For what it's worth, I think it would be nice to translate and include
ARPACK to lisp and maxima.
Does it include routines to map out the structure of sparse matrices?
For instance, is there an analog of the "find" program in matlab.
This lists the indices of the non-zero elements of a matrix.
Thanks for your suggestion about A.v_old.
-sen
On Mon, 11 Dec 2006, Robert Dodier wrote:
> On 12/11/06, Raymond Toy <raymond.toy at ericsson.com> wrote:
>
>> How am I supposed to run this? Esparse(A,27,30,1e-10)?
>>
>> If so, I have no problems running it on my copy of cmucl (on solaris).
>> However, Esparse just says I should increase MAX or decrease ERR.
>
> Esparse works OK for me too, as others have reported.
>
> Esparse runs much faster if makelist(sum(A[i,j]*v_old[j],j,1,s),i,1,s)
> is replaced by A . v_old -- the . indicates noncommutative
> multiplication in Maxima.
>
> Dunno if we've discussed this before, but there is a Fortran
> package named ARPACK which computes a subset of the
> eigenvectors and eigenvalues. IIRC it is much faster than
> computing all eigenvectors & eigenvalues when just a few
> need to be computed. ARPACK is suitable for sparse matrices
> because only a matrix-vector product needs to be computed --
> no need to store the entire matrix. If there is in interest in such
> problems, ARPACK could be a candidate for translation to Lisp.
>
> FWIW
> Robert
> _______________________________________________
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> Maxima at math.utexas.edu
> http://www.math.utexas.edu/mailman/listinfo/maxima
>
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