fwhm

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 A sinple function for determining the full width at half maximum
 Input: 
 x: the array of x-values
 f: the array of function values
 Output:
 fwhm: FWHM of f in the scale given by x
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0001 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
0002 % A sinple function for determining the full width at half maximum
0003 % Input:
0004 % x: the array of x-values
0005 % f: the array of function values
0006 % Output:
0007 % fwhm: FWHM of f in the scale given by x
0008 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
0009 function FWHM = fwhm(x,f)
0010 if nargin < 2
0011     f = x;
0012     x=[1:length(f)];
0013 end
0014 f1 = f-0.5*max(f);
0015 ind = find(f1(1:end-1).*f1(2:end) <=0);
0016 FWHM = x(ind(2))-x(ind(1));