Can anyone help me?

Jun 25, 2006 2 Replies

Can anyone help me?



I am currently doing research on sparseness matrix issues. As I am carrying on this topic, I had a problem that don't know what to do. Basically the problem is as follows:


A and B are originally both sparse matrix, and I have to calcuate P=(inv(B)*A)^(-2), when the order of P is small say 32 by 32, I still can apply P into my algorithm and find a good solution, but when the order is large, say 72 by 72 , and I applied it in Matlab@, I got a warning like below


Warning: Matrix is close to singular or badly scaled. Results may be inaccurate. RCOND = 2.781682e-021.


If the order of A and B are larger, say 1000 by 1000, then my system is



just not responding at all no matter how long I wait and matlab is switch off automatically.


Can anyone help me to find a way slove the P matrix in large sparse case in Matlab, which can avoid the matrix becomes singular? Many thanks.


Khan.



Yes we can. Esp when the subject says nothing about the problem. And only about your needs. State your problem in the subject. Besides that a math group is proberbly better.

Bad programming on matlabs part then (good programs handle overload..).

Quick route to solution. Implement your functions inv() mult() etc.. in C. Run it on a decent unix machine. Alternative use bigiron for matlab =)

Why don't you try posting your question in sci.math.symbolic?

Join the Discussion

Have something to add? Share your thoughts — no account required.

Didn't find your answer?

Ask the community — no account required