add numerical integration example

yuemingl · yuemingl · May 18, 2015 · Mar 20, 2015 · Mar 20, 2015 · Mar 21, 2015
commit 311168df5d0a85ce17c3ef44277d383d3ad334b0
diff --git a/src/symjava/examples/NumericalIntegration.java b/src/symjava/examples/NumericalIntegration.java
@@ -0,0 +1,29 @@
+package symjava.examples;
+
+import static symjava.math.SymMath.PI;
+import static symjava.math.SymMath.exp;
+import static symjava.math.SymMath.pow;
+import static symjava.math.SymMath.sqrt;
+import static symjava.symbolic.Symbol.x;
+import symjava.bytecode.BytecodeFunc;
+import symjava.domains.Domain;
+import symjava.domains.Interval;
+import symjava.symbolic.Expr;
+import symjava.symbolic.Integrate;
+import symjava.symbolic.utils.JIT;
+
+public class NumericalIntegration {
+
+	public static void main(String[] args) {
+		//Define the interal
+		Domain I = Interval.apply(-10, 0).setStep(0.01);
+		//Define the integral: cumulative distribution function
+		Expr cdf = Integrate.apply(exp(-0.5*pow(x,2))/sqrt(2*PI), I);
+		System.out.println(cdf); //\int_{-10.0}^{10.0}{1/\sqrt{2*\pi}*e^{-0.5*x^2}}dx
+
+		//Compile cdf to perform numerical integration
+		BytecodeFunc f = JIT.compile(cdf);
+		System.out.println(f.apply()); //1.0
+	}
+
+}