org.apache.sysml.runtime.transform.encode.Encoder.java Source code

Introduction

Here is the source code for org.apache.sysml.runtime.transform.encode.Encoder.java

Source

/*
 * 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.transform.encode;

import java.io.Serializable;
import java.util.Arrays;

import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;
import org.apache.sysml.runtime.matrix.data.FrameBlock;
import org.apache.sysml.runtime.matrix.data.MatrixBlock;
import org.apache.sysml.runtime.util.UtilFunctions;
import org.apache.wink.json4j.JSONArray;

/**
 * Base class for all transform encoders providing both a row and block
 * interface for decoding frames to matrices.
 * 
 */
public abstract class Encoder implements Serializable {
    private static final long serialVersionUID = 2299156350718979064L;
    protected static final Log LOG = LogFactory.getLog(Encoder.class.getName());

    protected int _clen = -1;
    protected int[] _colList = null;

    protected Encoder(int[] colList, int clen) {
        _colList = colList;
        _clen = clen;
    }

    public int[] getColList() {
        return _colList;
    }

    public void setColList(int[] colList) {
        _colList = colList;
    }

    public int getNumCols() {
        return _clen;
    }

    public int initColList(JSONArray attrs) {
        _colList = new int[attrs.size()];
        for (int i = 0; i < _colList.length; i++)
            _colList[i] = UtilFunctions.toInt(attrs.get(i));
        return _colList.length;
    }

    public int initColList(int[] colList) {
        _colList = colList;
        return _colList.length;
    }

    /**
     * Indicates if this encoder is applicable, i.e, if there is at 
     * least one column to encode. 
     * 
     * @return true if at least one column to encode
     */
    public boolean isApplicable() {
        return (_colList != null && _colList.length > 0);
    }

    /**
     * Indicates if this encoder is applicable for the given column ID,
     * i.e., if it is subject to this transformation.
     * 
     * @param colID column ID
     * @return true if encoder is applicable for given column
     */
    public int isApplicable(int colID) {
        if (_colList == null)
            return -1;
        int idx = Arrays.binarySearch(_colList, colID);
        return (idx >= 0 ? idx : -1);
    }

    /**
     * Block encode: build and apply (transform encode).
     * 
     * @param in input frame block
     * @param out output matrix block
     * @return output matrix block
     */
    public abstract MatrixBlock encode(FrameBlock in, MatrixBlock out);

    /**
     * Build the transform meta data for the given block input. This call modifies
     * and keeps meta data as encoder state.
     * 
     * @param in input frame block
     */
    public abstract void build(FrameBlock in);

    /**
     * Encode input data blockwise according to existing transform meta
     * data (transform apply).
     * 
     * @param in input frame block
     * @param out output matrix block
     * @return output matrix block
     */
    public abstract MatrixBlock apply(FrameBlock in, MatrixBlock out);

    /**
     * Construct a frame block out of the transform meta data.
     * 
     * @param out output frame block
     * @return output frame block?
     */
    public abstract FrameBlock getMetaData(FrameBlock out);

    /**
     * Sets up the required meta data for a subsequent call to apply.
     * 
     * @param meta frame block
     */
    public abstract void initMetaData(FrameBlock meta);

    /**
     * Obtain the column mapping of encoded frames based on the passed
     * meta data frame.
     * 
     * @param meta meta data frame block
     * @param out output matrix
     * @return matrix with column mapping (one row per attribute)
     */
    public MatrixBlock getColMapping(FrameBlock meta, MatrixBlock out) {
        //default: do nothing
        return out;
    }
}