io.seldon.prediction.VariationPredictionStrategy.java Source code

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Here is the source code for io.seldon.prediction.VariationPredictionStrategy.java

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/*
 * Seldon -- open source prediction engine
 * =======================================
 * Copyright 2011-2015 Seldon Technologies Ltd and Rummble Ltd (http://www.seldon.io/)
 *
 **********************************************************************************************
 *
 * 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 io.seldon.prediction;

import java.math.BigDecimal;
import java.util.LinkedHashMap;
import java.util.List;
import java.util.Map;

import org.apache.commons.lang.math.NumberRange;
import org.apache.commons.lang.math.Range;

import scala.concurrent.forkjoin.ThreadLocalRandom;

public class VariationPredictionStrategy implements PredictionStrategy {

    private final Map<Range, SimplePredictionStrategy> strategyMap;

    public VariationPredictionStrategy(Map<Range, SimplePredictionStrategy> strategyMap) {
        this.strategyMap = strategyMap;
    }

    @Override
    public List<PredictionAlgorithmStrategy> getAlgorithms() {
        return sample().getAlgorithms();
    }

    @Override
    public List<FeatureTransformerStrategy> getFeatureTansformers() {
        return sample().getFeatureTansformers();
    }

    public SimplePredictionStrategy sample() {
        Integer hash = ThreadLocalRandom.current().nextInt();
        int sample = Math.abs(hash % 100) + 1;
        BigDecimal sampleDec = BigDecimal.valueOf(sample).divide(BigDecimal.valueOf(100));
        for (Range range : strategyMap.keySet()) {
            if (range.containsNumber(sampleDec)) {
                return strategyMap.get(range);
            }
        }
        return null;
    }

    @Override
    public SimplePredictionStrategy configure() {
        return sample();
    }

    public static VariationPredictionStrategy build(List<Variation> variations) {
        Map<Range, SimplePredictionStrategy> strategyMap = new LinkedHashMap<>();
        BigDecimal ratioTotal = BigDecimal.ZERO;
        for (Variation var : variations) {
            ratioTotal = ratioTotal.add(var.ratio);
        }
        BigDecimal currentMax = BigDecimal.ZERO;
        for (Variation var : variations) {
            NumberRange range = new NumberRange(currentMax,
                    currentMax.add(var.ratio.divide(ratioTotal, 5, BigDecimal.ROUND_UP)));
            strategyMap.put(range, var.variationStrategy);
            currentMax = currentMax.add(var.ratio);
        }
        return new VariationPredictionStrategy(strategyMap);
    }

    public static class Variation {
        public final SimplePredictionStrategy variationStrategy;
        public final BigDecimal ratio;

        public Variation(SimplePredictionStrategy variationStrategy, BigDecimal ratio) {
            this.variationStrategy = variationStrategy;
            this.ratio = ratio;
        }
    }

}