[SciPy-user] linsolve.factorized was: Re: Using umfpack to calculate a incomplete LU factorisation (ILU)

Robert Cimrman cimrman3@ntc.zcu...
Thu Mar 8 11:10:30 CST 2007


Robert Cimrman wrote:
> Nils Wagner wrote:
>> Just out of interest
>>
>> Is there something comparable with
>>
>> sigma_solve = linsolve.splu(A - sigma*B).solve
>>
>> available in UMFPACK ?
> 
> Sure, although it is not a oneliner. This is the relevant part of the
> docstring:

> Would you be interested in exposing this in linsolve, as, say,
> 
> def factorized( A ):
>     if isUmfpack and useUmfpack:
> 	# This must be written...
>     else:
>         return splu( A ).solve


Well, I did it since I am going to need this, too :-)

In [3]:scipy.linsolve.factorized?
...
Definition:     scipy.linsolve.factorized(A)
Docstring:
    Return a fuction for solving a linear system, with A pre-factorized.

    Example:
      solve = factorized( A ) # Makes LU decomposition.
      x1 = solve( rhs1 ) # Uses the LU factors.
      x2 = solve( rhs2 ) # Uses again the LU factors.

This uses UMFPACK if available.

cheers,
r.


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