/*

 * 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

 *

 */

/* Plans for handling vector transform loops.  These are *just* the

   loops, and rely on child plans for the actual DFTs.

   They form a wrapper around solvers that don't have apply functions

   for non-null vectors.

   vrank-geq1 plans also recursively handle the case of multi-dimensional

   vectors, obviating the need for most solvers to deal with this.  We

   can also play games here, such as reordering the vector loops.

   Each vrank-geq1 plan reduces the vector rank by 1, picking out a

   dimension determined by the vecloop_dim field of the solver. */

#include "dft/dft.h"

typedef struct {

     solver super;

     int vecloop_dim;

     const int *buddies;

     size_t nbuddies;

} S;

typedef struct {

     plan_dft super;

     plan *cld;

     INT vl;

     INT ivs, ovs;

     const S *solver;

} P;

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

{

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

     INT i, vl = ego->vl;

     INT ivs = ego->ivs, ovs = ego->ovs;

     dftapply cldapply = ((plan_dft *) ego->cld)->apply;

     for (i = 0; i < vl; ++i) {

          cldapply(ego->cld,

                   ri + i * ivs, ii + i * ivs, ro + i * ovs, io + i * ovs);

     }

}

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

{

     P *ego = (P *) ego_;

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

}

static void destroy(plan *ego_)

{

     P *ego = (P *) ego_;

     X(plan_destroy_internal)(ego->cld);

}

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

{

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

     const S *s = ego->solver;

     p->print(p, "(dft-vrank>=1-x%D/%d%(%p%))",

        ego->vl, s->vecloop_dim, ego->cld);

}

static int pickdim(const S *ego, const tensor *vecsz, int oop, int *dp)

{

     return X(pickdim)(ego->vecloop_dim, ego->buddies, ego->nbuddies,

           vecsz, oop, dp);

}

static int applicable0(const solver *ego_, const problem *p_, int *dp)

{

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

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

     return (1

       && FINITE_RNK(p->vecsz->rnk)

       && p->vecsz->rnk > 0

       /* do not bother looping over rank-0 problems,

    since they are handled via rdft */

       && p->sz->rnk > 0

       && pickdim(ego, p->vecsz, p->ri != p->ro, dp)

    );

}

static int applicable(const solver *ego_, const problem *p_, 

          const planner *plnr, int *dp)

{

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

     const problem_dft *p;

     if (!applicable0(ego_, p_, dp)) return 0;

     /* fftw2 behavior */

     if (NO_VRANK_SPLITSP(plnr) && (ego->vecloop_dim != ego->buddies[0]))

    return 0;

     p = (const problem_dft *) p_;

     if (NO_UGLYP(plnr)) {

    /* Heuristic: if the transform is multi-dimensional, and the

       vector stride is less than the transform size, then we

       probably want to use a rank>=2 plan first in order to combine

       this vector with the transform-dimension vectors. */

    {

         iodim *d = p->vecsz->dims + *dp;

         if (1

       && p->sz->rnk > 1 

       && X(imin)(X(iabs)(d->is), X(iabs)(d->os)) 

       < X(tensor_max_index)(p->sz)

        )

        return 0;

    }

    if (NO_NONTHREADEDP(plnr)) return 0; /* prefer threaded version */

     }

     return 1;

}

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

{

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

     const problem_dft *p;

     P *pln;

     plan *cld;

     int vdim;

     iodim *d;

     static const plan_adt padt = {

    X(dft_solve), awake, print, destroy

     };

     if (!applicable(ego_, p_, plnr, &vdim))

          return (plan *) 0;

     p = (const problem_dft *) p_;

     d = p->vecsz->dims + vdim;

     A(d->n > 1);

     cld = X(mkplan_d)(plnr,

           X(mkproblem_dft_d)(

          X(tensor_copy)(p->sz),

          X(tensor_copy_except)(p->vecsz, vdim),

          TAINT(p->ri, d->is), TAINT(p->ii, d->is),

          TAINT(p->ro, d->os), TAINT(p->io, d->os)));

     if (!cld) return (plan *) 0;

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

     pln->cld = cld;

     pln->vl = d->n;

     pln->ivs = d->is;

     pln->ovs = d->os;

     pln->solver = ego;

     X(ops_zero)(&pln->super.super.ops);

     pln->super.super.ops.other = 3.14159; /* magic to prefer codelet loops */

     X(ops_madd2)(pln->vl, &cld->ops, &pln->super.super.ops);

     if (p->sz->rnk != 1 || (p->sz->dims[0].n > 64))

    pln->super.super.pcost = pln->vl * cld->pcost;

     return &(pln->super.super);

}

static solver *mksolver(int vecloop_dim, const int *buddies, size_t nbuddies)

{

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

     S *slv = MKSOLVER(S, &sadt);

     slv->vecloop_dim = vecloop_dim;

     slv->buddies = buddies;

     slv->nbuddies = nbuddies;

     return &(slv->super);

}

void X(dft_vrank_geq1_register)(planner *p)

{

     /* FIXME: Should we try other vecloop_dim values? */

     static const int buddies[] = { 1, -1 };

     size_t i;

     for (i = 0; i < NELEM(buddies); ++i)

          REGISTER_SOLVER(p, mksolver(buddies[i], buddies, NELEM(buddies)));

}