/*

 * 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

 *

 */

/* direct RDFT2 R2HC/HC2R solver, if we have a codelet */

#include "rdft/rdft.h"

typedef struct {

     solver super;

     const kr2c_desc *desc;

     kr2c k;

} S;

typedef struct {

     plan_rdft2 super;

     stride rs, cs;

     INT vl;

     INT ivs, ovs;

     kr2c k;

     const S *slv;

     INT ilast;

} P;

static void apply(const plan *ego_, R *r0, R *r1, R *cr, R *ci)

{

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

     ASSERT_ALIGNED_DOUBLE;

     ego->k(r0, r1, cr, ci,

      ego->rs, ego->cs, ego->cs,

      ego->vl, ego->ivs, ego->ovs);

}

static void apply_r2hc(const plan *ego_, R *r0, R *r1, R *cr, R *ci)

{

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

     INT i, vl = ego->vl, ovs = ego->ovs;

     ASSERT_ALIGNED_DOUBLE;

     ego->k(r0, r1, cr, ci,

      ego->rs, ego->cs, ego->cs,

      vl, ego->ivs, ovs);

     for (i = 0; i < vl; ++i, ci += ovs)

    ci[0] = ci[ego->ilast] = 0;

}

static void destroy(plan *ego_)

{

     P *ego = (P *) ego_;

     X(stride_destroy)(ego->rs);

     X(stride_destroy)(ego->cs);

}

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

{

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

     const S *s = ego->slv;

     p->print(p, "(rdft2-%s-direct-%D%v \"%s\")", 

        X(rdft_kind_str)(s->desc->genus->kind), s->desc->n, 

        ego->vl, s->desc->nam);

}

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

{

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

     const kr2c_desc *desc = ego->desc;

     const problem_rdft2 *p = (const problem_rdft2 *) p_;

     INT vl;

     INT ivs, ovs;

     return (

    1

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

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

    && p->sz->dims[0].n == desc->n

    && p->kind == desc->genus->kind

    /* check strides etc */

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

    && (0

        /* can operate out-of-place */

        || p->r0 != p->cr

        /*

         * can compute one transform in-place, no matter

         * what the strides are.

         */

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

        /* can operate in-place as long as strides are the same */

        || X(rdft2_inplace_strides)(p, RNK_MINFTY)

         )

    );

}

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

{

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

     P *pln;

     const problem_rdft2 *p;

     iodim *d;

     int r2hc_kindp;

     static const plan_adt padt = {

    X(rdft2_solve), X(null_awake), print, destroy

     };

     UNUSED(plnr);

     if (!applicable(ego_, p_))

          return (plan *)0;

     p = (const problem_rdft2 *) p_;

     r2hc_kindp = R2HC_KINDP(p->kind);

     A(r2hc_kindp || HC2R_KINDP(p->kind));

     pln = MKPLAN_RDFT2(P, &padt, p->kind == R2HC ? apply_r2hc : apply);

     d = p->sz->dims;

     pln->k = ego->k;

     pln->rs = X(mkstride)(d->n, r2hc_kindp ? d->is : d->os);

     pln->cs = X(mkstride)(d->n, r2hc_kindp ? d->os : d->is);

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

     /* Nyquist freq., if any */

     pln->ilast = (d->n % 2) ? 0 : (d->n/2) * d->os;

     pln->slv = ego;

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

     X(ops_madd2)(pln->vl / ego->desc->genus->vl,

      &ego->desc->ops,

      &pln->super.super.ops);

     if (p->kind == R2HC)

    pln->super.super.ops.other += 2 * pln->vl; /* + 2 stores */

     pln->super.super.could_prune_now_p = 1;

     return &(pln->super.super);

}

/* constructor */

solver *X(mksolver_rdft2_direct)(kr2c k, const kr2c_desc *desc)

{

     static const solver_adt sadt = { PROBLEM_RDFT2, mkplan, 0 };

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

     slv->k = k;

     slv->desc = desc;

     return &(slv->super);

}