/*
* 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.neural.freeform.basic;
import java.io.Serializable;
import java.util.ArrayList;
import java.util.List;
import org.encog.engine.network.activation.ActivationFunction;
import org.encog.neural.freeform.FreeformConnection;
import org.encog.neural.freeform.InputSummation;
/**
* Provides a basic implementation of an input summation. The inputs are summed
* and applied to the activation function.
*/
public class BasicActivationSummation implements InputSummation, Serializable {
/**
* Serial id.
*/
private static final long serialVersionUID = 1L;
/**
* The activation function to use.
*/
private ActivationFunction activationFunction;
/**
* The inputs.
*/
private final List<FreeformConnection> inputs = new ArrayList<FreeformConnection>();
/**
* THe pre-activation summation.
*/
private double sum;
/**
* Construct the activation summation.
* @param theActivationFunction The activation function.
*/
public BasicActivationSummation(
final ActivationFunction theActivationFunction) {
this.activationFunction = theActivationFunction;
}
/**
* {@inheritDoc}
*/
@Override
public void add(final FreeformConnection connection) {
this.inputs.add(connection);
}
/**
* {@inheritDoc}
*/
@Override
public double calculate() {
final double[] sumArray = new double[1];
this.sum = 0;
// sum the input connections
for (final FreeformConnection connection : this.inputs) {
connection.getSource().performCalculation();
this.sum += connection.getWeight()
* connection.getSource().getActivation();
}
// perform the activation function
sumArray[0] = this.sum;
this.activationFunction
.activationFunction(sumArray, 0, sumArray.length);
return sumArray[0];
}
/**
* {@inheritDoc}
*/
@Override
public ActivationFunction getActivationFunction() {
return this.activationFunction;
}
/**
* {@inheritDoc}
*/
@Override
public double getSum() {
return this.sum;
}
/**
* {@inheritDoc}
*/
@Override
public List<FreeformConnection> list() {
return this.inputs;
}
/**
* Set the activation function.
* @param activationFunction The activation function.
*/
public void setActivationFunction(
final ActivationFunction activationFunction) {
this.activationFunction = activationFunction;
}
}