[SciPy-user] umfpack installation (and dsolve error)

Eric Friedman ejf27@cornell....
Mon Mar 23 12:38:27 CDT 2009


Nils Wagner <nwagner <at> iam.uni-stuttgart.de> writes:


> > btw, the reason for this is that I'm having a problem 
> >with dsolve which I think
> > is a bug, but may just be my error.
> > 
> > for example:
> > 
> > a=matrix([[1,1],[1,1]])
> > b= matrix([.5,.5]).T
> > dsolve(a,b)
> > yields [.5,.5]
> > which is not a solution of ax=b  - I think...
> > (I also entered the matrix as sparse)
> > 
> > any ideas what's going on here?
> > 
> > thanks,
> > Eric
> > 


> Hi Eric,
... 
> Please not that your (dense) matrix is singular.
> 

sorry, I should have mentioned that I need to be able to solve singular matrices
and will settle for any solution (since there will be many of them).
(For nonsparse I've been using linalg.lstsq, which works fine for this.)

any suggestions on which sparse solver to use?

thanks
Eric



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