I have have  a linear algebra library in Python, but the incentive for
using  a query language is that it's declarative and you get optimisation
for free.  The only hassle with  SQL is that it forces you to declare a
schema but even so it looks like the best option - XQuery requires too much
courage.


On Tue, Dec 31, 2013 at 2:27 PM, jean-marc Mercier <
[email protected]> wrote:

> As far as I understand, you want to write a linear algebra module using
> XQUERY ?
> If so, I opened a thread some months ago about this idea. My opinion today
> is that this is a false good idea at present time.
>
> 1) XQUERY would be really good for writing concise, efficient linear
> algebra modulus.
> 2) However, I strongly recommend to wait a little bit for starting coding
> : the current version of XQUERY (3.0) suffers from performance issues. A
> linear algebra modulus written in XQUERY is expected to have performances
> performances 1000 X slower than its corresponding C++ or JAVA (you can
> measure it precisely). Any mathematician linear algebra modulus would
> probably trashed your modulus after the first test.
>
> Hope this helps
>
>
>
> 2013/12/31 Ihe Onwuka <[email protected]>
>
>> Assuming a sparse representation it is about 4 lines of SQL. This is
>> known not least because you can read enough articles and papers that
>> discuss it and it optimises well. The obvious google search does not reveal
>> any corresponding XQuery discussion, neither does it appear to have
>> surfaced on this or the eXist mailing list (allowing for my deficient
>> search skills). For something so "trivial" I thought that was rather
>> strange. Hence I thought it would be prudent to ask  before naively
>> embarking on a  600k X 40k matrix multiplication.
>>
>>
>>
>> On Tue, Dec 31, 2013 at 11:31 AM, Andrew Welch 
>> <[email protected]>wrote:
>>
>>>
>>> It should be pretty trivial...
>>>
>>> On 31 Dec 2013 11:07, "Ihe Onwuka" <[email protected]> wrote:
>>> >
>>> > Has anybody tried this in XQuery or if I am so foolish (not yet but
>>> give me time) would I be the courageous  <culturalReference>
>>> http://www.youtube.com/watch?v=ik8JT2S-kBE</culturalReference> early
>>> adopter.
>>> >
>>> >
>>> > _______________________________________________
>>> > [email protected]
>>> > http://x-query.com/mailman/listinfo/talk
>>>
>>>
>>
>> _______________________________________________
>> [email protected]
>> http://x-query.com/mailman/listinfo/talk
>>
>
>
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