Fwd: Re: Supporting sparse matrices

[boisvert@nist.gov]

Sender: Anders Peterson <anders_peterson@optimatika.se>
Subject: Re: Supporting sparse matrices


Colt supports sparse matrices

http://dsd.lbl.gov/%
7Ehoschek/colt/api/cern/colt/matrix/impl/SparseDoubleMatrix2D.html

and ojAlgo has abstractions that would allow anyone to add support for 
all kinds of matrices.

http://ojalgo.org/generated/org/ojalgo/matrix/store/MatrixStore.html

/Anders

kazar001@umn.edu wrote:
> please goto SPARSKIT documentation/code in UMN.EDU domain. you can 
> convert many of these fortran codes to java in a day/week/month 
> depending on your speed of coding. thanks
>
> On Feb 20 2007, Daniel Winterstein wrote:
>
>> Firstly, let me say thank you for making Jama available. The 
>> interface is clear and gives me exactly the functionality I wanted. 
>> I've found it very useful. And forgive me if this topic has already 
>> been discussed to death.
>>
>> Re. having JAMA as part of Java ("the primary linear algebra package 
>> for Java" as the website proposes), I think it would be good to add 
>> in a layer of abstraction, in order to support the use of sparse 
>> matrices.
>>
>> Jama itself is tied to working with dense matrices, represented by 
>> arrays. This is inappropriate for sparse matrices. Sparse matrices 
>> occur naturally in a lot of important problems. Specialised 
>> representations and codes can give _orders of magnitude_ speed ups 
>> for sparse problems. Anyone who is unfamiliar with the subject, I 
>> recommend http://citeseer.ist.psu.edu/duff98matrix.html for an 
>> excellent intro to computing with sparse matrices.
>>
>> I would like a linear algebra system which allowed different matrix 
>> representations and codes. High-level code should be able to work 
>> with any of these without worrying abut what is going on 'under the 
>> hood'.
>>
>> This shouldn't take a great deal of modification. Perhaps as simple 
>> as extracting an IMatrix interface  from Matrix, then implementing a 
>> simple sparse-matrix to test that this makes sense. It can then be 
>> left for others to implement efficient codes for different types of 
>> sparse matrix.
>>
>> Your thoughts?
>> - Daniel
>>
>> -----------------------------------------------------------
>> "I know nothing, understand less, & most of that is wrong."
>>
>>   Daniel Winterstein
>>   http://thinktankmaths.co.uk
>>  
>>
>>
>>
>>
>>
>
>
>



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