org.nd4j.linalg.schedule.PolySchedule Maven / Gradle / Ivy
/*******************************************************************************
* Copyright (c) 2015-2018 Skymind, Inc.
*
* This program and the accompanying materials are made available under the
* terms of the Apache License, Version 2.0 which is available at
* https://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.
*
* SPDX-License-Identifier: Apache-2.0
******************************************************************************/
package org.nd4j.linalg.schedule;
import lombok.Data;
import org.nd4j.shade.jackson.annotation.JsonProperty;
/**
*
* Polynomial decay schedule, with 3 parameters: initial value, maxIter, power.
* Note that the value will be 0 after maxIter, otherwise is given by:
* value(i) = initialValue * (1 + i/maxIter)^(-power)
* where i is the iteration or epoch (depending on the setting)
*
* @author Alex Black
*/
@Data
public class PolySchedule implements ISchedule {
private final ScheduleType scheduleType;
private final double initialValue;
private final double power;
private final int maxIter;
public PolySchedule(@JsonProperty("scheduleType") ScheduleType scheduleType,
@JsonProperty("initialValue") double initialValue,
@JsonProperty("power") double power,
@JsonProperty("maxIter") int maxIter){
this.scheduleType = scheduleType;
this.initialValue = initialValue;
this.power = power;
this.maxIter = maxIter;
}
@Override
public double valueAt(int iteration, int epoch) {
int i = (scheduleType == ScheduleType.ITERATION ? iteration : epoch);
if( i >= maxIter ){
return 0;
}
return initialValue * Math.pow(1 + i / (double)maxIter, power);
}
@Override
public PolySchedule clone() {
return new PolySchedule(scheduleType, initialValue, power, maxIter);
}
}