import java.nio.channels.FileChannel;
import java.nio.ByteBuffer;
import java.nio.ByteOrder;
import static java.nio.channels.FileChannel.MapMode.READ_ONLY;
import static java.nio.ByteOrder.LITTLE_ENDIAN;

---

        FileChannel fileChannel = new FileInputStream("gaussian.dat").getChannel();
        fileChannel.map(READ_ONLY, 0, fileChannel.size()).order(LITTLE_ENDIAN).asDoubleBuffer().get(data);

        while (end < data.length) {
            pool.submit(new Partitioner(data, partitions, bucketCount, begin, end));
            begin += batchSize; end += batchSize;
        }
        pool.submit(new Partitioner(data, partitions, bucketCount,
                begin, data.length));