/*
 * Copyright © 2004-2011 Ondra Kamenik
 * Copyright © 2019-2023 Dynare Team
 *
 * This file is part of Dynare.
 *
 * Dynare 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 3 of the License, or
 * (at your option) any later version.
 *
 * Dynare 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 Dynare.  If not, see <https://www.gnu.org/licenses/>.
 */

#include "KronUtils.hh"
#include "int_power.hh"

void
KronUtils::multAtLevel(int level, const QuasiTriangular& t, KronVector& x)
{
  if (0 < level && level < x.getDepth())
    for (int i = 0; i < x.getM(); i++)
      {
        KronVector xi(x, i);
        multAtLevel(level, t, xi);
      }
  else if (0 == level && 0 < x.getDepth())
    {
      GeneralMatrix tmp(x, x.getN(), power(x.getM(), x.getDepth()));
      t.multLeftOther(tmp);
    }
  else if (0 == level && 0 == x.getDepth())
    {
      Vector b(const_cast<const KronVector&>(x));
      t.multVec(x, b);
    }
  else // 0 < level == depth
    t.multKron(x);
}

void
KronUtils::multAtLevelTrans(int level, const QuasiTriangular& t, KronVector& x)
{
  if (0 < level && level < x.getDepth())
    for (int i = 0; i < x.getM(); i++)
      {
        KronVector xi(x, i);
        multAtLevelTrans(level, t, xi);
      }
  else if (0 == level && 0 < x.getDepth())
    {
      GeneralMatrix tmp(x, x.getN(), power(x.getM(), x.getDepth()));
      t.multLeftOtherTrans(tmp);
    }
  else if (level == 0 && 0 == x.getDepth())
    {
      Vector b(const_cast<const KronVector&>(x));
      t.multVecTrans(x, b);
    }
  else // 0 < level == depth
    t.multKronTrans(x);
}

void
KronUtils::multKron(const QuasiTriangular& f, const QuasiTriangular& k, KronVector& x)
{
  multAtLevel(0, k, x);
  if (x.getDepth() > 0)
    for (int level = 1; level <= x.getDepth(); level++)
      multAtLevelTrans(level, f, x);
}
