org.apache.hadoop.hive.ql.udf.UDFSqrt Maven / Gradle / Ivy
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* Licensed to the Apache Software Foundation (ASF) under one
* or more contributor license agreements. See the NOTICE file
* distributed with this work for additional information
* regarding copyright ownership. The ASF licenses this file
* 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
* limitations under the License.
*/
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.FuncSqrtDoubleToDouble;
import org.apache.hadoop.hive.ql.exec.vector.expressions.gen.FuncSqrtLongToDouble;
import org.apache.hadoop.hive.serde2.io.DoubleWritable;
/**
* Implementation of the SQRT UDF found in many databases.
*/
@Description(name = "sqrt",
value = "_FUNC_(x) - returns the square root of x",
extended = "Example:\n "
+ " > SELECT _FUNC_(4) FROM src LIMIT 1;\n"
+ " 2")
@VectorizedExpressions({FuncSqrtLongToDouble.class, FuncSqrtDoubleToDouble.class})
public class UDFSqrt extends UDFMath {
private final DoubleWritable result = new DoubleWritable();
/**
* Return NULL for negative inputs; otherwise, return the square root.
*/
@Override
protected DoubleWritable doEvaluate(DoubleWritable a) {
if (a.get() < 0) {
return null;
} else {
result.set(Math.sqrt(a.get()));
return result;
}
}
}