[GRASS-user] v.generalize: does it take forever?

[Fábio Dias]

Attached is pdf generated with google-perf of v.generalize, using
g7b4. I'm running it again for trunk.
-=--=-=-
Fábio Augusto Salve Dias
http://sites.google.com/site/fabiodias/


On Sun, Jan 4, 2015 at 5:54 PM, Markus Metz
<markus.metz.giswork at gmail.com> wrote:
> On Wed, Dec 31, 2014 at 5:20 PM, Fábio Dias <fabio.dias at gmail.com> wrote:
>>
>> I fussed about the v.generalize code, thinking about pthread
>> parallelization. The geometry part of the code is *really* fast and
>> can be easily parallelized so it can run even faster. But, according
>> to the profile google-perf gave me, the real bottleneck is inside the
>> check_topo function (which uses static vars and inserts a new line
>> into the vector, not only checks if it breaks topo - got stuck a while
>> in there due to the misnomer). More specifically in the Rtree function
>> used to check if one line intersects other lines.
>>
>
> The function used in check_topo is Vect_line_intersection() which does
> much more than just testing for intersections. The process could be
> made much faster if Vect_line_check_intersection() would be modified
> such that connections by end points are ignored. But I don't know if
> this would break other modules or other functionality.
>
> Markus M
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