/*
* Licensed to the Apache Software Foundation (ASF) under one or more
* contributor license agreements. See the NOTICE file distributed with
* this work for additional information regarding copyright ownership.
* The ASF licenses this file to You 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.apache.mahout.classifier.sgd;
import org.apache.mahout.classifier.AbstractVectorClassifier;
import org.apache.mahout.math.Vector;
/**
* Provides the ability to inject a gradient into the SGD logistic regresion.
* Typical uses of this are to use a ranking score such as AUC instead of a
* normal loss function.
*/
public interface Gradient {
Vector apply(String groupKey, int actual, Vector instance, AbstractVectorClassifier classifier);
}