I use scikit-learn to get IRIS and WINE clusters for evaluating an algorithm for K-means clustering. The K-means algorithm is a heuristic algorithm for solving the "minimum-sum-of-squares-clustering (MSSC)" problem, that is, it does not guarantee to get an optimal solution for the MSSC. Therefore, I was wondering where I can find the optimal solutions of the IRIS and WINE instances of MSSC? Are you aware of any data sets for which the optimal clusters are available?
If such optimal solutions are not available, then I am wondering how different algorithms of K means are currently being compared?