From: Roy Stogner <roystgnr@ic...>  20121120 22:41:38

On Tue, 20 Nov 2012, Jens Lohne Eftang wrote: > http://sourceforge.net/mailarchive/message.php?msg_id=24029850 > > in the devel list there were plans on changing the API for > cholesky_solve and lu_solve such that the interface with two arguments > did not change the arguments, and another interface with only one > argument would. > > There seems to be only one implementation if cholesky_solve and lu_solve > in the current libmesh version, which takes two arguments. Does it > change the rhs input vector? (It seems to me that it doesn't but I just > wanted to make sure). I changed the cholesky_solve implementation recently (r6285, just a few weeks ago) so that it shouldn't modify the rhs. John Peterson seems to have changed the lu_solve implementation in a similar way, three years ago shortly after that thread. Nobody seems to have wanted to bother to add singleargument versions of the methods. > Also it seems that cholesky_solve() will change my matrix (due to the > factorization I assume). Yes; the factorization is still inplace. > Is it correct that subsequent solves will give the correct answer, > but that if I need the matrix for matrix multiplication I will have > to keep a copy? This should be correct.  Roy 