gedi.util.math.stat.distributions.LfcDistribution.java Source code

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Here is the source code for gedi.util.math.stat.distributions.LfcDistribution.java

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/**
 * 
 *    Copyright 2017 Florian Erhard
 *
 *   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 gedi.util.math.stat.distributions;

import org.apache.commons.math3.special.Gamma;

import jdistlib.Beta;
import jdistlib.math.MathFunctions;

public class LfcDistribution {

    public static double ptol(double p) {
        return Math.log(p / (1 - p)) / Math.log(2);
    }

    public static double ltop(double l) {
        return Math.pow(2, l) / (1 + Math.pow(2, l));
    }

    public static double dlfc(double l, double a, double b, boolean log_p) {
        double r = (a * l + 1) * Math.log(2) - MathFunctions.lbeta(a, b) - (a + b) * Math.log(1 + Math.pow(2, l));
        if (!log_p)
            r = Math.exp(r);
        return r;
    }

    public static double plfc(double l, double a, double b, boolean lower_tail, boolean log_p) {
        return Beta.cumulative(ltop(l), a, b, lower_tail, log_p);
    }

    public static double qlfc(double alpha, double a, double b, boolean lower_tail, boolean log_p) {
        return Beta.quantile(alpha, a, b, lower_tail, log_p);
    }

    public static double mean(double a, double b) {
        return (Gamma.digamma(a) - Gamma.digamma(b)) / Math.log(2);
    }

    public static double var(double a, double b) {
        return (Gamma.trigamma(a) + Gamma.trigamma(b)) / Math.log(2) / Math.log(2);
    }

}