org.apache.sysml.runtime.compress.UncompressedBitmap.java Source code

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Here is the source code for org.apache.sysml.runtime.compress.UncompressedBitmap.java

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/*
 * 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.sysml.runtime.compress;

import java.util.Arrays;

import org.apache.commons.lang.ArrayUtils;
import org.apache.sysml.runtime.compress.utils.DblArrayIntListHashMap;
import org.apache.sysml.runtime.compress.utils.DoubleIntListHashMap;
import org.apache.sysml.runtime.compress.utils.DblArrayIntListHashMap.DArrayIListEntry;
import org.apache.sysml.runtime.compress.utils.DoubleIntListHashMap.DIListEntry;
import org.apache.sysml.runtime.compress.utils.IntArrayList;
import org.apache.sysml.runtime.util.SortUtils;

/** 
 * Uncompressed representation of one or more columns in bitmap format. 
 * 
 */
public final class UncompressedBitmap {
    private final int _numCols;

    /** Distinct values that appear in the column. Linearized as value groups <v11 v12> <v21 v22>.*/
    private double[] _values;

    /** Bitmaps (as lists of offsets) for each of the values. */
    private IntArrayList[] _offsetsLists;

    public UncompressedBitmap(DblArrayIntListHashMap distinctVals, int numColumns) {
        // added for one pass bitmap construction
        // Convert inputs to arrays
        int numVals = distinctVals.size();
        _values = new double[numVals * numColumns];
        _offsetsLists = new IntArrayList[numVals];
        int bitmapIx = 0;
        for (DArrayIListEntry val : distinctVals.extractValues()) {
            System.arraycopy(val.key.getData(), 0, _values, bitmapIx * numColumns, numColumns);
            _offsetsLists[bitmapIx++] = val.value;
        }
        _numCols = numColumns;
    }

    public UncompressedBitmap(DoubleIntListHashMap distinctVals) {
        // added for one pass bitmap construction
        // Convert inputs to arrays
        int numVals = distinctVals.size();
        _values = new double[numVals];
        _offsetsLists = new IntArrayList[numVals];
        int bitmapIx = 0;
        for (DIListEntry val : distinctVals.extractValues()) {
            _values[bitmapIx] = val.key;
            _offsetsLists[bitmapIx++] = val.value;
        }
        _numCols = 1;
    }

    public int getNumColumns() {
        return _numCols;
    }

    /** 
     * Get all values without unnecessary allocations and copies.
     * 
     * @return dictionary of value tuples
     */
    public double[] getValues() {
        return _values;
    }

    /**
     * Obtain tuple of column values associated with index.
     * 
     * @param ix   index of a particular distinct value
     * @return the tuple of column values associated with the specified index
     */
    public double[] getValues(int ix) {
        return Arrays.copyOfRange(_values, ix * _numCols, (ix + 1) * _numCols);
    }

    /**
     * Obtain number of distinct values in the column.
     * 
     * @return number of distinct values in the column; this number is also the
     *         number of bitmaps, since there is one bitmap per value
     */
    public int getNumValues() {
        return _values.length / _numCols;
    }

    public IntArrayList getOffsetsList(int ix) {
        return _offsetsLists[ix];
    }

    public long getNumOffsets() {
        long ret = 0;
        for (IntArrayList offlist : _offsetsLists)
            ret += offlist.size();
        return ret;
    }

    public int getNumOffsets(int ix) {
        return _offsetsLists[ix].size();
    }

    public void sortValuesByFrequency() {
        int numVals = getNumValues();
        int numCols = getNumColumns();

        double[] freq = new double[numVals];
        int[] pos = new int[numVals];

        //populate the temporary arrays
        for (int i = 0; i < numVals; i++) {
            freq[i] = getNumOffsets(i);
            pos[i] = i;
        }

        //sort ascending and reverse (descending)
        SortUtils.sortByValue(0, numVals, freq, pos);
        ArrayUtils.reverse(pos);

        //create new value and offset list arrays
        double[] lvalues = new double[numVals * numCols];
        IntArrayList[] loffsets = new IntArrayList[numVals];
        for (int i = 0; i < numVals; i++) {
            System.arraycopy(_values, pos[i] * numCols, lvalues, i * numCols, numCols);
            loffsets[i] = _offsetsLists[pos[i]];
        }
        _values = lvalues;
        _offsetsLists = loffsets;
    }
}