| /** |
| * 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.apex.malhar.contrib.r; |
| |
| import java.io.IOException; |
| import java.util.ArrayList; |
| import java.util.List; |
| |
| import org.rosuda.REngine.REngineException; |
| import org.slf4j.Logger; |
| import org.slf4j.LoggerFactory; |
| |
| import com.datatorrent.api.Context; |
| import com.datatorrent.api.DefaultInputPort; |
| import com.datatorrent.api.DefaultOutputPort; |
| import com.datatorrent.api.annotation.OperatorAnnotation; |
| import com.datatorrent.api.annotation.OutputPortFieldAnnotation; |
| import com.datatorrent.common.util.BaseOperator; |
| import com.datatorrent.netlet.util.DTThrowable; |
| |
| /** |
| * This operator computes variance and standard deviation over incoming data using R functions <br> |
| * <br> |
| * <b>Input Port(s) : </b><br> |
| * <b>data : </b> Received data values on this input port. <br> |
| * <br> |
| * <b>Output Port(s) : </b> <br> |
| * <b>variance : </b>Variance value output port. <br> |
| * <b>standardDeviation : </b>Std deviation value output port. <br> |
| * <br> |
| * <b>StateFull : Yes</b>, value are aggregated over application window. <br> |
| * <b>Partitions : No</b>, no. <br> |
| * <br> |
| * |
| * @displayName R Standard Deviation |
| * @category Scripting |
| * @tags script, r |
| * @since 2.1.0 |
| */ |
| |
| @OperatorAnnotation(partitionable = false) |
| public class RStandardDeviation extends BaseOperator |
| { |
| |
| private List<Number> values = new ArrayList<Number>(); |
| REngineConnectable connectable; |
| |
| private static Logger log = LoggerFactory.getLogger(RStandardDeviation.class); |
| /** |
| * Input data port. |
| */ |
| public final transient DefaultInputPort<Number> data = new DefaultInputPort<Number>() |
| { |
| /** |
| * Computes sum and count with each tuple |
| */ |
| @Override |
| public void process(Number tuple) |
| { |
| values.add(tuple.doubleValue()); |
| |
| } |
| }; |
| |
| /** |
| * Variance output port |
| */ |
| @OutputPortFieldAnnotation(optional = true) |
| public final transient DefaultOutputPort<Number> variance = new DefaultOutputPort<Number>(); |
| |
| /** |
| * Standard deviation output port |
| */ |
| public final transient DefaultOutputPort<Number> standardDeviation = new DefaultOutputPort<Number>(); |
| |
| @Override |
| public void setup(Context.OperatorContext context) |
| { |
| super.setup(context); |
| try { |
| connectable = new REngineConnectable(); |
| connectable.connect(); |
| } catch (IOException ioe) { |
| log.error("Exception: ", ioe); |
| DTThrowable.rethrow(ioe); |
| } |
| } |
| |
| /* |
| * Stop the R engine |
| */ |
| @Override |
| public void teardown() |
| { |
| try { |
| connectable.disconnect(); |
| } catch (IOException ioe) { |
| log.error("Exception: ", ioe); |
| DTThrowable.rethrow(ioe); |
| } |
| } |
| |
| /* |
| * Calculates and emits the values of variance and standard deviation. Clears the vector at the end of the function. |
| * SO starts with new data in every application window. |
| */ |
| |
| @Override |
| public void endWindow() |
| { |
| if (values.size() == 0) { |
| return; |
| } |
| double[] vector = new double[values.size()]; |
| for (int i = 0; i < values.size(); i++) { |
| vector[i] = values.get(i).doubleValue(); |
| } |
| try { |
| connectable.getRengine().assign("values", vector); |
| } catch (REngineException e) { |
| log.error("Exception: ", e); |
| DTThrowable.rethrow(e); |
| } |
| |
| double rStandardDeviation = 0; |
| double rVariance = 0; |
| try { |
| rStandardDeviation = connectable.getRengine().parseAndEval("sd(values)").asDouble(); |
| rVariance = connectable.getRengine().parseAndEval("var(values)").asDouble(); |
| connectable.getRengine().parseAndEval("rm(list = setdiff(ls(), lsf.str()))"); |
| } catch (Exception e) { |
| log.error("Exception: ", e); |
| DTThrowable.rethrow(e); |
| } |
| |
| variance.emit(rVariance); |
| standardDeviation.emit(rStandardDeviation); |
| |
| values.clear(); |
| |
| } |
| } |