com.yahoo.tensor.functions.Softmax Maven / Gradle / Ivy
// Copyright Vespa.ai. Licensed under the terms of the Apache 2.0 license. See LICENSE in the project root.
package com.yahoo.tensor.functions;
import com.yahoo.tensor.TensorType;
import com.yahoo.tensor.evaluation.Name;
import java.util.List;
import java.util.Objects;
/**
* @author bratseth
*/
public class Softmax extends CompositeTensorFunction {
private final TensorFunction argument;
private final String dimension;
public Softmax(TensorFunction argument, String dimension) {
this.argument = argument;
this.dimension = dimension;
}
public static TensorType outputType(TensorType inputType, String dimension) {
return Reduce.outputType(inputType, List.of(dimension));
}
@Override
public List> arguments() { return List.of(argument); }
@Override
public TensorFunction withArguments(List> arguments) {
if ( arguments.size() != 1)
throw new IllegalArgumentException("Softmax must have 1 argument, got " + arguments.size());
return new Softmax<>(arguments.get(0), dimension);
}
@Override
public PrimitiveTensorFunction toPrimitive() {
TensorFunction primitiveArgument = argument.toPrimitive();
return new Join<>(new Map<>(primitiveArgument, ScalarFunctions.exp()),
new Reduce<>(new Map<>(primitiveArgument, ScalarFunctions.exp()),
Reduce.Aggregator.sum,
dimension),
ScalarFunctions.divide());
}
@Override
public String toString(ToStringContext context) {
return "softmax(" + argument.toString(context) + ", " + context.resolveBinding(dimension) + ")";
}
@Override
public int hashCode() { return Objects.hash("softmax", argument, dimension); }
}