/* -*- mode: C++; tab-width: 8; indent-tabs-mode: t; c-basic-offset: 8 -*- */
// vim:sts=8:sw=8:ts=8:noet:sr:cino=>s,f0,{0,g0,(0,\:0,t0,+0,=s
/*
 * Copyright (C) 2014 the FFLAS-FFPACK group
 *
 * Written by   Bastien Vialla <bastien.vialla@lirmm.fr>
 *
 *
 * ========LICENCE========
 * This file is part of the library FFLAS-FFPACK.
 *
 * FFLAS-FFPACK is free software: you can redistribute it and/or modify
 * it under the terms of the  GNU Lesser General Public
 * License as published by the Free Software Foundation; either
 * version 2.1 of the License, or (at your option) any later version.
 *
 * This library 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
 * Lesser General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public
 * License along with this library; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301 USA
 * ========LICENCE========
 *.
 */

#ifndef __FFLASFFPACK_fflas_sparse_CSR_pspmv_INL
#define __FFLASFFPACK_fflas_sparse_CSR_pspmv_INL

#ifdef __FFLASFFPACK_USE_TBB
#include "tbb/parallel_for.h"
#include "tbb/blocked_range.h"
#endif

 #include <thread>

namespace FFLAS {
namespace sparse_details_impl {
template <class Field>
inline void pfspmv(const Field &F, const Sparse<Field, SparseMatrix_t::CSR> &A, typename Field::ConstElement_ptr x_,
                   typename Field::Element_ptr y_, FieldCategories::GenericTag) {
    assume_aligned(dat, A.dat, (size_t)Alignment::CACHE_LINE);
    assume_aligned(col, A.col, (size_t)Alignment::CACHE_LINE);
    assume_aligned(st, A.st, (size_t)Alignment::CACHE_LINE);
    assume_aligned(x, x_, (size_t)Alignment::DEFAULT);
    assume_aligned(y, y_, (size_t)Alignment::DEFAULT);
#if defined(__FFLASFFPACK_USE_TBB)
    int step = __FFLASFFPACK_CACHE_LINE_SIZE / sizeof(typename Field::Element);
    tbb::parallel_for(tbb::blocked_range<index_t>(0, A.m, step),
                      [&F, &A, x, y, dat, col, st](const tbb::blocked_range<index_t> &r) {
        for (index_t i = r.begin(), end = r.end(); i < end; ++i) {
            auto start = st[i], stop = st[i + 1];
            index_t j = 0;
            index_t diff = stop - start;
            typename Field::Element y1, y2, y3, y4;
            F.assign(y1, F.zero);
            F.assign(y2, F.zero);
            F.assign(y3, F.zero);
            F.assign(y4, F.zero);
            for (; j < ROUND_DOWN(diff, 4); j += 4) {
                F.axpyin(y1, dat[start + j], x[col[start + j]]);
                F.axpyin(y2, dat[start + j + 1], x[col[start + j + 1]]);
                F.axpyin(y3, dat[start + j + 2], x[col[start + j + 2]]);
                F.axpyin(y4, dat[start + j + 3], x[col[start + j + 3]]);
            }
            for (; j < diff; ++j) {
                F.axpyin(y1, dat[start + j], x[col[start + j]]);
            }
            F.addin(y[i], y1);
            F.addin(y[i], y2);
            F.addin(y[i], y3);
            F.addin(y[i], y4);
        }
    });
#else
// The minimum size has to be a multiple of cache_line/sizeof(Element) to avoid
// cache coherency problem (ex: 8 for double, 16 for float)
#pragma omp parallel for
    for (index_t i = 0; i < A.m; ++i) {
        auto start = st[i], stop = st[i + 1];
        index_t j = 0;
        index_t diff = stop - start;
        typename Field::Element y1, y2, y3, y4;
        F.assign(y1, F.zero);
        F.assign(y2, F.zero);
        F.assign(y3, F.zero);
        F.assign(y4, F.zero);
        for (; j < ROUND_DOWN(diff, 4); j += 4) {
            F.axpyin(y1, dat[start + j], x[col[start + j]]);
            F.axpyin(y2, dat[start + j + 1], x[col[start + j + 1]]);
            F.axpyin(y3, dat[start + j + 2], x[col[start + j + 2]]);
            F.axpyin(y4, dat[start + j + 3], x[col[start + j + 3]]);
        }
        for (; j < diff; ++j) {
            F.axpyin(y1, dat[start + j], x[col[start + j]]);
        }
        F.addin(y[i], y1);
        F.addin(y[i], y2);
        F.addin(y[i], y3);
        F.addin(y[i], y4);
    }
#endif
}

template<class Field>
inline void pfspmv_task(const Field &F, const Sparse<Field, SparseMatrix_t::CSR> &A, typename Field::ConstElement_ptr x_,
                   typename Field::Element_ptr y_, const index_t iStart, const index_t iStop, FieldCategories::UnparametricTag) {
    assume_aligned(dat, A.dat, (size_t)Alignment::CACHE_LINE);
    assume_aligned(col, A.col, (size_t)Alignment::CACHE_LINE);
    assume_aligned(st, A.st, (size_t)Alignment::CACHE_LINE);
    assume_aligned(x, x_, (size_t)Alignment::DEFAULT);
    assume_aligned(y, y_, (size_t)Alignment::DEFAULT);
    for(index_t i = iStart ; i < iStop ; ++i){
        auto start = st[i], stop = st[i + 1];
        index_t j = 0;
        index_t diff = stop - start;
        typename Field::Element y1 = 0, y2 = 0, y3 = 0, y4 = 0;
        for (; j < ROUND_DOWN(diff, 4); j += 4) {
            y1 += dat[start + j] * x[col[start + j]];
            y2 += dat[start + j + 1] * x[col[start + j + 1]];
            y3 += dat[start + j + 2] * x[col[start + j + 2]];
            y4 += dat[start + j + 3] * x[col[start + j + 3]];
        }
        for (; j < diff; ++j) {
            y1 += dat[start + j] * x[col[start + j]];
        }
        y[i] += y1 + y2 + y3 + y4;
    }
}

template <class Field>
inline void pfspmv(const Field &F, const Sparse<Field, SparseMatrix_t::CSR> &A, typename Field::ConstElement_ptr x_,
                   typename Field::Element_ptr y_, FieldCategories::UnparametricTag) {
    assume_aligned(dat, A.dat, (size_t)Alignment::CACHE_LINE);
    assume_aligned(col, A.col, (size_t)Alignment::CACHE_LINE);
    assume_aligned(st, A.st, (size_t)Alignment::CACHE_LINE);
    assume_aligned(x, x_, (size_t)Alignment::DEFAULT);
    assume_aligned(y, y_, (size_t)Alignment::DEFAULT);
#if defined(__FFLASFFPACK_USE_TBB)
    int step = __FFLASFFPACK_CACHE_LINE_SIZE / sizeof(typename Field::Element);
    tbb::parallel_for(tbb::blocked_range<index_t>(0, A.m, step),
                      [&F, &A, x, y, dat, col, st](const tbb::blocked_range<index_t> &r) {
        for (index_t i = r.begin(), end = r.end(); i < end; ++i) {
            auto start = st[i], stop = st[i + 1];
            index_t j = 0;
            index_t diff = stop - start;
            typename Field::Element y1 = 0, y2 = 0, y3 = 0, y4 = 0;
            for (; j < ROUND_DOWN(diff, 4); j += 4) {
                y1 += dat[start + j] * x[col[start + j]];
                y2 += dat[start + j + 1] * x[col[start + j + 1]];
                y3 += dat[start + j + 2] * x[col[start + j + 2]];
                y4 += dat[start + j + 3] * x[col[start + j + 3]];
            }
            for (; j < diff; ++j) {
                y1 += dat[start + j] * x[col[start + j]];
            }
            y[i] += y1 + y2 + y3 + y4;
        }
    });
#else
// #pragma omp parallel for schedule(static, 8)
//     for (index_t i = 0; i < A.m; ++i) {
//         auto start = st[i], stop = st[i + 1];
//         index_t j = 0;
//         index_t diff = stop - start;
//         typename Field::Element y1 = 0, y2 = 0, y3 = 0, y4 = 0;
//         for (; j < ROUND_DOWN(diff, 4); j += 4) {
//             y1 += dat[start + j] * x[col[start + j]];
//             y2 += dat[start + j + 1] * x[col[start + j + 1]];
//             y3 += dat[start + j + 2] * x[col[start + j + 2]];
//             y4 += dat[start + j + 3] * x[col[start + j + 3]];
//         }
//         for (; j < diff; ++j) {
//             y1 += dat[start + j] * x[col[start + j]];
//         }
//         y[i] += y1 + y2 + y3 + y4;
//     }
    std::vector<std::thread> pool(6);

#endif
}

template <class Field>
inline void pfspmv(const Field &F, const Sparse<Field, SparseMatrix_t::CSR> &A, typename Field::ConstElement_ptr x_,
                   typename Field::Element_ptr y_, const int64_t kmax) {
    assume_aligned(dat, A.dat, (size_t)Alignment::CACHE_LINE);
    assume_aligned(col, A.col, (size_t)Alignment::CACHE_LINE);
    assume_aligned(st, A.st, (size_t)Alignment::CACHE_LINE);
    assume_aligned(x, x_, (size_t)Alignment::DEFAULT);
    assume_aligned(y, y_, (size_t)Alignment::DEFAULT);
#if defined(__FFLASFFPACK_USE_TBB)
    int step = __FFLASFFPACK_CACHE_LINE_SIZE / sizeof(typename Field::Element);
    tbb::parallel_for(tbb::blocked_range<index_t>(0, A.m, step),
                      [&F, &A, x, y, kmax, dat, col, st](const tbb::blocked_range<index_t> &r) {
        for (index_t i = r.begin(), end = r.end(); i < end; ++i) {
            index_t j = st[i];
            index_t j_loc = j;
            index_t j_end = st[i + 1];
            index_t block = (j_end - j_loc) / kmax;
            for (index_t l = 0; l < (index_t)block; ++l) {
                j_loc += kmax;
                for (; j < j_loc; ++j) {
                    y[i] += dat[j] * x[col[j]];
                }
                F.reduce(y[i]);
            }
            for (; j < j_end; ++j) {
                y[i] += dat[j] * x[col[j]];
            }
            F.reduce(y[i]);
        }
    });
#else
#pragma omp parallel for
    for (index_t i = 0; i < A.m; ++i) {
        index_t j = st[i];
        index_t j_loc = j;
        index_t j_end = st[i + 1];
        index_t block = (j_end - j_loc) / kmax;
        for (index_t l = 0; l < (index_t)block; ++l) {
            j_loc += kmax;
            for (; j < j_loc; ++j) {
                y[i] += dat[j] * x[col[j]];
            }
            F.reduce(y[i]);
        }
        for (; j < j_end; ++j) {
            y[i] += dat[j] * x[col[j]];
        }
        F.reduce(y[i]);
    }
#endif
}

template <class Field>
inline void pfspmv_one(const Field &F, const Sparse<Field, SparseMatrix_t::CSR_ZO> &A,
                       typename Field::ConstElement_ptr x_, typename Field::Element_ptr y_,
                       FieldCategories::GenericTag) {
    assume_aligned(col, A.col, (size_t)Alignment::CACHE_LINE);
    assume_aligned(st, A.st, (size_t)Alignment::CACHE_LINE);
    assume_aligned(x, x_, (size_t)Alignment::DEFAULT);
    assume_aligned(y, y_, (size_t)Alignment::DEFAULT);
    size_t am = A.m;
    SYNCH_GROUP(
	  FORBLOCK1D(it, am, SPLITTER(NUM_THREADS),
	  TASK(MODE(CONSTREFERENCE(F) READ(col, st, x) READWRITE(y)),
	  for (index_t i = it.begin(); i < it.end(); ++i) {
        auto start = st[i];
        auto stop = st[i + 1];
        index_t j = 0;
        index_t diff = stop - start;
        typename Field::Element y1;
        typename Field::Element y2;
        typename Field::Element y3;
        typename Field::Element y4;
        F.assign(y1, F.zero);
        F.assign(y2, F.zero);
        F.assign(y3, F.zero);
        F.assign(y4, F.zero);
        for (; j < ROUND_DOWN(diff, 4); j += 4) {
            F.addin(y1, x[col[start + j]]);
            F.addin(y2, x[col[start + j + 1]]);
            F.addin(y3, x[col[start + j + 2]]);
            F.addin(y4, x[col[start + j + 3]]);
        }
        for (; j < diff; ++j) {
            F.addin(y1, x[col[start + j]]);
        }
        F.addin(y[i], y1);
        F.addin(y[i], y2);
        F.addin(y[i], y3);
        F.addin(y[i], y4);
      }
           );
                 );
                );
}

template <class Field>
inline void pfspmv_mone(const Field &F, const Sparse<Field, SparseMatrix_t::CSR_ZO> &A,
                        typename Field::ConstElement_ptr x_, typename Field::Element_ptr y_,
                        FieldCategories::GenericTag) {
    assume_aligned(col, A.col, (size_t)Alignment::CACHE_LINE);
    assume_aligned(st, A.st, (size_t)Alignment::CACHE_LINE);
    assume_aligned(x, x_, (size_t)Alignment::DEFAULT);
    assume_aligned(y, y_, (size_t)Alignment::DEFAULT);
    size_t am = A.m;
    SYNCH_GROUP(
	  FORBLOCK1D(it, am, SPLITTER(NUM_THREADS),
	  TASK(MODE(CONSTREFERENCE(F) READ(col, st, x) READWRITE(y)),
	  for (index_t i = it.begin(); i < it.end(); ++i) {
        auto start = st[i];
        auto stop = st[i + 1];
        index_t j = 0;
        index_t diff = stop - start;
        typename Field::Element y1;
        typename Field::Element y2;
        typename Field::Element y3;
        typename Field::Element y4;
        F.assign(y1, F.zero);
        F.assign(y2, F.zero);
        F.assign(y3, F.zero);
        F.assign(y4, F.zero);
        for (; j < ROUND_DOWN(diff, 4); j += 4) {
            F.addin(y1, x[col[start + j]]);
            F.addin(y2, x[col[start + j + 1]]);
            F.addin(y3, x[col[start + j + 2]]);
            F.addin(y4, x[col[start + j + 3]]);
        }
        for (; j < diff; ++j) {
            F.addin(y1, x[col[start + j]]);
        }
        F.subin(y[i], y1);
        F.subin(y[i], y2);
        F.subin(y[i], y3);
        F.subin(y[i], y4);
      }
           );
                 );
                );
}

template <class Field>
inline void pfspmv_one(const Field &F, const Sparse<Field, SparseMatrix_t::CSR_ZO> &A,
                       typename Field::ConstElement_ptr x_, typename Field::Element_ptr y_,
                       FieldCategories::UnparametricTag) {
    assume_aligned(col, A.col, (size_t)Alignment::CACHE_LINE);
    assume_aligned(st, A.st, (size_t)Alignment::CACHE_LINE);
    assume_aligned(x, x_, (size_t)Alignment::DEFAULT);
    assume_aligned(y, y_, (size_t)Alignment::DEFAULT);
#if defined(__FFLASFFPACK_USE_TBB)
    int step = __FFLASFFPACK_CACHE_LINE_SIZE / sizeof(typename Field::Element);
    tbb::parallel_for(tbb::blocked_range<index_t>(0, A.m, step),
                      [&F, &A, x, y, col, st](const tbb::blocked_range<index_t> &r) {
        for (index_t i = r.begin(), end = r.end(); i < end; ++i) {
            auto start = st[i], stop = st[i + 1];
            index_t j = 0;
            index_t diff = stop - start;
            typename Field::Element y1 = 0, y2 = 0, y3 = 0, y4 = 0;
            for (; j < ROUND_DOWN(diff, 4); j += 4) {
                y1 += x[col[start + j]];
                y2 += x[col[start + j + 1]];
                y3 += x[col[start + j + 2]];
                y4 += x[col[start + j + 3]];
            }
            for (; j < diff; ++j) {
                y1 += x[col[start + j]];
            }
            y[i] += y1 + y2 + y3 + y4;
        }
    });
#else
#pragma omp parallel for
    for (index_t i = 0; i < A.m; ++i) {
        auto start = st[i], stop = st[i + 1];
        index_t j = 0;
        index_t diff = stop - start;
        typename Field::Element y1 = 0, y2 = 0, y3 = 0, y4 = 0;
        for (; j < ROUND_DOWN(diff, 4); j += 4) {
            y1 += x[col[start + j]];
            y2 += x[col[start + j + 1]];
            y3 += x[col[start + j + 2]];
            y4 += x[col[start + j + 3]];
        }
        for (; j < diff; ++j) {
            y1 += x[col[start + j]];
        }
        y[i] += y1 + y2 + y3 + y4;
    }
#endif
}

template <class Field>
inline void pfspmv_mone(const Field &F, const Sparse<Field, SparseMatrix_t::CSR_ZO> &A,
                        typename Field::ConstElement_ptr x_, typename Field::Element_ptr y_,
                        FieldCategories::UnparametricTag) {
    assume_aligned(col, A.col, (size_t)Alignment::CACHE_LINE);
    assume_aligned(st, A.st, (size_t)Alignment::CACHE_LINE);
    assume_aligned(x, x_, (size_t)Alignment::DEFAULT);
    assume_aligned(y, y_, (size_t)Alignment::DEFAULT);
#if defined(__FFLASFFPACK_USE_TBB)
    int step = __FFLASFFPACK_CACHE_LINE_SIZE / sizeof(typename Field::Element);
    tbb::parallel_for(tbb::blocked_range<index_t>(0, A.m, step),
                      [&F, &A, x, y, col, st](const tbb::blocked_range<index_t> &r) {
        for (index_t i = r.begin(), end = r.end(); i < end; ++i) {
            auto start = st[i], stop = st[i + 1];
            index_t j = 0;
            index_t diff = stop - start;
            typename Field::Element y1 = 0, y2 = 0, y3 = 0, y4 = 0;
            for (; j < ROUND_DOWN(diff, 4); j += 4) {
                y1 += x[col[start + j]];
                y2 += x[col[start + j + 1]];
                y3 += x[col[start + j + 2]];
                y4 += x[col[start + j + 3]];
            }
            for (; j < diff; ++j) {
                y1 += x[col[start + j]];
            }
            y[i] -= y1 + y2 + y3 + y4;
        }
    });
#else
#pragma omp parallel for
    for (index_t i = 0; i < A.m; ++i) {
        auto start = st[i], stop = st[i + 1];
        index_t j = 0;
        index_t diff = stop - start;
        typename Field::Element y1 = 0, y2 = 0, y3 = 0, y4 = 0;
        for (; j < ROUND_DOWN(diff, 4); j += 4) {
            y1 += x[col[start + j]];
            y2 += x[col[start + j + 1]];
            y3 += x[col[start + j + 2]];
            y4 += x[col[start + j + 3]];
        }
        for (; j < diff; ++j) {
            y1 += x[col[start + j]];
        }
        y[i] -= y1 + y2 + y3 + y4;
    }
#endif
}

} // CSR_details

} // FFLAS

#endif //  __FFLASFFPACK_fflas_CSR_pspmv_INL
