data_dependent_random_initializer.hpp

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#ifndef MLPACK_METHODS_SPARSE_CODING_DATA_DEPENDENT_RANDOM_INITIALIZER_HPP
#define MLPACK_METHODS_SPARSE_CODING_DATA_DEPENDENT_RANDOM_INITIALIZER_HPP

#include <mlpack/prereqs.hpp>
#include <mlpack/core/math/random.hpp>

namespace mlpack {
namespace sparse_coding {

class DataDependentRandomInitializer
{
 public:
  static void Initialize(const arma::mat& data,
                         const size_t atoms,
                         arma::mat& dictionary)
  {
    // Set the size of the dictionary.
    dictionary.set_size(data.n_rows, atoms);

    // Create each atom.
    for (size_t i = 0; i < atoms; ++i)
    {
      // Add three atoms together.
      dictionary.col(i) = (data.col(math::RandInt(data.n_cols)) +
          data.col(math::RandInt(data.n_cols)) +
          data.col(math::RandInt(data.n_cols)));

      // Now normalize the atom.
      dictionary.col(i) /= norm(dictionary.col(i), 2);
    }
  }
};

} // namespace sparse_coding
} // namespace mlpack

#endif