How to vectorize a complex function?

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Mohammad Shojaei Arani
Mohammad Shojaei Arani on 23 Nov 2022
Answered: Paul on 23 Nov 2022
I have a rather complex function but I need to vectorize it in order to be able to use a matlab optimization package. My function is
g=@(par) nonbcon(par,J,N,X0,X,EZ,H,H_coeff,Coeff,knots,mesh_fine,M,SplineType,w);
You do not need to know the details of this function. g, accepts a row vector "par" and then as output gives either 0 or 1. However, I need to vectorize g so that it accepts a matrix A and performs the same operation on each row of A. I tried to use arrayfun but it is a bit complicated for me. I need something like the following (of course, this is wrong):
G=@(y)arrayfun(@(x) nonbcon(x),y(i,:));
but, I do not know how to modify G to do the job for me.
Any idea?
Thanks in advance!
Mohammad Shojaei Arani
Mohammad Shojaei Arani on 23 Nov 2022
OK. Thanks!
It seems that my only option is to use for-loop as this is not aparently paralaleisable

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Answers (1)

Paul on 23 Nov 2022
Hi Babak,
Here is a one line solution. Whether or not it's more efficient/effective/clearer than the loop is an open question.
Test data for input
test = rand(4,3);
ans = 4×1
1.9232 1.5945 0.8897 1.4173
Function that accepts a row vector and returns 0 or 1
g = @(par) double(sum(par,2)>1);
Loop solution
r1 = zeros(4,1);
for ii = 1:4,
r1(ii) = g(test(ii,:));
r1 = 4×1
1 1 0 1
One line solution
r2 = cellfun(g,mat2cell(test,ones(size(test,1),1)))
r2 = 4×1
1 1 0 1


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