Main.java Source code

Introduction

Here is the source code for Main.java

Source

//package com.java2s;
/*
 * Copyright bzewdu
 *
 *    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.
 */

public class Main {
    public static double stDist(final double v, final double t) {
        double sm = 0.5;
        double sign = 1.0;
        final double stepSize = t / 5000.0;
        if (t < 0.0) {
            sign = -1.0;
        } else if (t == 0.0 || Double.isInfinite(t)) {
            return sm;
        }
        for (double u = 0.0; u <= sign * t; u += stepSize) {
            sm += stepSize * student_tDen(v, u);
        }
        if (sign < 0.0) {
            sm = 0.5 - sm;
        } else {
            sm = 1.0 - sm;
        }
        if (sm < 0.0) {
            sm = 0.0;
        } else if (sm > 1.0) {
            sm = 1.0;
        }
        return sm;
    }

    public static double student_tDen(final double v, final double t) {
        return student_c(v) * Math.pow(1.0 + t * t / v, -0.5 * (v + 1.0));
    }

    public static double student_c(final double v) {
        return Math.exp(logGamma((v + 1.0) / 2.0))
                / (Math.sqrt(3.141592653589793 * v) * Math.exp(logGamma(v / 2.0)));
    }

    public static double logGamma(final double xx) {
        final double stp = 2.50662827465;
        final double[] cof = { 76.18009173, -86.50532033, 24.01409822, -1.231739516, 0.00120858003, -5.36382E-6 };
        double x = xx - 1.0;
        double tmp = x + 5.5;
        tmp = (x + 0.5) * Math.log(tmp) - tmp;
        double ser = 1.0;
        for (int j = 0; j < 6; ++j) {
            ++x;
            ser += cof[j] / x;
        }
        final double retVal = tmp + Math.log(2.50662827465 * ser);
        return retVal;
    }
}