// Copyright Yahoo. 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.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.Function;
/**
* The cell_cast tensor function creates a new tensor with the specified cell value type.
*
* @author lesters
*/
public class CellCast extends PrimitiveTensorFunction {
private final TensorFunction argument;
private final TensorType.Value valueType;
public CellCast(TensorFunction argument, TensorType.Value valueType) {
Objects.requireNonNull(argument, "The argument tensor cannot be null");
Objects.requireNonNull(valueType, "The value type cannot be null");
this.argument = argument;
this.valueType = valueType;
}
@Override
public List> arguments() { return Collections.singletonList(argument); }
@Override
public TensorFunction withArguments(List> arguments) {
if ( arguments.size() != 1)
throw new IllegalArgumentException("CellCast must have 1 argument, got " + arguments.size());
return new CellCast<>(arguments.get(0), valueType);
}
@Override
public PrimitiveTensorFunction toPrimitive() {
return new CellCast<>(argument.toPrimitive(), valueType);
}
@Override
public TensorType type(TypeContext context) {
return TypeResolver.cell_cast(argument.type(context), valueType);
}
@Override
public Tensor evaluate(EvaluationContext context) {
Tensor tensor = argument.evaluate(context);
if (tensor.type().valueType() == valueType) {
return tensor;
}
TensorType type = TypeResolver.cell_cast(tensor.type(), valueType);
return cast(tensor, type);
}
private Tensor cast(Tensor tensor, TensorType type) {
TensorType.Value fromValueType = tensor.type().valueType();
switch (fromValueType) {
case DOUBLE:
return castFromDouble(tensor, type);
case FLOAT:
case BFLOAT16:
case INT8:
return castFromSomeFloat(tensor, type);
default:
throw new IllegalStateException("Unexpected value type " + fromValueType);
}
}
private Tensor castFromDouble(Tensor tensor, TensorType type) {
Tensor.Builder builder = Tensor.Builder.of(type);
var restrict = selectRestrict(type.valueType());
for (Iterator i = tensor.cellIterator(); i.hasNext(); ) {
Tensor.Cell cell = i.next();
builder.cell(cell.getKey(), restrict.apply((float)cell.getDoubleValue()));
}
return builder.build();
}
private Tensor castFromSomeFloat(Tensor tensor, TensorType type) {
Tensor.Builder builder = Tensor.Builder.of(type);
var restrict = selectRestrict(type.valueType());
for (Iterator i = tensor.cellIterator(); i.hasNext(); ) {
Tensor.Cell cell = i.next();
builder.cell(cell.getKey(), restrict.apply(cell.getFloatValue()));
}
return builder.build();
}
static private Function selectRestrict(TensorType.Value toValueType) {
switch (toValueType) {
case BFLOAT16:
return val -> Float.intBitsToFloat(Float.floatToRawIntBits(val) & ~0xffff);
case INT8:
return val -> (float)val.byteValue();
default:
return val -> val;
}
}
@Override
public String toString(ToStringContext context) {
return "cell_cast(" + argument.toString(context) + ", " + valueType + ")";
}
@Override
public int hashCode() { return Objects.hash("cellcast", argument, valueType); }
}