I need to find local minima's in a graph(2-dimensional ) without curve fitting ; I have the F(x) and x values only

I have simulated data it gives the output and i need to find the position at which local minimum's occur also where maxima's occour too , to calculate the height of each peak

Answer 1

[Shashank Prasanna]

http://www.mathworks.com/help/matlab/ref/fminsearch.html

Answer 2

[Alan Weiss]

x = randn(10,2); % random 2-D x locations
y = 5*randn(10,1)+20; % random heights at the x locations
[maxy,r] = max(y); [miny,s] = min(y); % places where the extrema occur
maxpt = x(r,:)
minpt = x(s,:)

If you want to interpolate your data and optimize it that way, and you have Global Optimization Toolbox, see the example Pattern Search Climbs Mount Washington.

Alan Weiss

MATLAB mathematical toolbox documentation