I am a biologist with some maths background... but not enough knowledge to solve this problem, so I would be really grateful if someone could help (and explain it at a level that a biologist might understand).
I have a large symmetrical matrix (1250 x 1250) which is made up of pairwise correlations between 1250 variables, such that row A = 1, A1B2, A1B3, ... A1B1250 and so on for all 1250 rows.
I would like to calculate modules of related variables, with no prior expectation about how many modules the 1250 variables will fall into.
I have some vague instructions that I should use the absolute correlation values to calculate edge weights, then use edge weights to determine clustering. The problem is that these instructions are too vague for me to make sense of. Specifically, I would like to know:
- How are edge weights calculated for this kind of symmetrical matrix?
- How are edge weights used to cluster variables?
I'd be very grateful for any help offered, either specific formula and explanation, or simply pointing me in the direction of another useful resource.
Thanks very much in advance,