Test Gamma of large number #56

phylonco-beast/src/test/java/phylonco/beast/evolution/readcountmodel/TestGamma.java

@@ -0,0 +1,51 @@
+package phylonco.beast.evolution.readcountmodel;
+
+import org.apache.commons.math3.special.Gamma;
+
+public class TestGamma {
+
+    public static void testOne() {
+        double x = 142;
+        double gamma = Gamma.gamma(x);
+        double logGamma = Gamma.logGamma(x);
+        double gamma2 = Math.exp(logGamma);
+
+        System.out.println("gamma(" + x + ") = " + gamma);
+        System.out.println("logGamma(" + x + ") = " + logGamma);
+        System.out.println("gamma2 = exp( logGamma(" + x + ") ) = " + gamma2);
+        double y = Gamma.gamma(141) * 141;
+        System.out.println("y = gamma(141) * 141 = " + y);
+
+        System.out.println("log( gamma(" + y + ") ) = " + Math.log(y));
+//        System.out.println("exp( logGamma(" + y + ") ) = " + Math.exp(Gamma.logGamma(y)));
+
+        // https://www.wolframalpha.com/input?i=gamma%28142%29
+        // Input: Γ(142)
+        // Result (decimal approximation): 1.8981437590761709694285264141107677937281750118953493737972... × 10^243
+
+    }
+
+    public static void testTwo() {
+
+        double x = 300;
+        double gamma = Gamma.gamma(x);
+        double logGamma = Gamma.logGamma(x);
+        double gamma2 = Math.exp(logGamma);
+
+        System.out.println("gamma(" + x + ") = " + gamma);
+        System.out.println("logGamma(" + x + ") = " + logGamma);
+        System.out.println("gamma2 = exp( logGamma(" + x + ") ) = " + gamma2);
+//        double y = Gamma.gamma(141) * 141;
+//        System.out.println("y = gamma(141) * 141 = " + y);
+//
+//        System.out.println("log( gamma(" + y + ") ) = " + Math.log(y));
+    }
+
+
+
+    public static void main(String[] args) {
+
+        testTwo();
+
+    }
+}