src/main/java/org/apache/sysds/runtime/instructions/spark/functions/FilterDiagMatrixBlocksFunction.java

/*
 * 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
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package org.apache.sysds.runtime.instructions.spark.functions;

import org.apache.spark.api.java.function.Function;
import org.apache.sysds.runtime.matrix.data.MatrixBlock;
import org.apache.sysds.runtime.matrix.data.MatrixIndexes;
import scala.Tuple2;

public class FilterDiagMatrixBlocksFunction implements Function<Tuple2<MatrixIndexes,MatrixBlock>, Boolean>
{
	
	private static final long serialVersionUID = 685221977882289849L;
	
	@Override
	public Boolean call(Tuple2<MatrixIndexes, MatrixBlock> arg0)
		throws Exception 
	{
		//returns true for matrix blocks on matrix diagonal
		MatrixIndexes ix = arg0._1();
		return (ix.getRowIndex() == ix.getColumnIndex());
	}
	

}