I need to take the convolution with a function f and g, where g is a piecewise defined function.
Could anyone direct me how to define a piece-wise function handle in MATLAB?
i.e.

g(x) = { x ^2 : x>0 ; 0 : x<0}

Pretty elementary stuff I'd assume but it's something I've never done before.
Thanks.

https://www.mathworks.com/matlabcentral/newsreader/view_thread/278199?requestedDomain=www.mathworks.com

http://www.mathworks.com/matlabcentral/newsreader/view_thread/20924

perhaps one of those will help?

This post was edited by carteblanche on Apr 17 2016 08:35pm

I didn't understand the code in the first link about 0 and 1 logicals. Think you could explain what's going on here...and how I would use his example to code a piecewise function of the form:

g(x) = {A*exp(-x) if x>0 ; 0 if x<0}

Link 2 wasn't too helpful as I'm sure it doesn't need to be that complicated.

This post was edited by SoSSoS on Apr 17 2016 08:51pm

from context, looks like "false" evaluates to 0 and "true" evaluates to 1. a quick google search confirmed it (http://www.mathworks.com/help/matlab/ref/false.html).

we can take advantage of that to strategically define your function to include all cases in such a way the "false" values of 0 will remove the cases you don't want, whereas the "true" cases will keep the cases you do want. so you multiply your constraint with its corresponding expression and add them all together

we'll look at your first example:

if x>0 => x^2
if x<0 => 0

step 1: multiply the terms together:
(x>0) * (x^2)
(x<0) * (0)

Step 2: add them together:

(x>0)*x^2 + (x<0) * 0

looking at sample value, say x = -1:
(false)*x^2 + (true) * 0
=(0)*x^2 + (1) * 0
=(1) * 0
= 0

looking at x=1:
(true)*x^2 + (false) * 0
=(1)*x^2 + (0) * 0
=(1)*x^2
=x^2

which is what you wanted

This post was edited by carteblanche on Apr 17 2016 09:09pm

I didn't need up ending this but thank you