Hi Istvan,
It's not a surprise that the python code is slower than the equivalent C++
code. Have a look at the file
src/wrapper/SWIG_files/linux_darwin/gp_wrap.cpp (the C++ file generated with
swig): you can see that creating a gp_Pnt from coordinates requires that the
_wrap_new_gp_Pnt function is called, then _wrap_gp_Pnt_SetCoord__SWIG_1.
That means that calling gp_Pnt(0,0,0) from python runs about 50 lines of C++
code. The wrapper code size/speed is independant from the C++ function
wrapped: you won't see any difference if you call OCE/OCC methods that
require high computation (boolean ops, STEP import/export etc.). It's not
the case when calling "atomic" methods (creating a gp_Pnt from coords for
instance).
In my opinion, if you look for performance in your python code, the best way
to proceed is to:
- identify loops that may create a bottleneck
- implement these loops in C++ functions
- wrap these functions with SWIG
- call the functions from python
This will solve performance (as well as memory) issues.
You can easily extend pythonocc with your own SWIG modules. You can for
instance copy/paste the src/wrapper/Visualization folder to
src/wrapper/MyFunctions. Modify the C++ and .i files, and add this new
python module to the setup.py script so that it is compiled with the usual
python setup.py build install.
Thomas
2011/10/8 István Csanády <istvancsan...@gmail.com>
> Hi,
>
> I made some tests with pythonOCC and with the pure C++ OCE. According
> to my measurements the 'same' code in python is about 10 times slower
> than the C++ code. For example the following python code:
>
> for i in xrange(10000):
> p = gp_Pnt(0,0,0)
> face =
> BRepBuilderAPI_MakeFace(gp_Sphere(gp_Ax3(p,gp_Dir(1.,0.,0.)),50.)).Face()
>
> compared to the C++ code:
>
> for (int i = 0; i<10000; ++i) {
> gp_Pnt p(0,0,0);
> gp_Sphere sphere(gp_Ax3(p,gp_Dir(1.,0.,0.)),50.);
> TopoDS_Face face = BRepBuilderAPI_MakeFace(sphere).Face();
> }
>
> The python version is about 8 times slower if I turn off the gc and
> about 10 times if I turn it on.
>
> Does anybody have any perfomance tips to make the pythonOCC code faster?
>
> István
>
> _______________________________________________
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