Frequently asked questions, Computational Algebra

Q: What is meant by growth factor in Assignment 1.2?

A: The quotient between the largest element in factors L and U and the largest element in the original matrix A. A large growth factor means that you get a large rounding error.

Q: What is meant by error in the solution in Ass 1.2?

A: If you know the exact solution  it is
||e||=||xcomputed-xexact||
Otherwize you use the residual
||r||=||Axcomputed-b||
Try with an arbitrary vector b! Often the error is growing faster than the residual, when the matrix gets ill conditioned.

Q: How do I make my files availble to my collaborator?

A: Try the fs command! I think you should write
>fs setacl catalogue-name other-user rlidw
Replace italic text by the appropriate. The last is a set of options
r read
l list
i insert
d delete
w write