MATLAB: Constraining a fitted curve

Question

Hi all,

I'm created cubic fitted curves in matlab based on a set of data points. There is however one requirement that I have to meet: the fitted curve can not decrease in y value as x increases. What I would like to happen is that whenever the fitted curve is supposed to decrease in y value, the curve is somehow constrained so that it flattens out (slope of 0). Is there any possible way to do this?

Answer 1

I'd strongly recommend that you look at a file exchange submission by John D'Errico titled "Shape Modeling Language"

http://www.mathworks.com/matlabcentral/fileexchange/24443