/*

 * 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 RDFT solver, using r2c codelets */

#include "rdft/rdft.h"

typedef struct {

     solver super;

     const kr2c_desc *desc;

     kr2c k;

     int bufferedp;

} S;

typedef struct {

     plan_rdft super;

     stride rs, csr, csi;

     stride brs, bcsr, bcsi;

     INT n, vl, rs0, ivs, ovs, ioffset, bioffset;

     kr2c k;

     const S *slv;

} P;

/*************************************************************

  Nonbuffered code

 *************************************************************/

static void apply_r2hc(const plan *ego_, R *I, R *O)

{

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

     ASSERT_ALIGNED_DOUBLE;

     ego->k(I, I + ego->rs0, O, O + ego->ioffset, 

      ego->rs, ego->csr, ego->csi,

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

}

static void apply_hc2r(const plan *ego_, R *I, R *O)

{

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

     ASSERT_ALIGNED_DOUBLE;

     ego->k(O, O + ego->rs0, I, I + ego->ioffset, 

      ego->rs, ego->csr, ego->csi,

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

}

/*************************************************************

  Buffered code

 *************************************************************/

/* should not be 2^k to avoid associativity conflicts */

static INT compute_batchsize(INT radix)

{

     /* round up to multiple of 4 */

     radix += 3;

     radix &= -4;

     return (radix + 2);

}

static void dobatch_r2hc(const P *ego, R *I, R *O, R *buf, INT batchsz)

{

     X(cpy2d_ci)(I, buf,

     ego->n, ego->rs0, WS(ego->bcsr /* hack */, 1),

     batchsz, ego->ivs, 1, 1);

     if (IABS(WS(ego->csr, 1)) < IABS(ego->ovs)) {

    /* transform directly to output */

    ego->k(buf, buf + WS(ego->bcsr /* hack */, 1), 

     O, O + ego->ioffset, 

     ego->brs, ego->csr, ego->csi,

     batchsz, 1, ego->ovs);

     } else {

    /* transform to buffer and copy back */

    ego->k(buf, buf + WS(ego->bcsr /* hack */, 1), 

     buf, buf + ego->bioffset, 

     ego->brs, ego->bcsr, ego->bcsi,

     batchsz, 1, 1);

    X(cpy2d_co)(buf, O,

          ego->n, WS(ego->bcsr, 1), WS(ego->csr, 1),  

          batchsz, 1, ego->ovs, 1);

     }

}

static void dobatch_hc2r(const P *ego, R *I, R *O, R *buf, INT batchsz)

{

     if (IABS(WS(ego->csr, 1)) < IABS(ego->ivs)) {

    /* transform directly from input */

    ego->k(buf, buf + WS(ego->bcsr /* hack */, 1),

     I, I + ego->ioffset, 

     ego->brs, ego->csr, ego->csi,

     batchsz, ego->ivs, 1);

     } else {

    /* copy into buffer and transform in place */

    X(cpy2d_ci)(I, buf,

          ego->n, WS(ego->csr, 1), WS(ego->bcsr, 1),

          batchsz, ego->ivs, 1, 1);

    ego->k(buf, buf + WS(ego->bcsr /* hack */, 1),

     buf, buf + ego->bioffset, 

     ego->brs, ego->bcsr, ego->bcsi,

     batchsz, 1, 1);

     }

     X(cpy2d_co)(buf, O,

     ego->n, WS(ego->bcsr /* hack */, 1), ego->rs0,

     batchsz, 1, ego->ovs, 1);

}

static void iterate(const P *ego, R *I, R *O,

        void (*dobatch)(const P *ego, R *I, R *O, 

            R *buf, INT batchsz))

{

     R *buf;

     INT vl = ego->vl;

     INT n = ego->n;

     INT i;

     INT batchsz = compute_batchsize(n);

     size_t bufsz = n * batchsz * sizeof(R);

     BUF_ALLOC(R *, buf, bufsz);

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

    dobatch(ego, I, O, buf, batchsz);

    I += batchsz * ego->ivs;

    O += batchsz * ego->ovs;

     }

     dobatch(ego, I, O, buf, vl - i);

     BUF_FREE(buf, bufsz);

}

static void apply_buf_r2hc(const plan *ego_, R *I, R *O)

{

     iterate((const P *) ego_, I, O, dobatch_r2hc);

}

static void apply_buf_hc2r(const plan *ego_, R *I, R *O)

{

     iterate((const P *) ego_, I, O, dobatch_hc2r);

}

static void destroy(plan *ego_)

{

     P *ego = (P *) ego_;

     X(stride_destroy)(ego->rs);

     X(stride_destroy)(ego->csr);

     X(stride_destroy)(ego->csi);

     X(stride_destroy)(ego->brs);

     X(stride_destroy)(ego->bcsr);

     X(stride_destroy)(ego->bcsi);

}

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

{

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

     const S *s = ego->slv;

     if (ego->slv->bufferedp)

    p->print(p, "(rdft-%s-directbuf/%D-r2c-%D%v \"%s\")", 

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

       /* hack */ WS(ego->bcsr, 1), ego->n, 

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

     else 

    p->print(p, "(rdft-%s-direct-r2c-%D%v \"%s\")", 

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

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

}

static INT ioffset(rdft_kind kind, INT sz, INT s)

{

     return(s * ((kind == R2HC || kind == HC2R) ? sz : (sz - 1)));

}

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

{

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

     const kr2c_desc *desc = ego->desc;

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

     INT vl, ivs, ovs;

     return (

    1

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

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

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

    && p->kind[0] == desc->genus->kind

    /* check strides etc */

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

    && (0

        /* can operate out-of-place */

        || p->I != p->O

        /* computing one transform */

        || vl == 1

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

        || X(tensor_inplace_strides2)(p->sz, p->vecsz)

         )

    );

}

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

{

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

     const kr2c_desc *desc = ego->desc;

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

     INT vl, ivs, ovs, batchsz;

     return (

    1

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

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

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

    && p->kind[0] == desc->genus->kind

    /* check strides etc */

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

    && (batchsz = compute_batchsize(desc->n), 1)

    && (0

        /* can operate out-of-place */

        || p->I != p->O

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

        || X(tensor_inplace_strides2)(p->sz, p->vecsz)

        /* can do it if the problem fits in the buffer, no matter

     what the strides are */

        || vl <= batchsz

         )

    );

}

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

{

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

     P *pln;

     const problem_rdft *p;

     iodim *d;

     INT rs, cs, b, n;

     static const plan_adt padt = {

    X(rdft_solve), X(null_awake), print, destroy

     };

     UNUSED(plnr);

     if (ego->bufferedp) {

    if (!applicable_buf(ego_, p_))

         return (plan *)0;

     } else {

    if (!applicable(ego_, p_))

         return (plan *)0;

     }

     p = (const problem_rdft *) p_;

     if (R2HC_KINDP(p->kind[0])) {

    rs = p->sz->dims[0].is; cs = p->sz->dims[0].os;

    pln = MKPLAN_RDFT(P, &padt, 

          ego->bufferedp ? apply_buf_r2hc : apply_r2hc);

     } else {

    rs = p->sz->dims[0].os; cs = p->sz->dims[0].is;

    pln = MKPLAN_RDFT(P, &padt, 

          ego->bufferedp ? apply_buf_hc2r : apply_hc2r);

     }

     d = p->sz->dims;

     n = d[0].n;

     pln->k = ego->k;

     pln->n = n;

     pln->rs0 = rs;

     pln->rs = X(mkstride)(n, 2 * rs);

     pln->csr = X(mkstride)(n, cs);

     pln->csi = X(mkstride)(n, -cs);

     pln->ioffset = ioffset(p->kind[0], n, cs);

     b = compute_batchsize(n);

     pln->brs = X(mkstride)(n, 2 * b);

     pln->bcsr = X(mkstride)(n, b);

     pln->bcsi = X(mkstride)(n, -b);

     pln->bioffset = ioffset(p->kind[0], n, b);

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

     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 (ego->bufferedp) 

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

     pln->super.super.could_prune_now_p = !ego->bufferedp;

     return &(pln->super.super);

}

/* constructor */

static solver *mksolver(kr2c k, const kr2c_desc *desc, int bufferedp)

{

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

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

     slv->k = k;

     slv->desc = desc;

     slv->bufferedp = bufferedp;

     return &(slv->super);

}

solver *X(mksolver_rdft_r2c_direct)(kr2c k, const kr2c_desc *desc)

{

     return mksolver(k, desc, 0);

}

solver *X(mksolver_rdft_r2c_directbuf)(kr2c k, const kr2c_desc *desc)

{

     return mksolver(k, desc, 1);

}