001/*
002 * Licensed to the Apache Software Foundation (ASF) under one or more
003 * contributor license agreements.  See the NOTICE file distributed with
004 * this work for additional information regarding copyright ownership.
005 * The ASF licenses this file to You under the Apache License, Version 2.0
006 * (the "License"); you may not use this file except in compliance with
007 * the License.  You may obtain a copy of the License at
008 *
009 *      http://www.apache.org/licenses/LICENSE-2.0
010 *
011 * Unless required by applicable law or agreed to in writing, software
012 * distributed under the License is distributed on an "AS IS" BASIS,
013 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
014 * See the License for the specific language governing permissions and
015 * limitations under the License.
016 */
017
018package org.apache.commons.math4.ml.neuralnet.sofm;
019
020/**
021 * Provides the network neighbourhood's size as a function of the
022 * number of calls already performed during the learning task.
023 * The "neighbourhood" is the set of neurons that can be reached
024 * by traversing at most the number of links returned by this
025 * function.
026 *
027 * @since 3.3
028 */
029public interface NeighbourhoodSizeFunction {
030    /**
031     * Computes the neighbourhood size at the current call.
032     *
033     * @param numCall Current step of the training task.
034     * @return the value of the function at {@code numCall}.
035     */
036    int value(long numCall);
037}