001    // --- BEGIN LICENSE BLOCK ---
002    /* 
003     * Copyright (c) 2009, Mikio L. Braun
004     * All rights reserved.
005     * 
006     * Redistribution and use in source and binary forms, with or without
007     * modification, are permitted provided that the following conditions are
008     * met:
009     * 
010     *     * Redistributions of source code must retain the above copyright
011     *       notice, this list of conditions and the following disclaimer.
012     * 
013     *     * Redistributions in binary form must reproduce the above
014     *       copyright notice, this list of conditions and the following
015     *       disclaimer in the documentation and/or other materials provided
016     *       with the distribution.
017     * 
018     *     * Neither the name of the Technische Universit?t Berlin nor the
019     *       names of its contributors may be used to endorse or promote
020     *       products derived from this software without specific prior
021     *       written permission.
022     * 
023     * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
024     * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
025     * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
026     * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
027     * HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
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029     * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
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031     * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
032     * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
033     * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
034     */
035    // --- END LICENSE BLOCK ---
036    
037    /*
038     * To change this template, choose Tools | Templates
039     * and open the template in the editor.
040     */
041    
042    package org.jblas.ranges;
043    
044    import org.jblas.*;
045    
046    /**
047     * Range which varies over pre-specified indices.
048     * 
049     * For example,
050     * <pre>
051     *     int[] indices = new int[] { 1, 1, 2, 3, 5, 8, 13 };
052     *     Range r = new IndicesRange(indices);</pre>
053     * ranges over the first few Fibonacci numbers.
054     */
055    public class IndicesRange implements Range {
056        private int[] indices;
057        private int counter;
058            
059        /** Initialize from integer array. */
060        public IndicesRange(int[] is) {
061            indices = is;
062        }
063        
064        public void init(int l, int u) {
065            counter = 0;
066        }
067        
068        /** 
069         * Initialize from DoubleMatrix. Entries are converted to integers
070         * by truncation.
071         */
072        public IndicesRange(DoubleMatrix is) {
073            this(is.toIntArray());
074        }
075        
076        public int length() {
077            return indices.length;
078        }
079        
080        public void next() {
081            counter++;
082        }
083        
084        public int index() {
085            return counter;
086        }
087    
088        public int value() {
089            return indices[counter];
090        }
091        
092        public boolean hasMore() {
093            return counter < indices.length;
094        }
095    }