NM3(0, 3PI/2, 0.0001)

package labs;

public class Lab3 {
	private static double e;
	private static int n = 0;
	
	private static double function(double x) {
		return -Math.sin(x);
	}
	
	private static double gold(double l, double r){
		double  lc = r - (r-l)/1.618034,
				rc = l + (r-l)/1.618034;
		n++;
		
		double b1 = function(lc);
		double b2 = function(rc);
		double buf = function(lc) - function(rc);
		if (buf == 0){
			l = lc;
			r = rc;
		} else if (buf > 0) {
			l = lc;
		} else {
			r = rc;
		}
		
		if (r - l < e) {
		    return (r + l) /2;
		} else {
			return gold(l, r);
		}
	}
	
	private static double half(double l, double r){
		double center = (l + r)/2.0;
		n++;
		
		double buf = function(center-(e/2.0)) - function(center+(e/2.0)); 
		if (buf == 0 || r - l < 2*e){
			return center;
		} else if (buf > 0) {
			return half(center, r);
		} else {
			return half(l, center);
		}
	}
	
	public static void start(double left, double right, double epsilon){
		e = epsilon;
		System.out.println("Half:\t"+ half(left, right) +"\nin " + Integer.toString(n) + " steps");
		n = 0;
		System.out.println("Gold:\t"+ gold(left, right) +"\nin " + Integer.toString(n) + " steps");
	}
}