public void setup(Context context) throws IOException, InterruptedException {
Configuration conf = context.getConfiguration();
System.out.println("tid: " + conf.get("mapred.task.id"));
fs = FileSystem.get(conf);
int blockSize = conf.getInt("matmul.block.size", 1);
numRowsInBlock = conf.getInt("matmul.num.rows.in.block", 1);
numColsInBlock = blockSize / numRowsInBlock;
useCache = conf.getBoolean("matmul.useCache", true);
}
public void map(final String[] indices, final TrackedSegments trSegs, final Context context)
throws IOException, InterruptedException {
System.out.println("working on: " + indices[0] + "\t" + indices[1]);
int AIdx = 0, BIdx = 0;
if (indices[0].contains("A")) {
AIdx = 0;
BIdx = 1;
} else {
AIdx = 1;
BIdx = 0;
}
Segment[] segments = trSegs.segments;
Segment segA = segments[AIdx];
Segment segB = segments[BIdx];
FSDataInputStream in;
DataInputStream dataIn;
Configuration conf = context.getConfiguration();
long versionId = conf.getLong("matmul.versionId", 0);
long start, end;
// read the B segment into memory
int size = numRowsInBlock * numColsInBlock;
double[] matrixBlockB = new double[size];
start = System.currentTimeMillis();
if (useCache) {
in = fs.openCachedReadOnly(segB.getPath(), versionId);
} else {
in = fs.open(segB.getPath());
}
in.seek(segB.getOffset());
// dataIn = new DataInputStream(new BufferedInputStream(in));
dataIn = new DataInputStream(in);
for (int i = 0; i < size; ++i) {
matrixBlockB[i] = dataIn.readDouble();
}
in.close();
end = System.currentTimeMillis();
System.out.println("matrixB read time: " + (end - start) + " ms");
System.out.println(
"matrixB read bandwidth: " + size * 8 / (end - start) / 1000 + " MBytes/s");
// prepare for context write
String CRowId = indices[AIdx].split("_")[2];
String CColId = indices[BIdx].split("_")[2];
String outName = "C_" + CRowId + "_" + CColId;
Path outPath = new Path(FileOutputFormat.getWorkOutputPath(context), outName);
BufferedOutputStream out = new BufferedOutputStream(fs.create(outPath));
DataOutputStream dataOut = new DataOutputStream(out);
// do the multiplication
if (useCache) {
in = fs.openCachedReadOnly(segA.getPath(), versionId);
} else {
in = fs.open(segA.getPath());
}
in.seek(segA.getOffset());
// dataIn = new DataInputStream(new BufferedInputStream(in));
dataIn = new DataInputStream(in);
long readTime = 0, calcTime = 0;
for (int i = 0; i < numRowsInBlock; ++i) {
double[] rowA = new double[numColsInBlock];
start = System.currentTimeMillis();
for (int j = 0; j < numColsInBlock; ++j) {
rowA[j] = dataIn.readDouble();
}
end = System.currentTimeMillis();
readTime += end - start;
// caclulate out[i, :]
start = System.currentTimeMillis();
for (int j = 0; j < numRowsInBlock; ++j) {
// calculate out [i, j]
double sum = 0;
for (int k = 0; k < numColsInBlock; ++k) {
sum += rowA[k] * matrixBlockB[j * numColsInBlock + k];
}
dataOut.writeDouble(sum);
}
end = System.currentTimeMillis();
calcTime += end - start;
}
in.close();
dataOut.close();
System.out.println("matrixA read time: " + readTime + " ms");
System.out.println("matrixA read bandwidth: " + size * 8 / readTime / 1000 + " MBytes/s");
System.out.println("multiplication calc time: " + calcTime + " ms");
}