/**
 * @file randomized_svd.cpp
 * @author Marcus Edel
 *
 * Implementation of the randomized SVD method.
 *
 * mlpack is free software; you may redistribute it and/or modify it under the
 * terms of the 3-clause BSD license.  You should have received a copy of the
 * 3-clause BSD license along with mlpack.  If not, see
 * http://www.opensource.org/licenses/BSD-3-Clause for more information.
 */

#include "randomized_svd.hpp"

namespace mlpack {
namespace svd {

RandomizedSVD::RandomizedSVD(const arma::mat& data,
                             arma::mat& u,
                             arma::vec& s,
                             arma::mat& v,
                             const size_t iteratedPower,
                             const size_t maxIterations,
                             const size_t rank,
                             const double eps) :
    iteratedPower(iteratedPower),
    maxIterations(maxIterations),
    eps(eps)
{
  if (rank == 0)
  {
    Apply(data, u, s, v, data.n_rows);
  }
  else
  {
    Apply(data, u, s, v, rank);
  }
}

RandomizedSVD::RandomizedSVD(const size_t iteratedPower,
                             const size_t maxIterations,
                             const double eps) :
    iteratedPower(iteratedPower),
    maxIterations(maxIterations),
    eps(eps)
{
  /* Nothing to do here */
}


void RandomizedSVD::Apply(const arma::sp_mat& data,
                          arma::mat& u,
                          arma::vec& s,
                          arma::mat& v,
                          const size_t rank)
{
  // Center the data into a temporary matrix for sparse matrix.
  arma::sp_mat rowMean = arma::sum(data, 1) / data.n_cols;

  Apply(data, u, s, v, rank, rowMean);
}

void RandomizedSVD::Apply(const arma::mat& data,
                          arma::mat& u,
                          arma::vec& s,
                          arma::mat& v,
                          const size_t rank)
{
  // Center the data into a temporary matrix.
  arma::mat rowMean = arma::sum(data, 1) / data.n_cols + eps;

  Apply(data, u, s, v, rank, rowMean);
}

} // namespace svd
} // namespace mlpack