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Re: [xsl] Increasing sequence ?

Subject: Re: [xsl] Increasing sequence ?
From: "Dimitre Novatchev dnovatchev@xxxxxxxxx" <xsl-list-service@xxxxxxxxxxxxxxxxxxxxxx>
Date: Sat, 28 Mar 2015 17:07:38 -0000

On Sat, Mar 28, 2015 at 3:17 AM, Michael Kay mike@xxxxxxxxxxxx
<xsl-list-service@xxxxxxxxxxxxxxxxxxxxxx> wrote:
>> With another sequence:
>>   (1, 0, 2 to 100000)
>> increasing2() takes 77ms, while the recursive increasing() takes only
>> 4.45ms -- or that means the recursive function is about 17 times
>> faster.
>> Maybe the BaseX developers didn't implement proper short-cutting for
>> the "every" expression.
> Or maybe they expand 2 to 100000 into an actual list of 99999 numbers prematurely.

I think BaseX is open source and we will find the answer in the code.

Even before that, here is another guess:

Maybe they are implementing the "every" expression using parallelism,
so they cannot stop the other three threads immediately when the
current thread finds that the condition is violated.

Just one example where parallel execution is outperformed by
sequential execution. The exact data may make parallel execution on it
significantly slower than simple sequential execution.

Speaking about BaseX:  Congratulations for their just announced 8.1
version. Among other things they implemented "efficient Finger Tree
algorithm for arrays" -- this is enormous -- really made my day.

Dimitre Novatchev
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