Chris Lasher wrote: > Hello Pythonistas! > I'm looking for a way to duplicate entries in a symmetrical matrix > that's composed of genetic distances. For example, suppose I have a > matrix like the following: > > A B C > A 0.000000 0.500000 1.000000 > B 0.500000 0.000000 0.500000 > C 1.000000 0.500000 0.000000 > > Say I want to duplicate entry B; the resulting matrix would look like: > > A B B C > A 0.000000 0.500000 0.500000 1.000000 > B 0.500000 0.000000 0.000000 0.500000 > B 0.500000 0.000000 0.000000 0.500000 > C 1.000000 0.500000 0.500000 0.000000 > > The cases I'd like to do this for are more complicated, naturally, > where I want to duplicate different entries different numbers of times. > I'm aware of Numeric, Numarray, and NumPy, though I've not used any of > them, but I am not sure if any of them possess a simple means to > duplicate entries in a matrix. I started writing code on my own but I > can see it is becoming exponentially more complex, and before I proceed > any further, I want to make sure I'm not reinventing any wheels. If > anyone here has any advice on how to manipulate matrices in this > manner, I'd _greatly_ appreciate it! > > Thanks in advance, > Chris
Chris Very rusty at this sort of thing, but if you premultiply the first matrix by: 1 0 0 0 1 0 0 1 0 0 0 1 and postmultiply the result by: 1 0 0 0 0 1 1 0 0 0 0 1 I think you get what you want. (If that helps). Gerard -- http://mail.python.org/mailman/listinfo/python-list
