How to evaluate the performance of K-means?

Hi,

I would like to evaluate the performance of k-means. I saw the below cost function (1) online, where wik=1 for data point xi if it belongs to cluster k; otherwise, wik=0. Also, μk is the centroid of xi’s cluster. But I don't know what 'm' is.

Does anyone understand what 'm' is in the below cost function?

Answer 1

[Adam Danz]

"...where wik=1 for data point xi..."

That would suggest that m is the number of data points since that summation is iterating over i.

Indeed, this is the correct interpretation (source).