/* checkers/Checker_ftrsm.inl
 * Copyright (C) 2016 Ashley Lesdalons
 *
 * Written by Ashley Lesdalons <Ashley.Lesdalons@e.ujf-grenoble.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_checker_ftrsm_INL
#define __FFLASFFPACK_checker_ftrsm_INL

namespace FFLAS {

    template <class Field>
    class CheckerImplem_ftrsm {

        const Field& F;
        typename Field::Element_ptr v,w;

    public:
        CheckerImplem_ftrsm(const Field& F_,
                            const size_t m, const size_t n,
                            const typename Field::Element alpha,
                            const typename Field::ConstElement_ptr B,
                            const size_t ldb)
        : F(F_),
        v(FFLAS::fflas_new(F_,n)),
        w(FFLAS::fflas_new(F_,m))
        {
            typename Field::RandIter G(F);
            init(G,m,n,B,ldb,alpha);
        }

        CheckerImplem_ftrsm(typename Field::RandIter &G,
                            const size_t m, const size_t n,
                            const typename Field::Element alpha,
                            const typename Field::ConstElement_ptr B,
                            const size_t ldb)
        : F(G.ring()),
        v(FFLAS::fflas_new(F,n)),
        w(FFLAS::fflas_new(F,m))
        {
            init(G,m,n,B,ldb,alpha);
        }

        ~CheckerImplem_ftrsm() {
            FFLAS::fflas_delete(v,w);
        }

        inline bool check(const FFLAS::FFLAS_SIDE side,
                          const FFLAS::FFLAS_UPLO uplo,
                          const FFLAS::FFLAS_TRANSPOSE trans,
                          const FFLAS::FFLAS_DIAG diag,
                          const size_t m, const size_t n,
#ifdef __FFLAS__TRSM_READONLY
                          typename Field::ConstElement_ptr
#else
                          typename Field::Element_ptr
#endif
                          A, size_t lda,
                          const typename Field::ConstElement_ptr X, size_t ldx) {
            size_t k = (side==FFLAS::FflasLeft?m:n);

            typename Field::Element_ptr v1 = FFLAS::fflas_new(F,k);
            FFLAS::finit(F,k,v1,1);

            if (side==FFLAS::FflasLeft) {
                // (Left) v1 <- X.v
                // (Left) v1 <- A.v1
                // (Left) w <- w - v1
                FFLAS::fgemv(F, FFLAS::FflasNoTrans, m, n, F.one, X, ldx, v, 1, F.zero, v1, 1);
                FFLAS::ftrmm(F, FFLAS::FflasLeft, uplo, trans, diag, k, 1, F.one, A, lda, v1, 1);
                FFLAS::fsubin(F, m, v1, 1, w, 1);
            } else {
                // (Right) v <- A.v
                // (Right) w <- X.v - w
                FFLAS::ftrmm(F, FFLAS::FflasLeft, uplo, trans, diag, k, 1, F.one, A, lda, v, 1);
                FFLAS::fgemv(F, FFLAS::FflasNoTrans, m, n, F.one, X, ldx, v, 1, F.mOne, w, 1);
            }


            FFLAS::fflas_delete(v1);

            bool pass = FFLAS::fiszero(F,m,1,w,1);
            if (!pass) throw FailureTrsmCheck();
            return pass;
        }

    private:
        inline void init(typename Field::RandIter &G, const size_t m, const size_t n, const typename Field::ConstElement_ptr B, size_t ldb, const typename Field::Element alpha) {
            FFLAS::finit(F,n,v,1);
            FFLAS::finit(F,m,w,1);
            FFLAS::frand(F,G,n,v,1);

            // w <- alpha.B.v
            FFLAS::fgemv(F, FFLAS::FflasNoTrans, m, n, alpha, B, ldb, v, 1, F.zero, w, 1);
        }
    };

}

#endif // __FFLASFFPACK_checker_ftrsm_INL
/* -*- mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 4 -*- */
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