Using error in splinetool with more complicated functions

In splinetool, I understand that I can see the error in a spline by giving the original function in this way:

>> splinetool

-> Input your own data

1. Put vector of nodes in first box
2. Put function in 3rd box, e.g., cos or exp

Q: How can I use a more complicated function, e.g., x*cos(x)? I've tried @(x) x.*cos(x), x*cos(x), etc. in the 3rd box, but I keep getting errors.

If you just give vectors of data points (or call splinetool(x,y)), you get error = 0 b/c MATLAB doesn't know the original function. How can I tell it the function?

Answer 1

[John D'Errico]

Looks like the code is a bit buggy.

Save this function m-file on your search path.

function y = myfun(x)
y = x.*cos(x);

Then type the name myfun, into the field where it asks for a function name.

[Michelle Ghrist]

Yes - this worked! Thank you.