/**
* 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;
/**
* Ramp neuron transfer function.
*
* @author Zoran Sevarac <sevarac@gmail.com>
*/
public class Ramp 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;
/**
* The slope parametetar of the ramp function
*/
private double slope = 1d;
/**
* Threshold for the high output level
*/
private double xHigh = 1d;
/**
* Threshold for the low output level
*/
private double xLow = 0d;
/**
* Output value for the high output level
*/
private double yHigh = 1d;
/**
* Output value for the low output level
*/
private double yLow = 0d;
/**
* Creates an instance of Ramp transfer function with default settings
*/
public Ramp() {
}
/**
* Creates an instance of Ramp transfer function with specified settings
*/
public Ramp(double slope, double xLow, double xHigh, double yLow,
double yHigh) {
this.slope = slope;
this.xLow = xLow;
this.xHigh = xHigh;
this.yLow = yLow;
this.yHigh = yHigh;
}
/**
* Creates an instance of Ramp transfer function with specified properties.
*/
public Ramp(Properties properties) {
try {
this.slope = (Double)properties.getProperty("transferFunction.slope");
this.yHigh = (Double)properties.getProperty("transferFunction.yHigh");
this.yLow = (Double)properties.getProperty("transferFunction.yLow");
this.xHigh = (Double)properties.getProperty("transferFunction.xHigh");
this.xLow = (Double)properties.getProperty("transferFunction.xLow");
} 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 < this.xLow)
return this.yLow;
else if (net > this.xHigh)
return this.yHigh;
else
return (double) (slope * net);
}
/**
* Returns threshold value for the low output level
* @return threshold value for the low output level
*/
public double getXLow() {
return this.xLow;
}
/**
* Sets threshold for the low output level
* @param x threshold value for the low output level
*/
public void setXLow(double x) {
this.xLow = x;
}
/**
* Returns threshold value for the high output level
* @return threshold value for the high output level
*/
public double getXHigh() {
return this.xHigh;
}
/**
* Sets threshold for the high output level
* @param x threshold value for the high output level
*/
public void setXHigh(double x) {
this.xHigh = x;
}
/**
* Returns output value for low output level
* @return output value for low output level
*/
public double getYLow() {
return this.yLow;
}
/**
* Sets output value for the low output level
* @param y value for the low output level
*/
public void setYLow(double y) {
this.yLow = y;
}
/**
* Returns output value for high output level
* @return output value for high output level
*/
public double getYHigh() {
return this.yHigh;
}
/**
* Sets output value for the high output level
* @param y value for the high output level
*/
public void setYHigh(double y) {
this.yHigh = y;
}
}