/* * Encog(tm) Core v3.4 - Java Version * http://www.heatonresearch.com/encog/ * https://github.com/encog/encog-java-core * Copyright 2008-2016 Heaton Research, Inc. * * Licensed 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. * * For more information on Heaton Research copyrights, licenses * and trademarks visit: * http://www.heatonresearch.com/copyright */ package org.encog.engine.network.activation; import org.encog.ml.factory.MLActivationFactory; import org.encog.util.obj.ActivationUtil; /** * The Linear layer is really not an activation function at all. The input is * simply passed on, unmodified, to the output. This activation function is * primarily theoretical and of little actual use. Usually an activation * function that scales between 0 and 1 or -1 and 1 should be used. */ public class ActivationLinear implements ActivationFunction { /** * Default empty parameters. */ public static final double P[] = new double[0]; /** * Default empty parameters. */ public static final String N[] = new String[0]; /** * Serial id for this class. */ private static final long serialVersionUID = -5356580554235104944L; /** * The parameters. */ private final double[] params; /** * Construct a linear activation function, with a slope of 1. */ public ActivationLinear() { this.params = new double[0]; } /** * {@inheritDoc} */ @Override public final void activationFunction(final double[] x, final int start, final int size) { } /** * @return The object cloned. */ @Override public final ActivationFunction clone() { return new ActivationLinear(); } /** * {@inheritDoc} */ @Override public final double derivativeFunction(final double b, final double a) { return 1; } /** * {@inheritDoc} */ @Override public final String[] getParamNames() { final String[] result = {}; return result; } /** * {@inheritDoc} */ @Override public final double[] getParams() { return this.params; } /** * @return Return true, linear has a 1 derivative. */ @Override public final boolean hasDerivative() { return true; } /** * {@inheritDoc} */ @Override public final void setParam(final int index, final double value) { this.params[index] = value; } /** * {@inheritDoc} */ @Override public String getFactoryCode() { return ActivationUtil.generateActivationFactory(MLActivationFactory.AF_LINEAR, this); } @Override public String getLabel() { return "linear"; } }