MonetDB: SciQL-2 - handle non-rectangular array tiles

Ying Zhang Y.Zhang at cwi.nl
Thu Aug 15 14:25:31 CEST 2013


Hai Stefan,

>> - disable the check on (max - min + 1 = size), since it only holds for
>> stepsize = 1.
>>  maybe we should just remove this check, since we don't have step size in
>>  the
>>  tiling aggr impl. functions, do we?
> 
> IMHO, our current tiled aggregation implementation inherently assumes (and thus requires) that all dimensions of the given array have step-size == 1. Since ARRAYtiles*() does not get the step sizes of the given array as parameters, the check (max - min + 1 = size) was/is IMHO the only way to check/ensure that we are indeed working on an array where all dimensions have step-size == 1.

Ok. I don't recall this assumption, so I was testing the code with a small array with step-size > 1, which triggers the assertion.  After having disabled this check, the query actually returns correct results.  Time to check this assumption, maybe it's easy to get rid of it.

>> teleios_noa_bsm.sql:
>> now we can get rid of the workarounds
>> 
>> more tests needed...
> 
> Indeed --- I'll resume me test tonight or tomorrow …

I tested the with a tiny array to see that e.g., computing SUM of a diagonal line works correctly.
I rerun the BSM queries, with the real implementation of clump_4connected_1.  The queries finished without errors, but when checking the found fires, I only got a black picture...
I'll do more test this afternoon.

Jennie

> 
> Best,
> Stefan
> 
> -- 
> | Stefan.Manegold at CWI.nl | DB Architectures   (DA) |
> | www.CWI.nl/~manegold/  | Science Park 123 (L321) |
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