == DECDIT ||

     p->ri == p->ro ||

     !NO_DESTROY_INPUTP(plnr))

       && ((r = X(choose_radix)(ego->r, p->sz->dims[0].n)) > 1)

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

}

int X(ct_applicable)(const ct_solver *ego, const problem *p_, planner *plnr)

{

     const problem_dft *p;

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

          return 0;

     p = (const problem_dft *) p_;

     return (0

       || ego->dec == DECDIF+TRANSPOSE

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

       || !NO_VRECURSEP(plnr)

       || (ego->force_vrecursionp && ego->force_vrecursionp(ego, p))

    );

}

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

{

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

     const problem_dft *p;

     P *pln = 0;

     plan *cld = 0, *cldw = 0;

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

     iodim *d;

     static const plan_adt padt = {

    X(dft_solve), awake, print, destroy

     };

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

          return (plan *) 0;

     p = (const problem_dft *) 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 (ego->dec) {

   case DECDIT:

   {

        cldw = ego->mkcldw(ego,

         r, m * d[0].os, m * d[0].os,

         m, d[0].os,

         v, ovs, ovs,

         0, m,

         p->ro, p->io, plnr);

        if (!cldw) goto nada;

        cld = X(mkplan_d)(plnr,

        X(mkproblem_dft_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->ri, p->ii, p->ro, p->io)

       );

        if (!cld) goto nada;

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

        break;

   }

   case DECDIF:

   case DECDIF+TRANSPOSE:

   {

        INT cors, covs; /* cldw ors, ovs */

        if (ego->dec == DECDIF+TRANSPOSE) {

       cors = ivs;

       covs = m * d[0].is;

       /* ensure that we generate well-formed dftw subproblems */

       /* FIXME: too conservative */

       if (!(1

       && r == v

       && d[0].is == r * cors))

      goto nada;

       /* FIXME: allow in-place only for now, like in

          fftw-3.[01] */

       if (!(1

       && p->ri == p->ro

       && d[0].is == r * d[0].os

       && cors == d[0].os

       && covs == ovs

          ))

      goto nada;

        } else {

       cors = m * d[0].is;

       covs = ivs;

        }

        cldw = ego->mkcldw(ego,

         r, m * d[0].is, cors,

         m, d[0].is,

         v, ivs, covs,

         0, m,

         p->ri, p->ii, plnr);

        if (!cldw) goto nada;

        cld = X(mkplan_d)(plnr,

        X(mkproblem_dft_d)(

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

             X(mktensor_2d)(r, cors, d[0].os,

                v, covs, ovs),

             p->ri, p->ii, p->ro, p->io)

       );

        if (!cld) goto nada;

        pln = MKPLAN_DFT(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;

}

ct_solver *X(mksolver_ct)(size_t size, INT r, int dec, 

        ct_mkinferior mkcldw,

        ct_force_vrecursion force_vrecursionp)

{

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

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

     slv->r = r;

     slv->dec = dec;

     slv->mkcldw = mkcldw;

     slv->force_vrecursionp = force_vrecursionp;

     return slv;

}

plan *X(mkplan_dftw)(size_t size, const plan_adt *adt, dftwapply apply)

{

     plan_dftw *ego;

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

     ego->apply = apply;

     return &(ego->super);

}