| /* |
| * 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.datasketches.hive.tuple; |
| |
| import org.apache.datasketches.hive.common.BytesWritableHelper; |
| import org.apache.datasketches.quantiles.DoublesSketch; |
| import org.apache.datasketches.quantiles.DoublesSketchBuilder; |
| import org.apache.datasketches.quantiles.UpdateDoublesSketch; |
| import org.apache.datasketches.tuple.ArrayOfDoublesSketch; |
| import org.apache.datasketches.tuple.ArrayOfDoublesSketchIterator; |
| import org.apache.datasketches.tuple.ArrayOfDoublesSketches; |
| import org.apache.hadoop.hive.ql.exec.Description; |
| import org.apache.hadoop.hive.ql.exec.UDF; |
| import org.apache.hadoop.io.BytesWritable; |
| |
| @Description( |
| name = "ArrayOfDoublesSketchToQuantilesSketch", |
| value = "_FUNC_(sketch, column, k)", |
| extended = "Returns a quanitles DoublesSketch constructed from a given" |
| + " column of double values from a given ArrayOfDoublesSketch using parameter k" |
| + " that determines the accuracy and size of the quantiles sketch." |
| + " The column number is optional (the default is 1)." |
| + " The parameter k is optional (the default is defined in the sketch library)." |
| + " The result is a serialized quantiles sketch.") |
| @SuppressWarnings("javadoc") |
| public class ArrayOfDoublesSketchToQuantilesSketchUDF extends UDF { |
| |
| /** |
| * Convert the first column from a given ArrayOfDoublesSketch to a quantiles DoublesSketch |
| * using the default parameter k. |
| * @param serializedSketch ArrayOfDoublesSketch in as serialized binary |
| * @return serialized DoublesSketch |
| */ |
| public BytesWritable evaluate(final BytesWritable serializedSketch) { |
| return evaluate(serializedSketch, 1, 0); |
| } |
| |
| /** |
| * Convert a given column from a given ArrayOfDoublesSketch to a quantiles DoublesSketch |
| * using the default parameter k. |
| * @param serializedSketch ArrayOfDoublesSketch in as serialized binary |
| * @param column 1-based column number |
| * @return serialized DoublesSketch |
| */ |
| public BytesWritable evaluate(final BytesWritable serializedSketch, final int column) { |
| return evaluate(serializedSketch, column, 0); |
| } |
| |
| /** |
| * Convert a given column from a given ArrayOfDoublesSketch to a quantiles DoublesSketch |
| * @param serializedSketch ArrayOfDoublesSketch in as serialized binary |
| * @param column 1-based column number |
| * @param k parameter that determines the accuracy and size of the quantiles sketch |
| * @return serialized DoublesSketch |
| */ |
| public BytesWritable evaluate(final BytesWritable serializedSketch, final int column, |
| final int k) { |
| if (serializedSketch == null) { return null; } |
| final ArrayOfDoublesSketch sketch = ArrayOfDoublesSketches.wrapSketch( |
| BytesWritableHelper.wrapAsMemory(serializedSketch)); |
| if (column < 1) { |
| throw new IllegalArgumentException("Column number must be greater than zero. Received: " |
| + column); |
| } |
| if (column > sketch.getNumValues()) { |
| throw new IllegalArgumentException("Column number " + column |
| + " is out of range. The given sketch has " |
| + sketch.getNumValues() + " columns"); |
| } |
| final DoublesSketchBuilder builder = DoublesSketch.builder(); |
| if (k > 0) { |
| builder.setK(k); |
| } |
| final UpdateDoublesSketch qs = builder.build(); |
| final ArrayOfDoublesSketchIterator it = sketch.iterator(); |
| while (it.next()) { |
| qs.update(it.getValues()[column - 1]); |
| } |
| return new BytesWritable(qs.compact().toByteArray()); |
| } |
| |
| } |