防止Matlab舍入输出? [英] Prevent Matlab from rounding output?

问题描述

我正在运行一个简单的脚本来估计函数的根.一切正常，算法的每次迭代都会打印出当前的x和f(x)，但是当脚本完成并将x的最终估计值设置为函数的输出时，将返回该值并将其四舍五入到小数点后三位.

Im running a simple script to estimate roots for a function. Everything works great, each iteration of the algorithm prints off the current x and f(x), but when the script finishes and sets the final estimate of x as the output of the function the value is returned and rounded to 3 decimal places...

while k < maxit
    k = k + 1;
    dx = b - a;
    xm = a + 0.5*dx;       %  Minimize roundoff in computing the midpoint

    fm = feval(fun, xm, diameter, roughness, reynolds);

    fprintf('%4d  %12.20e  %12.4e\n',k,xm,fm); 

    if (abs(fm)/fref < feps) | (abs(dx)/xref < xeps) % True when root is found
        r = xm;  
    return;
end

这是输出的尾巴:

k       xm            fm
45  6.77444446476613980000e-003   1.3891e-012
46  6.77444446478035060000e-003  -1.3380e-011
47  6.77444446477324520000e-003  -5.9952e-012
48  6.77444446476969250000e-003  -2.3022e-012
49  6.77444446476791610000e-003  -4.5830e-013

    ans =

        0.0068

我不知道为什么要对输出进行四舍五入....我该如何防止呢?

i dont know why its rounding the output.... how do i prevent that?

推荐答案

在运行脚本之前尝试在命令行中键入'format longE'

try typing 'format longE' in the command line before running the script

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