fptest.java

来自「纯java操作系统jnode,安装简单和操作简单的个人使用的Java操作系统」· Java 代码 · 共 112 行

/*
 * $Id: FPTest.java,v 1.1 2003/11/25 11:41:41 epr Exp $
 */
package org.jnode.test;

import java.io.PrintStream;

/**
 * Test of floating point operations
 * 
 * @author epr
 */
public class FPTest {

	public static void main(String[] args) {
		
		final PrintStream out = System.out;

		testFloat(out);	
		testDouble(out);
		testTan(out);	
	}
	
	private static void testTan(PrintStream out) {
		out.println("testTan");
		
		for (double i = -5; i < 5; i += 0.5) {
			
			final double jvmResult = Math.tan(i);
			final double cpResult = StrictMathTest.tan(i);
			
			if (jvmResult != cpResult) {
				out.println("tan(" + i + ")=" + jvmResult + "\t" + cpResult);
			}
		}
		final double angle = Math.PI / 4.0;
		final double a = 1.0 - Math.cos(angle);
		final double b = Math.tan(angle);
		final double c = Math.sqrt(1.0 + b * b) - 1 + a;
		final float cv = (float)(4.0 / 3.0 * a * b / c);
		out.println("JVM: " + Math.tan(angle) + ", CP: " + StrictMathTest.tan(angle));
		out.println("CV: " + cv);		
	}
	
	
	private static void testFloat(PrintStream out) {
		out.println("testFloat");
		final float a = 45.5f;
		final float b = -7.11f;
		final double da = a;
		final double db = b;
		final int ia = (int)a;
		final int ib = (int)b;
		
		out.println("a      " + a);
		out.println("b      " + b);
		out.println("-a     " + (-a));
		out.println("-b     " + (-b));
		out.println("a + b  " + (a + b));
		out.println("a - b  " + (a - b));
		out.println("a * b  " + (a * b));
		out.println("a / b  " + (a / b));		
		out.println("sin(a) " + Math.sin(a));
		out.println("asin(a) " + Math.asin(a));
		out.println("cos(a) " + Math.cos(a));
		out.println("acos(a) " + Math.acos(a));
		out.println("tan(a) " + Math.tan(a));
		out.println("atan(a) " + Math.atan(a));
		out.println("sqrt(a) " + Math.sqrt(a));
		
		out.println("da    " + da);
		out.println("db    " + db);
		out.println("ia    " + ia);
		out.println("ib    " + ib);
		
		out.println();
	}

	private static void testDouble(PrintStream out) {
		out.println("testDouble");
		final double a = 45.5;
		final double b = -7.11;
		final float fa = (float)a;
		final float fb = (float)b;
		final int ia = (int)a;
		final int ib = (int)b;
		
		out.println("a      " + a);
		out.println("b      " + b);
		out.println("-a     " + (-a));
		out.println("-b     " + (-b));
		out.println("a + b  " + (a + b));
		out.println("a - b  " + (a - b));
		out.println("a * b  " + (a * b));
		out.println("a / b  " + (a / b));
		out.println("sin(a) " + Math.sin(a));
		out.println("asin(a) " + Math.asin(a));
		out.println("cos(a) " + Math.cos(a));
		out.println("acos(a) " + Math.acos(a));
		out.println("tan(a) " + Math.tan(a));
		out.println("atan(a) " + Math.atan(a));
		out.println("sqrt(a) " + Math.sqrt(a));
		
		out.println("fa    " + fa);
		out.println("fb    " + fb);
		out.println("ia    " + ia);
		out.println("ib    " + ib);
		
		out.println();
	}
}