The for Cholesky and sparse LDLt there are methods for reusing an existing 
symbolic factorization. They are cholfact!/ldltfact!(Factorization,Matrix) 
so you can e.g. do

```

julia> A = sprandn(100,100,0.1) + 10I;


julia> F = cholfact(Symmetric(A));


julia> cholfact!(F, Symmetric(A - I));

```


See 
https://github.com/JuliaLang/julia/blob/f8d67f7521287d9325e91fd2142dad5f222e6eaf/base/sparse/cholmod.jl#L1260-L1272.




On Friday, July 8, 2016 at 4:40:45 AM UTC-4, Gabriel Goh wrote:
>
> Hey,
>
> I have a sequence of sparse matrix factorizations I need to do, each one a 
> different matrix but with the same sparsity structure. Is there a way I can 
> save the AMD (or any other) ordering that sparsesuite returns, it does not 
> need to be recomputed each time?
>
> Thanks a lot for the help!
>
> Gabe
>

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