org.deeplearning4j.util.CapsuleUtils Maven / Gradle / Ivy
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* * terms of the Apache License, Version 2.0 which is available at
* * https://www.apache.org/licenses/LICENSE-2.0.
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* * information regarding copyright ownership.
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* * SPDX-License-Identifier: Apache-2.0
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package org.deeplearning4j.util;
import org.nd4j.autodiff.samediff.SDVariable;
import org.nd4j.autodiff.samediff.SameDiff;
public class CapsuleUtils {
/**
* Compute the squash operation used in CapsNet
* The formula is (||s||^2 / (1 + ||s||^2)) * (s / ||s||).
* Canceling one ||s|| gives ||s||*s/((1 + ||s||^2)
*
* @param SD The SameDiff environment
* @param x The variable to squash
* @return squash(x)
*/
public static SDVariable squash(SameDiff SD, SDVariable x, int dim){
SDVariable squaredNorm = SD.math.square(x).sum(true, dim);
SDVariable scale = SD.math.sqrt(squaredNorm.plus(1e-5));
return x.times(squaredNorm).div(squaredNorm.plus(1.0).times(scale));
}
}