/*
* 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.mahout.h2obindings.ops;
import org.apache.mahout.h2obindings.drm.H2ODrm;
import water.MRTask;
import water.fvec.Frame;
import water.fvec.Vec;
import water.fvec.Chunk;
import water.fvec.NewChunk;
/**
* Element-wise DRM-DRM operations
*/
public class AewB {
/**
* Perform element-wise operation on two DRMs to create a new DRM.
*
* @param drmA DRM representing matrix A.
* @param drmB DRM representing matrix B.
* @param op Element-wise operator encoded as a String.
* @return new DRM containing A (element-wise) B.
*/
public static H2ODrm exec(H2ODrm drmA, H2ODrm drmB, final String op) {
final Frame A = drmA.frame;
final Frame B = drmB.frame;
Vec keys = drmA.keys;
int AewB_cols = A.numCols();
// AewB is written into ncs[] with an MRTask on A, and therefore will
// be similarly partitioned as A.
//
// B may or may not be similarly partitioned as A, but must have the
// same dimensions of A.
Frame AewB = new MRTask() {
private double opfn(String op, double a, double b) {
if (a == 0.0 && b == 0.0) {
return 0.0;
}
if (op.equals("+")) {
return a + b;
} else if (op.equals("-")) {
return a - b;
} else if (op.equals("*")) {
return a * b;
} else if (op.equals("/")) {
return a / b;
}
return 0.0;
}
@Override
public void map(Chunk chks[], NewChunk ncs[]) {
int chunkSize = chks[0].len();
Vec B_vecs[] = B.vecs();
long start = chks[0].start();
for (int c = 0; c < chks.length; c++) {
for (int r = 0; r < chunkSize; r++) {
ncs[c].addNum(opfn(op, chks[c].at0(r), B_vecs[c].at(start + r)));
}
}
}
}.doAll(AewB_cols, A).outputFrame(null, null);
// Carry forward labels of A blindly into ABt
return new H2ODrm(AewB, keys);
}
}