/*

 * 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 rank-0 RDFT2 (copy operations, plus setting 0 imag. parts) */

#include "rdft/rdft.h"

#ifdef HAVE_STRING_H

#include <string.h>   /* for memcpy() */

#endif

typedef struct {

     solver super;

} S;

typedef struct {

     plan_rdft super;

     INT vl;

     INT ivs, ovs;

     plan *cldcpy;

} P;

static int applicable(const problem *p_)

{

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

     return (1

       && p->sz->rnk == 0

       && (p->kind == HC2R

     ||

     (1

      && p->kind == R2HC

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

      && ((p->r0 != p->cr) 

          || 

          X(rdft2_inplace_strides)(p, RNK_MINFTY)) ))

    );

}

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;

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

     UNUSED(r1); /* rank-0 has no real odd-index elements */

     for (i = 4; i <= vl; i += 4) {

          R x0, x1, x2, x3;

          x0 = *r0; r0 += ivs;

          x1 = *r0; r0 += ivs;

          x2 = *r0; r0 += ivs;

          x3 = *r0; r0 += ivs;

          *cr = x0; cr += ovs;

    *ci = K(0.0); ci += ovs;

          *cr = x1; cr += ovs;

    *ci = K(0.0); ci += ovs;

          *cr = x2; cr += ovs;

    *ci = K(0.0); ci += ovs;

    *cr = x3; cr += ovs;

    *ci = K(0.0); ci += ovs;

     }

     for (; i < vl + 4; ++i) {

          R x0;

          x0 = *r0; r0 += ivs;

          *cr = x0; cr += ovs;

    *ci = K(0.0); ci += ovs;

     }

}

/* in-place r2hc rank-0: set imaginary parts of output to 0 */

static void apply_r2hc_inplace(const plan *ego_, R *r0, R *r1, R *cr, R *ci)

{

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

     INT i, vl = ego->vl;

     INT ovs = ego->ovs;

     UNUSED(r0); UNUSED(r1); UNUSED(cr);

     for (i = 4; i <= vl; i += 4) {

    *ci = K(0.0); ci += ovs;

    *ci = K(0.0); ci += ovs;

    *ci = K(0.0); ci += ovs;

    *ci = K(0.0); ci += ovs;

     }

     for (; i < vl + 4; ++i) {

    *ci = K(0.0); ci += ovs;

     }

}

/* a rank-0 HC2R rdft2 problem is just a copy from cr to r0,

   so we can use a rank-0 rdft plan */

static void apply_hc2r(const plan *ego_, R *r0, R *r1, R *cr, R *ci)

{

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

     plan_rdft *cldcpy = (plan_rdft *) ego->cldcpy;

     UNUSED(ci);

     UNUSED(r1);

     cldcpy->apply((plan *) cldcpy, cr, r0);

}

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

{

     P *ego = (P *) ego_;

     if (ego->cldcpy)

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

}

static void destroy(plan *ego_)

{

     P *ego = (P *) ego_;

     if (ego->cldcpy)

    X(plan_destroy_internal)(ego->cldcpy);

}

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

{

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

     if (ego->cldcpy)

    p->print(p, "(rdft2-hc2r-rank0%(%p%))", ego->cldcpy);

     else

    p->print(p, "(rdft2-r2hc-rank0%v)", ego->vl);

}

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

{

     const problem_rdft2 *p;

     plan *cldcpy = (plan *) 0;

     P *pln;

     static const plan_adt padt = {

    X(rdft2_solve), awake, print, destroy

     };

     UNUSED(ego_);

     if (!applicable(p_))

          return (plan *) 0;

     p = (const problem_rdft2 *) p_;

     if (p->kind == HC2R) {

    cldcpy = X(mkplan_d)(plnr,

             X(mkproblem_rdft_0_d)(

            X(tensor_copy)(p->vecsz),

            p->cr, p->r0));

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

     }

     pln = MKPLAN_RDFT2(P, &padt, 

      p->kind == R2HC ? 

      (p->r0 == p->cr ? apply_r2hc_inplace : apply_r2hc) 

      : apply_hc2r);

     if (p->kind == R2HC)

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

     pln->cldcpy = cldcpy;

     if (p->kind == R2HC) {

    /* vl loads, 2*vl stores */

    X(ops_other)(3 * pln->vl, &pln->super.super.ops);

     }

     else {

    pln->super.super.ops = cldcpy->ops;

     }

     return &(pln->super.super);

}

static solver *mksolver(void)

{

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

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

     return &(slv->super);

}

void X(rdft2_rank0_register)(planner *p)

{

     REGISTER_SOLVER(p, mksolver());

}