#### 6.29 analytic linear system solving (27.11.97)

Forwarded from Olivier Froment SNCF - Ecole Centrale de Paris

I would like to solve symbolically a linear system of the (classical ) form : `Ax=b`

where A is "almost "full `6*6`

square matrix

Up to 5, that seems possible but with 6 the objects manipulated seem too large...

Is there something I can do for simplifying , before solving the system, the shape of matrix A
to make it work?

I once had a verb|16x16| matrix to deal with, and I found using the LU factorization to be
very helpful.

By coincidence I also recently wanted a symbolic solution for an "almost" full `6*6`

square
matrix. Mine solved, but took a long time to produce a very large and awkward
solution. In the end I found the LU decomposition much more useful (command
`linalg[LUdecomp](...)`

).

In fact it was fairly easy to apply an LU decomposition such as Croutâ€™s algorithm
(Numerical Recipes in C, W.H. Press et al. (1992)) manually to the matrix.