Re: gsl_linalg_solve_symm_cyc_tridiag problem

[Brian Gough <bjg at network-theory dot co dot uk>]

David Necas (Yeti) writes:
 > And, to be at least a little constructive: I've implemented
 > nonsymmetric tridiagonal system solvers (mainly because I don't
 > understand gsl_linalg_solve_symm_cyc_tridiag() and thus can't fix
 > it ;-) -- the non-cyclic is almost identical to
 > gsl_linalg_solve_symm_tridiag(), only doesn't require symmetrical
 > matrix, the cyclic solver uses Sherman-Morrison formula to
 > compensate for the offending corner elements after solving the
 > system w/o them.  A patch is attached, if you'd like to include it.
 > Note these routines have problems with too small N too, but it's
 > easy to fix them once one decides what to do in case of too small
 > N.
 >

Thanks -- I've added those in now.  Some tridiag test cases would be
useful if you have the chance to work on it.

Brian