org.apache.hadoop.hive.ql.udf.UDFExp Maven / Gradle / Ivy
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* Licensed to the Apache Software Foundation (ASF) under one
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* distributed with this work for additional information
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* to you under the Apache License, Version 2.0 (the
* "License"); you may not use this file except in compliance
* with the License. You may obtain a copy of the License at
*
* http://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,
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* See the License for the specific language governing permissions and
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*/
package org.apache.hadoop.hive.ql.udf;
import org.apache.hadoop.hive.ql.exec.Description;
import org.apache.hadoop.hive.ql.exec.vector.VectorizedExpressions;
import org.apache.hadoop.hive.ql.exec.vector.expressions.gen.FuncExpDoubleToDouble;
import org.apache.hadoop.hive.ql.exec.vector.expressions.gen.FuncExpLongToDouble;
import org.apache.hadoop.hive.serde2.io.DoubleWritable;
/**
* UDFExp.
*/
@Description(name = "exp",
value = "_FUNC_(x) - Returns e to the power of x",
extended = "Example:\n "
+ " > SELECT _FUNC_(0) FROM src LIMIT 1;\n"
+ " 1"
)
@VectorizedExpressions({FuncExpDoubleToDouble.class, FuncExpLongToDouble.class})
public class UDFExp extends UDFMath {
private final DoubleWritable result = new DoubleWritable();
/**
* Raise e (the base of natural logarithm) to the power of a.
*/
@Override
protected DoubleWritable doEvaluate(DoubleWritable a) {
result.set(Math.exp(a.get()));
return result;
}
}