org.apache.hadoop.hive.ql.udf.UDFTanh 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,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * 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.FuncTanhDoubleToDouble;
import org.apache.hadoop.hive.ql.exec.vector.expressions.gen.FuncTanhLongToDouble;
import org.apache.hadoop.hive.serde2.io.DoubleWritable;

@Description(name = "tanh",
        value = "_FUNC_(x) - returns the hyperbolic tangent of x (x is in radians)",
        extended = "Example:\n "
                + "  > SELECT _FUNC_(0) FROM src LIMIT 1;\n"
                + "  1"
)
@VectorizedExpressions({FuncTanhLongToDouble.class, FuncTanhDoubleToDouble.class})
public class UDFTanh extends UDFMath{

    private final DoubleWritable result = new DoubleWritable();

    /**
     * Take Tangent hyperbolic of a
     */
    @Override
    protected DoubleWritable doEvaluate(DoubleWritable a) {
        result.set(StrictMath.tanh(a.get()));
        return result;
    }
}