// 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.Tensor;
import com.yahoo.tensor.TensorAddress;
import com.yahoo.tensor.TensorType;
import com.yahoo.tensor.TypeResolver;
import com.yahoo.tensor.evaluation.EvaluationContext;
import com.yahoo.tensor.evaluation.Name;
import com.yahoo.tensor.evaluation.TypeContext;
import java.util.Collections;
import java.util.Iterator;
import java.util.List;
import java.util.Objects;
import java.util.function.DoubleUnaryOperator;
/**
* The map tensor function produces a tensor where the given function is applied on each cell value.
*
* @author bratseth
*/
public class Map extends PrimitiveTensorFunction {
private final TensorFunction argument;
private final DoubleUnaryOperator mapper;
public Map(TensorFunction argument, DoubleUnaryOperator mapper) {
Objects.requireNonNull(argument, "The argument tensor cannot be null");
Objects.requireNonNull(mapper, "The argument function cannot be null");
this.argument = argument;
this.mapper = mapper;
}
public static TensorType outputType(TensorType inputType) {
return TypeResolver.map(inputType);
}
public TensorFunction argument() { return argument; }
public DoubleUnaryOperator mapper() { return mapper; }
@Override
public List> arguments() { return Collections.singletonList(argument); }
@Override
public TensorFunction withArguments(List> arguments) {
if ( arguments.size() != 1)
throw new IllegalArgumentException("Map must have 1 argument, got " + arguments.size());
return new Map<>(arguments.get(0), mapper);
}
@Override
public PrimitiveTensorFunction toPrimitive() {
return new Map<>(argument.toPrimitive(), mapper);
}
@Override
public TensorType type(TypeContext context) {
return outputType(argument.type(context));
}
@Override
public Tensor evaluate(EvaluationContext context) {
Tensor input = argument().evaluate(context);
Tensor.Builder builder = Tensor.Builder.of(outputType(input.type()));
for (Iterator i = input.cellIterator(); i.hasNext(); ) {
java.util.Map.Entry cell = i.next();
builder.cell(cell.getKey(), mapper.applyAsDouble(cell.getValue()));
}
return builder.build();
}
@Override
public String toString(ToStringContext context) {
return "map(" + argument.toString(context) + ", " + mapper + ")";
}
@Override
public int hashCode() { return Objects.hash("map", argument, mapper); }
}