/* ---------------------------------------------------------------------
* Numenta Platform for Intelligent Computing (NuPIC)
* Copyright (C) 2014, Numenta, Inc. Unless you have an agreement
* with Numenta, Inc., for a separate license for this software code, the
* following terms and conditions apply:
*
* This program is free software: you can redistribute it and/or modify
* it under the terms of the GNU Affero Public License version 3 as
* published by the Free Software Foundation.
*
* This program 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 Affero Public License for more details.
*
* You should have received a copy of the GNU Affero Public License
* along with this program. If not, see http://www.gnu.org/licenses.
*
* http://numenta.org/licenses/
* ---------------------------------------------------------------------
*/
package org.numenta.nupic.util;
/**
* Allows storage of array data in sparse form, meaning that the indexes
* of the data stored are maintained while empty indexes are not. This allows
* savings in memory and computational efficiency because iterative algorithms
* need only query indexes containing valid data. The dimensions of matrix defined
* at construction time and immutable - matrix fixed size data structure.
*
* @author David Ray
* @author Jose Luis Martin
*
* @param <T>
*/
public interface SparseMatrix<T> extends FlatMatrix<T>{
/**
* Returns a sorted array of occupied indexes.
* @return a sorted array of occupied indexes.
*/
int[] getSparseIndices();
/**
* Returns an array of all the flat indexes that can be
* computed from the current configuration.
* @return
*/
int[] get1DIndexes();
/**
* Uses the specified {@link TypeFactory} to return an array
* filled with the specified object type, according this {@code SparseMatrix}'s
* configured dimensions
*
* @param factory a factory to make a specific type
* @return the dense array
*/
T[] asDense(TypeFactory<T> factory);
}