Example usage for com.google.common.math Quantiles scale

Introduction

In this page you can find the example usage for com.google.common.math Quantiles scale.

Prototype

public static Scale scale(int scale) 

Source Link

Document

Specifies the computation of q-quantiles.

Usage

From source file:org.apache.aurora.scheduler.sla.SlaUtil.java

/**
 * Reports the percentile value from the continuous distribution described by a given list of
 * samples.//from  www . j a va 2  s .com
 *
 * Example: [30, 60, 70, 90], the 50 percentile is 65.0 (i.e. larger values cover 50% of the PDF
 * (Probability Density Function)).
 * Example: [30, 60, 70, 90], the 75 percentile is 52.5 (i.e. larger values cover 75% of the PDF).
 * Example: [30, 60, 70, 90], the 90 percentile is 39.0 (i.e. larger values cover 85% of the PDF).
 * Example: [30, 60, 70, 90], the 99 percentile is 30.9 (i.e. larger values cover 95% of the PDF).
 *
 * @param list List to calculate percentile for.
 * @param percentile Percentile value to apply.
 * @return Element at the given percentile.
 */
static Number percentile(List<Long> list, double percentile) {
    if (list.isEmpty()) {
        return 0.0;
    }

    // index should be a full integer. use quantile scale to allow reporting of percentile values
    // such as p99.9.
    double percentileCopy = percentile;
    int quantileScale = 100;
    while ((percentileCopy - Math.floor(percentileCopy)) > 0) {
        quantileScale *= 10;
        percentileCopy *= 10;
    }

    return Quantiles.scale(quantileScale).index((int) Math.floor(quantileScale - percentileCopy)).compute(list);
}

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