org.nd4j.linalg.schedule.SigmoidSchedule Maven / Gradle / Ivy
package org.nd4j.linalg.schedule;
import lombok.Data;
import org.nd4j.shade.jackson.annotation.JsonProperty;
/**
* Sigmoid decay schedule, with 3 parameters: initial value, gamma and stepSize.
* value(i) = initialValue * 1.0 / (1 + exp(-gamma * (iter - stepSize)))
* where i is the iteration or epoch (depending on the setting)
*
* @author Alex Black
*/
@Data
public class SigmoidSchedule implements ISchedule {
private final ScheduleType scheduleType;
private final double initialValue;
private final double gamma;
private final int stepSize;
public SigmoidSchedule(@JsonProperty("scheduleType") ScheduleType scheduleType,
@JsonProperty("initialValue") double initialValue,
@JsonProperty("gamma") double gamma,
@JsonProperty("stepSize") int stepSize){
this.scheduleType = scheduleType;
this.initialValue = initialValue;
this.gamma = gamma;
this.stepSize = stepSize;
}
@Override
public double valueAt(int iteration, int epoch) {
int i = (scheduleType == ScheduleType.ITERATION ? iteration : epoch);
return initialValue / (1.0 + Math.exp(-gamma * (i - stepSize)));
}
@Override
public ISchedule clone() {
return new SigmoidSchedule(scheduleType, initialValue, gamma, stepSize);
}
}