The types of problems I am trying to solve are as follows:

Given a set of co-ordinates such as: (1,2), (3,3), (6,2), (7,1), a value of k such as k=3 and an initial set of centroids such as c1=(2,2) and c2=(5,4), perform the k-means/median algorithm.

Now, with samples that small, I can easily work it out on paper. However, if I have 200 co-ordinates to start with and 10 centroids, it starts to get a lot more tricky.

I have already found this calculator: https://scistatcalc.blogspot.com/2014/01/k-means-clustering-calculator.html and several others which serve a similar function. I have also found python code doing similar operations. However, all these tools initialize centroids randomly or using k-means++. I, on the other hand, want to initialize the centroids manually.

Is there an online/offline tool/code/platform that can achieve this?