org.datavec.local.transforms.misc.WritablesToNDArrayFunction Maven / Gradle / Ivy
/*******************************************************************************
* Copyright (c) 2015-2018 Skymind, Inc.
*
* This program and the accompanying materials are made available under the
* terms of the Apache License, Version 2.0 which is available at
* https://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.
*
* SPDX-License-Identifier: Apache-2.0
******************************************************************************/
package org.datavec.local.transforms.misc;
import org.datavec.api.writable.NDArrayWritable;
import org.datavec.api.writable.Writable;
import org.nd4j.linalg.api.ndarray.INDArray;
import org.nd4j.linalg.factory.Nd4j;
import org.nd4j.linalg.function.Function;
import org.nd4j.linalg.indexing.NDArrayIndex;
import java.util.Arrays;
import java.util.List;
/**
* Function for converting lists of Writables to a single
* NDArray row vector. Necessary for creating and saving a
* dense matrix representation of raw data.
*
* @author [email protected]
*/
public class WritablesToNDArrayFunction implements Function, INDArray> {
@Override
public INDArray apply(List c) {
int length = 0;
for (Writable w : c) {
if (w instanceof NDArrayWritable) {
INDArray a = ((NDArrayWritable) w).get();
if (a.isRowVector()) {
length += a.columns();
} else {
throw new UnsupportedOperationException("NDArrayWritable is not a row vector."
+ " Can only concat row vectors with other writables. Shape: "
+ Arrays.toString(a.shape()));
}
} else {
length++;
}
}
INDArray arr = Nd4j.zeros(1, length);
int idx = 0;
for (Writable w : c) {
if (w instanceof NDArrayWritable) {
INDArray subArr = ((NDArrayWritable) w).get();
int subLength = subArr.columns();
arr.get(NDArrayIndex.point(0), NDArrayIndex.interval(idx, idx + subLength)).assign(subArr);
idx += subLength;
} else {
arr.putScalar(idx++, w.toDouble());
}
}
return arr;
}
}