| /* |
| * Licensed to the Apache Software Foundation (ASF) under one or more |
| * contributor license agreements. See the NOTICE file distributed with |
| * this work for additional information regarding copyright ownership. |
| * The ASF licenses this file to You under the Apache License, Version 2.0 |
| * (the "License"); you may not use this file except in compliance with |
| * the License. You may obtain a copy of the License at |
| * |
| * http://www.apache.org/licenses/LICENSE-2.0 |
| * |
| * Unless required by applicable law or agreed to in writing, software |
| * distributed under the License is distributed on an "AS IS" BASIS, |
| * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. |
| * See the License for the specific language governing permissions and |
| * limitations under the License. |
| */ |
| package org.apache.commons.math4.linear; |
| |
| import org.apache.commons.math4.Field; |
| import org.apache.commons.math4.FieldElement; |
| import org.apache.commons.math4.util.OpenIntToFieldHashMap; |
| |
| /** |
| * Sparse matrix implementation based on an open addressed map. |
| * |
| * <p> |
| * Caveat: This implementation assumes that, for any {@code x}, |
| * the equality {@code x * 0d == 0d} holds. But it is is not true for |
| * {@code NaN}. Moreover, zero entries will lose their sign. |
| * Some operations (that involve {@code NaN} and/or infinities) may |
| * thus give incorrect results. |
| * </p> |
| * @param <T> the type of the field elements |
| * @since 2.0 |
| */ |
| public class SparseFieldMatrix<T extends FieldElement<T>> extends AbstractFieldMatrix<T> { |
| |
| /** Storage for (sparse) matrix elements. */ |
| private final OpenIntToFieldHashMap<T> entries; |
| /** Row dimension. */ |
| private final int rows; |
| /** Column dimension. */ |
| private final int columns; |
| |
| /** |
| * Create a matrix with no data. |
| * |
| * @param field Field to which the elements belong. |
| */ |
| public SparseFieldMatrix(final Field<T> field) { |
| super(field); |
| rows = 0; |
| columns= 0; |
| entries = new OpenIntToFieldHashMap<>(field); |
| } |
| |
| /** |
| * Create a new {@code SparseFieldMatrix<T>} with the supplied row and column |
| * dimensions. |
| * |
| * @param field Field to which the elements belong. |
| * @param rowDimension Number of rows in the new matrix. |
| * @param columnDimension Number of columns in the new matrix. |
| * @throws org.apache.commons.math4.exception.NotStrictlyPositiveException |
| * if row or column dimension is not positive. |
| */ |
| public SparseFieldMatrix(final Field<T> field, |
| final int rowDimension, final int columnDimension) { |
| super(field, rowDimension, columnDimension); |
| this.rows = rowDimension; |
| this.columns = columnDimension; |
| entries = new OpenIntToFieldHashMap<>(field); |
| } |
| |
| /** |
| * Copy constructor. |
| * |
| * @param other Instance to copy. |
| */ |
| public SparseFieldMatrix(SparseFieldMatrix<T> other) { |
| super(other.getField(), other.getRowDimension(), other.getColumnDimension()); |
| rows = other.getRowDimension(); |
| columns = other.getColumnDimension(); |
| entries = new OpenIntToFieldHashMap<>(other.entries); |
| } |
| |
| /** |
| * Generic copy constructor. |
| * |
| * @param other Instance to copy. |
| */ |
| public SparseFieldMatrix(FieldMatrix<T> other){ |
| super(other.getField(), other.getRowDimension(), other.getColumnDimension()); |
| rows = other.getRowDimension(); |
| columns = other.getColumnDimension(); |
| entries = new OpenIntToFieldHashMap<>(getField()); |
| for (int i = 0; i < rows; i++) { |
| for (int j = 0; j < columns; j++) { |
| setEntry(i, j, other.getEntry(i, j)); |
| } |
| } |
| } |
| |
| /** {@inheritDoc} */ |
| @Override |
| public void addToEntry(int row, int column, T increment) { |
| checkRowIndex(row); |
| checkColumnIndex(column); |
| final int key = computeKey(row, column); |
| final T value = entries.get(key).add(increment); |
| if (getField().getZero().equals(value)) { |
| entries.remove(key); |
| } else { |
| entries.put(key, value); |
| } |
| } |
| |
| /** {@inheritDoc} */ |
| @Override |
| public FieldMatrix<T> copy() { |
| return new SparseFieldMatrix<>(this); |
| } |
| |
| /** {@inheritDoc} */ |
| @Override |
| public FieldMatrix<T> createMatrix(int rowDimension, int columnDimension) { |
| return new SparseFieldMatrix<>(getField(), rowDimension, columnDimension); |
| } |
| |
| /** {@inheritDoc} */ |
| @Override |
| public int getColumnDimension() { |
| return columns; |
| } |
| |
| /** {@inheritDoc} */ |
| @Override |
| public T getEntry(int row, int column) { |
| checkRowIndex(row); |
| checkColumnIndex(column); |
| return entries.get(computeKey(row, column)); |
| } |
| |
| /** {@inheritDoc} */ |
| @Override |
| public int getRowDimension() { |
| return rows; |
| } |
| |
| /** {@inheritDoc} */ |
| @Override |
| public void multiplyEntry(int row, int column, T factor) { |
| checkRowIndex(row); |
| checkColumnIndex(column); |
| final int key = computeKey(row, column); |
| final T value = entries.get(key).multiply(factor); |
| if (getField().getZero().equals(value)) { |
| entries.remove(key); |
| } else { |
| entries.put(key, value); |
| } |
| |
| } |
| |
| /** {@inheritDoc} */ |
| @Override |
| public void setEntry(int row, int column, T value) { |
| checkRowIndex(row); |
| checkColumnIndex(column); |
| if (getField().getZero().equals(value)) { |
| entries.remove(computeKey(row, column)); |
| } else { |
| entries.put(computeKey(row, column), value); |
| } |
| } |
| |
| /** |
| * Compute the key to access a matrix element. |
| * |
| * @param row Row index of the matrix element. |
| * @param column Column index of the matrix element. |
| * @return the key within the map to access the matrix element. |
| */ |
| private int computeKey(int row, int column) { |
| return row * columns + column; |
| } |
| } |