/*
* Licensed 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 com.facebook.presto.operator.aggregation;
import com.facebook.presto.spi.block.Block;
import com.facebook.presto.spi.type.StandardTypes;
import com.google.common.collect.ImmutableList;
import org.apache.commons.math3.stat.correlation.Covariance;
import java.util.List;
import static com.facebook.presto.block.BlockAssertions.createDoubleSequenceBlock;
import static com.facebook.presto.operator.aggregation.AggregationTestUtils.constructDoublePrimitiveArray;
public class TestDoubleCovariancePopAggregation
extends AbstractTestAggregationFunction
{
@Override
public Block[] getSequenceBlocks(int start, int length)
{
return new Block[]{createDoubleSequenceBlock(start, start + length), createDoubleSequenceBlock(start + 5, start + 5 + length)};
}
@Override
protected String getFunctionName()
{
return "covar_pop";
}
@Override
protected List<String> getFunctionParameterTypes()
{
return ImmutableList.of(StandardTypes.DOUBLE, StandardTypes.DOUBLE);
}
@Override
public Object getExpectedValue(int start, int length)
{
if (length <= 0) {
return null;
}
else if (length == 1) {
return 0.;
}
Covariance covariance = new Covariance();
return covariance.covariance(constructDoublePrimitiveArray(start + 5, length), constructDoublePrimitiveArray(start, length), false);
}
}