/*

 * 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"

typedef struct {

     ct_solver super;

     const ct_desc *desc;

     int bufferedp;

     kdftw k;

} S;

typedef struct {

     plan_dftw super;

     kdftw k;

     INT r;

     stride rs;

     INT m, ms, v, vs, mb, me, extra_iter;

     stride brs;

     twid *td;

     const S *slv;

} P;

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

  Nonbuffered code

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

static void apply(const plan *ego_, R *rio, R *iio)

{

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

     INT i;

     ASSERT_ALIGNED_DOUBLE;

     for (i = 0; i < ego->v; ++i, rio += ego->vs, iio += ego->vs) {

    INT  mb = ego->mb, ms = ego->ms;

    ego->k(rio + mb*ms, iio + mb*ms, ego->td->W, 

     ego->rs, mb, ego->me, ms);

     }

}

static void apply_extra_iter(const plan *ego_, R *rio, R *iio)

{

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

     INT i, v = ego->v, vs = ego->vs;

     INT mb = ego->mb, me = ego->me, mm = me - 1, ms = ego->ms;

     ASSERT_ALIGNED_DOUBLE;

     for (i = 0; i < v; ++i, rio += vs, iio += vs) {

    ego->k(rio + mb*ms, iio + mb*ms, ego->td->W, 

     ego->rs, mb, mm, ms);

    ego->k(rio + mm*ms, iio + mm*ms, ego->td->W, 

     ego->rs, mm, mm+2, 0);

     }

}

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

  Buffered code

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

static void dobatch(const P *ego, R *rA, R *iA, INT mb, INT me, R *buf)

{

     INT brs = WS(ego->brs, 1);

     INT rs = WS(ego->rs, 1);

     INT ms = ego->ms;

     X(cpy2d_pair_ci)(rA + mb*ms, iA + mb*ms, buf, buf + 1,

          ego->r, rs, brs,

          me - mb, ms, 2);

     ego->k(buf, buf + 1, ego->td->W, ego->brs, mb, me, 2);

     X(cpy2d_pair_co)(buf, buf + 1, rA + mb*ms, iA + mb*ms,

          ego->r, brs, rs,

          me - mb, 2, ms);

}

/* must be even for SIMD alignment; 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 apply_buf(const plan *ego_, R *rio, R *iio)

{

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

     INT i, j, v = ego->v, r = ego->r;

     INT batchsz = compute_batchsize(r);

     R *buf;

     INT mb = ego->mb, me = ego->me;

     size_t bufsz = r * batchsz * 2 * sizeof(R);

     BUF_ALLOC(R *, buf, bufsz);

     for (i = 0; i < v; ++i, rio += ego->vs, iio += ego->vs) {

    for (j = mb; j + batchsz < me; j += batchsz) 

         dobatch(ego, rio, iio, j, j + batchsz, buf);

    dobatch(ego, rio, iio, j, me, buf);

     }

     BUF_FREE(buf, bufsz);

}

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

  common code

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

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

{

     P *ego = (P *) ego_;

     X(twiddle_awake)(wakefulness, &ego->td, ego->slv->desc->tw,

          ego->r * ego->m, ego->r, ego->m + ego->extra_iter);

}

static void destroy(plan *ego_)

{

     P *ego = (P *) ego_;

     X(stride_destroy)(ego->brs);

     X(stride_destroy)(ego->rs);

}

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

{

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

     const S *slv = ego->slv;

     const ct_desc *e = slv->desc;

     if (slv->bufferedp)

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

       compute_batchsize(ego->r), ego->r,

       X(twiddle_length)(ego->r, e->tw), ego->v, e->nam);

     else

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

       ego->r, X(twiddle_length)(ego->r, e->tw), ego->v, e->nam);

}

static int applicable0(const S *ego,

           INT r, INT irs, INT ors,

           INT m, INT ms,

           INT v, INT ivs, INT ovs,

           INT mb, INT me,

           R *rio, R *iio,

           const planner *plnr, INT *extra_iter)

{

     const ct_desc *e = ego->desc;

     UNUSED(v);

     return (

    1

    && r == e->radix

    && irs == ors /* in-place along R */

    && ivs == ovs /* in-place along V */

    /* check for alignment/vector length restrictions */

    && ((*extra_iter = 0,

         e->genus->okp(e, rio, iio, irs, ivs, m, mb, me, ms, plnr))

        ||

        (*extra_iter = 1,

         (1

    /* FIXME: require full array, otherwise some threads

       may be extra_iter and other threads won't be.

       Generating the proper twiddle factors is a pain in

       this case */

    && mb == 0 && me == m

    && e->genus->okp(e, rio, iio, irs, ivs,

         m, mb, me - 1, ms, plnr)

    && e->genus->okp(e, rio, iio, irs, ivs,

         m, me - 1, me + 1, ms, plnr))))

    && (e->genus->okp(e, rio + ivs, iio + ivs, irs, ivs,

          m, mb, me - *extra_iter, ms, plnr))

    );

}

static int applicable0_buf(const S *ego,

         INT r, INT irs, INT ors,

         INT m, INT ms,

         INT v, INT ivs, INT ovs,

         INT mb, INT me,

         R *rio, R *iio,

         const planner *plnr)

{

     const ct_desc *e = ego->desc;

     INT batchsz;

     UNUSED(v); UNUSED(ms); UNUSED(rio); UNUSED(iio);

     return (

    1

    && r == e->radix

    && irs == ors /* in-place along R */

    && ivs == ovs /* in-place along V */

    /* check for alignment/vector length restrictions, both for

       batchsize and for the remainder */

    && (batchsz = compute_batchsize(r), 1)

    && (e->genus->okp(e, 0, ((const R *)0) + 1, 2 * batchsz, 0,

          m, mb, mb + batchsz, 2, plnr))

    && (e->genus->okp(e, 0, ((const R *)0) + 1, 2 * batchsz, 0,

          m, mb, me, 2, plnr))

    );

}

static int applicable(const S *ego,

          INT r, INT irs, INT ors,

          INT m, INT ms,

          INT v, INT ivs, INT ovs,

          INT mb, INT me,

          R *rio, R *iio,

          const planner *plnr, INT *extra_iter)

{

     if (ego->bufferedp) {

    *extra_iter = 0;

    if (!applicable0_buf(ego,

             r, irs, ors, m, ms, v, ivs, ovs, mb, me,

             rio, iio, plnr))

         return 0;

     } else {

    if (!applicable0(ego,

         r, irs, ors, m, ms, v, ivs, ovs, mb, me,

         rio, iio, plnr, extra_iter))

         return 0;

     }

     if (NO_UGLYP(plnr) && X(ct_uglyp)((ego->bufferedp? (INT)512 : (INT)16),

               v, m * r, r))

    return 0;

     if (m * r > 262144 && NO_FIXED_RADIX_LARGE_NP(plnr))

    return 0;

     return 1;

}

static plan *mkcldw(const ct_solver *ego_,

        INT r, INT irs, INT ors,

        INT m, INT ms,

        INT v, INT ivs, INT ovs,

        INT mstart, INT mcount,

        R *rio, R *iio,

        planner *plnr)

{

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

     P *pln;

     const ct_desc *e = ego->desc;

     INT extra_iter;

     static const plan_adt padt = {

    0, awake, print, destroy

     };

     A(mstart >= 0 && mstart + mcount <= m);

     if (!applicable(ego,

         r, irs, ors, m, ms, v, ivs, ovs, mstart, mstart + mcount,

         rio, iio, plnr, &extra_iter))

          return (plan *)0;

     if (ego->bufferedp) {

    pln = MKPLAN_DFTW(P, &padt, apply_buf);

     } else {

    pln = MKPLAN_DFTW(P, &padt, extra_iter ? apply_extra_iter : apply);

     }

     pln->k = ego->k;

     pln->rs = X(mkstride)(r, irs);

     pln->td = 0;

     pln->r = r;

     pln->m = m;

     pln->ms = ms;

     pln->v = v;

     pln->vs = ivs;

     pln->mb = mstart;

     pln->me = mstart + mcount;

     pln->slv = ego;

     pln->brs = X(mkstride)(r, 2 * compute_batchsize(r));

     pln->extra_iter = extra_iter;

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

     X(ops_madd2)(v * (mcount/e->genus->vl), &e->ops, &pln->super.super.ops);

     if (ego->bufferedp) {

    /* 8 load/stores * N * V */

    pln->super.super.ops.other += 8 * r * mcount * v;

     }

     pln->super.super.could_prune_now_p =

    (!ego->bufferedp && r >= 5 && r < 64 && m >= r);

     return &(pln->super.super);

}

static void regone(planner *plnr, kdftw codelet,

       const ct_desc *desc, int dec, int bufferedp)

{

     S *slv = (S *)X(mksolver_ct)(sizeof(S), desc->radix, dec, mkcldw, 0);

     slv->k = codelet;

     slv->desc = desc;

     slv->bufferedp = bufferedp;

     REGISTER_SOLVER(plnr, &(slv->super.super));

     if (X(mksolver_ct_hook)) {

    slv = (S *)X(mksolver_ct_hook)(sizeof(S), desc->radix,

           dec, mkcldw, 0);

    slv->k = codelet;

    slv->desc = desc;

    slv->bufferedp = bufferedp;

    REGISTER_SOLVER(plnr, &(slv->super.super));

     }

}

void X(regsolver_ct_directw)(planner *plnr, kdftw codelet,

           const ct_desc *desc, int dec)

{

     regone(plnr, codelet, desc, dec, /* bufferedp */ 0);

     regone(plnr, codelet, desc, dec, /* bufferedp */ 1);

}