寻找近似函数的绝对误差-MATLAB [英] finding absolute error of approximated function - matlab

问题描述

在实验过程中，我记录了几点.此后，我用9阶多项式对其进行了近似.我需要找到测量的绝对误差以及y轴上的近似函数.有什么主意吗?

During an experiment i registered several points. Thereafter I approximated them with 9th order polynomial. I need to find the absolute error of the measurements and the approximated function on y axis. Any idea?

*

y = [0.006332 0.04056 0.11813 0.1776723 0.23840 0.29827 0.358396...   
0.418149 0.4786 0.478154 0.538114 0.53862 0.598954 0.659804...
0.720267 0.781026 0.8412 0.901548 0.962022 1.022567 1.083291...
1.143653 1.20449 1.14398 1.02273 0.962285 0.90203 0.841474...
0.780881 0.720346 0.659896 0.579599 0.539505 0.478662 0.418963...
0.35859 0.299039 0.238886 0.179108 0.118999 0.058841 0.006249...
0.06189];
x2 = linspace (1,43,43);
x2 = x2';
y = y';
f = fit(x2,y,'poly9');
figure()
plot(f,x2,y)

推荐答案

这可以做到:

y_fit = f(x2);
error = y - y_fit;

hold on
plot(x2, error)

% Several popular error norms:
norm(error, 1)
norm(error, 2)
norm(error, Inf)

像y一样，变量error是向量.如果要将这个向量简化为一个数，可以使用一个范数. 有关错误规范的更多信息，请参见此.

Like y, the variable error is a vector. If you want to reduce this vector to a single number, you can use one the norms. See this for more on error norms.

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