好的,这段代码是另一个问题,但我无法弄清楚如何添加我更新的代码。我得到了这个代码工作并提出了正确的答案,但它并没有停止根据我的while循环条件。我不确定那里我做错了什么?答案明显收敛,所有值都是正确的,只是在忽略循环时。
/* Newton Raphson Method*/
import java.util.Scanner;
import static java.lang.Math.*;
public class NewtRaphEx {
// Creating Function f = x - cos(3.5x)
double f = 0.0;
double df = 0.0;
public static double function(double x) {
return (x - cos(3.5 * x));
}
public static double dfunction (double x) {
return (1 + 3.5*sin(3.5 * x));
}
public static void main (String[] args) {
//Initialising all variables
double xn = 0.06;
double xnew = 0.0;
double e_allow = 0.001;
double fn = 0.0;
double eps = 0.0;
double dfn = 0.0;
double dx = 0.0;
int n = 0;
int nMax = 10000;
do {
for (n = 0; n <= nMax; n++) {
fn = function(xn);
dfn = dfunction(xn);
dx = -(fn / dfn);
xnew = xn + dx;
xn = xnew;
eps = abs(dx / xn);
n = n + 1;
}
} while (eps <= e_allow || n < nMax);
System.out.print("N" + "\t" + "X" + "\t" + "F(x)" + "\t" + "dF(x)" + "\t");
System.out.println("delX" + "\t" + "X_new" + "\t" + "Epsilon");
System.out.format("%d\t" + "%.3f\t" + "%.3f\t" + "%.3f\t" + "%.3f\t" + "%.3f\t" + "%.3f", n, xn, fn, dfn, dx, xnew, eps);
}
}
答案 0 :(得分:2)
表达式
eps <= e_allow || n < nMax
到达时评估为true,因此for
循环将再次运行,设置n = 0
,从而设置无限循环。
具体来说,你会:
eps = 0.0;
e_allow = 0.001;
n = 10002; // due to the increment inside the loop
nmax = 10000;
就这样:
eps <= e_allow || n < nMax
0.0 <= 0.001 (true) OR 10002 <= 10000 (false) -> true