MATLAB: Percent residual

Question

Hello,

I am trying to use the cftool and I got the residual plot fromt it, which is r=y-y^. Is there anyway to make it show a percent residual on the plot? (ie. how many percent the data is off from the fit curve)

Thanks!

Answer 1

You could save your fitting values to workspace, using cftool choose analysis and there select the option evaluate fit at Xi (in your case Xi is your x) . Now if you save those results you 'll have a structure containing xi and yfit. You can calculate percent residuals r(%)=100*(yi-yifit)./yi. Just be careful in case your original data aren't sorted by x value to sort them because the output results of fitting analysis are sorted to xi.