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How to use if, else conditional loop on anonymous function handle?

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hello_world
hello_world on 3 Aug 2018
Answered: Albert Fan on 3 Aug 2018
For the following example, given at https://www.mathworks.com/help/stats/evalclusters.html:
eva = evalclusters(meas, 'kmeans', 'CalinskiHarabasz', 'klist',[1:6])
Now, in the following example we use anonymous function handle:
load fisheriris
myfunc = @(X,K)(kmeans(X, K, 'emptyaction','singleton', 'replicate',5));
eva = evalclusters(meas, myfunc, 'CalinskiHarabasz', 'klist',[1:6])
kmeans returns indices, cluster center location, etc. I will like to put an if condition on myfunc before I pass it eva. So if other words, if the given condition fails, I will not like to run evalclusters.
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Accepted Answer

Albert Fan
Albert Fan on 3 Aug 2018
First of all, you cannot add a complex if statement in an anonymous function. The workaround is similar to what Adam has mentioned, is that you can create a regular function and pass the function handle in. for example:
eva = evalclusters(meas, @myfunc, 'CalinskiHarabasz', 'klist',[1:6])
function myfunc
% code
if condition
%do stuff
end
end
Additionally, the optimal cluster number is the result of evalclusters, which means you should not use that number as a condition of the clustering algorithm to stop execution. Otherwise, I personally do not know a way to stop evalcluster inside myfunc. However, if you just want to play with numbers, you can call exit() to stop the entire program. If you still want to execute something after evalclusters, then you could set a global variable and when you meet the condition, you set the variable to true and in mufunc, if that variable is true, do nothing and return. But that is rather complex and not a very good practice.

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