/**
* Copyright 2010 Neuroph Project http://neuroph.sourceforge.net
*
* 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.
*/
package org.neuroph.core.transfer;
import java.io.Serializable;
import org.neuroph.util.Properties;
/**
* Step neuron transfer function.
* y = yHigh, x > 0
* y = yLow, x <= 0
*
* @author Zoran Sevarac <sevarac@gmail.com>
*/
public class Step extends TransferFunction implements Serializable {
/**
* The class fingerprint that is set to indicate serialization
* compatibility with a previous version of the class.
*/
private static final long serialVersionUID = 1L;
/**
* Output value for high output level
*/
private double yHigh = 1d;
/**
* Output value for low output level
*/
private double yLow = 0d;
/**
* Creates an instance of Step transfer function
*/
public Step() {
}
/**
* Creates an instance of Step transfer function with specified properties
*/
public Step(Properties properties) {
try {
this.yHigh = (Double)properties.getProperty("transferFunction.yHigh");
this.yLow = (Double)properties.getProperty("transferFunction.yLow");
} catch (NullPointerException e) {
// if properties are not set just leave default values
} catch (NumberFormatException e) {
System.err.println("Invalid transfer function properties! Using default values.");
}
}
@Override
public double getOutput(double net) {
if (net > 0d)
return yHigh;
else
return yLow;
}
/**
* Returns output value for high output level
* @return output value for high output level
*/
public double getYHigh() {
return this.yHigh;
}
/**
* Set output value for the high output level
* @param yHigh value for the high output level
*/
public void setYHigh(double yHigh) {
this.yHigh = yHigh;
}
/**
* Returns output value for low output level
* @return output value for low output level
*/
public double getYLow() {
return this.yLow;
}
/**
* Set output value for the low output level
* @param yLow value for the low output level
*/
public void setYLow(double yLow) {
this.yLow = yLow;
}
/**
* Returns the properties of this function
* @return properties of this function
*/
public Properties getProperties() {
Properties properties = new Properties();
properties.setProperty("transferFunction.yHigh", new Double(yHigh).toString());
properties.setProperty("transferFunction.yLow", new Double(yLow).toString());
return properties;
}
}