Hi Lydia,
Since matrix multiplication is O(n^3), I would assume that it would simply
take 1000 times longer than the multiplication of the 100 x 100 matrix.
Have you waited so long to see whether it completes or is there another
problem?
Cheers,
Till
On Mon, Jan 25, 2016 at 2:13 PM, Lydia Ickler <ickle...@googlemail.com>
wrote:
> Hi,
>
> I want do a simple MatrixMultiplication and use the following code (see
> bottom).
> For matrices 50x50 or 100x100 it is no problem. But already with matrices
> of 1000x1000 it would not work anymore and gets stuck in the joining part.
> What am I doing wrong?
>
> Best regards,
> Lydia
>
> package de.tuberlin.dima.aim3.assignment3;
>
> import org.apache.flink.api.common.functions.MapFunction;
> import org.apache.flink.api.java.ExecutionEnvironment;
> import org.apache.flink.api.java.io.CsvReader;
> import org.apache.flink.api.java.operators.DataSource;
> import org.apache.flink.api.java.operators.GroupReduceOperator;
> import org.apache.flink.api.java.tuple.Tuple2;
> import org.apache.flink.api.java.tuple.Tuple3;
> import org.apache.flink.api.java.DataSet;
>
>
> public class MatrixMultiplication {
>
> static String input = null;
> static String output = null;
>
> public void run() throws Exception {
> ExecutionEnvironment env =
> ExecutionEnvironment.getExecutionEnvironment();
>
> DataSet<Tuple3<Integer, Integer, Double>> matrixA = readMatrix(env,
> input);
>
> matrixA.join(matrixA).where(1).equalTo(0)
> .map(new ProjectJoinResultMapper()).groupBy(0,
> 1).sum(2).writeAsCsv(output);
>
>
> env.execute();
> }
>
>
>
> public static DataSource<Tuple3<Integer, Integer, Double>>
> readMatrix(ExecutionEnvironment env,
> String filePath) {
> CsvReader csvReader = env.readCsvFile(filePath);
> csvReader.fieldDelimiter(',');
> csvReader.includeFields("fttt");
> return csvReader.types(Integer.class, Integer.class, Double.class);
> }
>
> public static final class ProjectJoinResultMapper implements
> MapFunction<Tuple2<Tuple3<Integer, Integer, Double>,
> Tuple3<Integer, Integer, Double>>,
> Tuple3<Integer, Integer, Double>> {
> @Override
> public Tuple3<Integer, Integer, Double> map(
> Tuple2<Tuple3<Integer, Integer, Double>, Tuple3<Integer, Integer,
> Double>> value)
> throws Exception {
> Integer row = value.f0.f0;
> Integer column = value.f1.f1;
> Double product = value.f0.f2 * value.f1.f2;
> return new Tuple3<Integer, Integer, Double>(row, column, product);
> }
> }
>
>
> public static void main(String[] args) throws Exception {
> if(args.length<2){
> System.err.println("Usage: MatrixMultiplication <input path> <result
> path>");
> System.exit(0);
> }
> input = args[0];
> output = args[1];
> new MatrixMultiplication().run();
> }
>
> }
>
>
>
