[GRASS-dev] gmath and gpde update

[Soeren Gebbert]

Dear developers,
thanks a lot for clarification.

In case we will use the meschach library within grass to replace the
existing LAPACK wrapper, my BLAS and solver implementation
and several numerical recipes algorithm (lu, eigenvalues solvers ...), i
will take the patched debian sources and integrate them into
grass.

IMHO the following changes have to be made in the meschach library:

* replacing malloc, calloc and realloc with the GRASS implementation
* replacing printf and fprintf with the GRASS implementation
* changing the error handling to use G_fatal_error and similar GRASS
functions
* adding the prefix G_math_ to all extern library functions (with
preprocessor directives)
* document the changes i made

Optionally:

* try to add OpenmMP derectives to matrix-vector and matrix-matrix
computation functions
* try to paralleling the LLT and LDLT solver
* write benchmarks and more tests

Changes in GRASS:

* replacing most of the gmath and current gpde stuff in GRASS with the
meschach implementation, but keeping the G_alloc_matrix and G_alloc_vector
functions
* integrate meschach in the doxygen documentation system

I think i will need one year again to implement this in my rare spare time.
;)

Do we need a vote to replace the gmath and gpde parts with meschach?
Any objections against it or criticism or suggestions?

Btw.: this is an interesting article describing the computation speed of
meschach in relation to other numerical libraries:
http://www.ibm.com/developerworks/opensource/library/l-matrix.html

Best regards
Soren



2009/1/11 Moritz Lennert <mlennert at club.worldonline.be>

> On 11/01/09 14:02, Glynn Clements wrote:
>
>> Moritz Lennert wrote:
>>
>>  Meschach is implemented in C and is able to replace the gmath library
>>>> completely with much better implementations.
>>>> I have integrated meschach into grass for testing purposes and, after
>>>> some very basic testing, it works nicely.
>>>> But im unsure if the licence of meschach is compatible with the GPL? Can
>>>> somebody please verify this? Im not an expert in licensing.
>>>>
>>> This seems to be the relevant part:
>>>
>>
>>  "The source code is available to be perused, used and passed on without
>>> cost, while ensuring that the quality of the software is not
>>> compromised."
>>>
>>> There is no mention of modification, and the second half of the sentence
>>> ("while ensuring that the quality of the software is not compromised")
>>> sounds quite suspicious to me. So, without claiming any expert knowledge
>>> either, I would be sceptical.
>>>
>>
>> Where did you find that?
>>
>
> http://www.netlib.org/c/meschach/readme
>
>  It appears to contradict:
>>
>>
>> http://packages.debian.org/changelogs/pool/main/m/meschach/current/copyright
>>
>
> It definitely does. I would tend to trust Debian more than the above...
>
> Moritz
>
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