Re: [firedrake] PyOP2 code generation and C interface
Hi Eike, Two important questions there. I think the argument for using ctypes rather than swig is that ctypes is automatic and robust. Swig seems to involve more manual intervention and complexity. The code generation happens in two places. The user kernel is either already a C string or (more usually) is a Coffee AST. The Coffee AST has the built-in ability to generate the C code for that part. However I suspect you are more interested in where the code generation for the wrapper code happens. This happens in host.JITModule.compile . It uses a wrapper template from sequential.JITModule (sequential.JITModule is a subclass of host.JITModule). Is that what you were after? Cheers, David On 12 January 2015 at 22:46, Eike Mueller <e.mueller@bath.ac.uk> wrote:
Dear firedrakers,
am I right in saying that PyOP2 (and firedrake) uses ctypes to access the methods in the compiled C-libraries? Why did you use ctypes (and not swig, for example)? I.e. you generate c source files, compile them into .so libraries and then call that code through ctypes? Which files should I look at to understand how this works for a simple example (say a parloop)? compilation.py seems to load a .so library, but where is all the code generation?
Thanks,
Eike
--
Dr Eike Hermann Mueller Research Associate (PostDoc)
Department of Mathematical Sciences University of Bath Bath BA2 7AY, United Kingdom
+44 1225 38 5633 <+44%201225%2038%205633> e.mueller@bath.ac.uk <http://people.bath.ac.uk/em459/>http://people.bath.ac.uk/em459/
-- Dr David Ham Departments of Mathematics and Computing Imperial College London http://www.imperial.ac.uk/people/david.ham
Hi David, thanks, yes, that's what I was looking for, I will have a look at the code. I'm asking because our new PhD student, who will work on code generation for Molecular Dynamics, started this week. So I wanted to get some ideas as to what you are doing. Thanks, Eike -- Dr Eike Hermann Mueller Research Associate (PostDoc) Department of Mathematical Sciences University of Bath Bath BA2 7AY, United Kingdom +44 1225 38 5633 e.mueller@bath.ac.uk http://people.bath.ac.uk/em459/
On 13 Jan 2015, at 10:21, David Ham <David.Ham@imperial.ac.uk> wrote:
Hi Eike,
Two important questions there. I think the argument for using ctypes rather than swig is that ctypes is automatic and robust. Swig seems to involve more manual intervention and complexity.
The code generation happens in two places. The user kernel is either already a C string or (more usually) is a Coffee AST. The Coffee AST has the built-in ability to generate the C code for that part. However I suspect you are more interested in where the code generation for the wrapper code happens. This happens in host.JITModule.compile . It uses a wrapper template from sequential.JITModule (sequential.JITModule is a subclass of host.JITModule).
Is that what you were after?
Cheers,
David
On 12 January 2015 at 22:46, Eike Mueller <e.mueller@bath.ac.uk> wrote: Dear firedrakers,
am I right in saying that PyOP2 (and firedrake) uses ctypes to access the methods in the compiled C-libraries? Why did you use ctypes (and not swig, for example)? I.e. you generate c source files, compile them into .so libraries and then call that code through ctypes? Which files should I look at to understand how this works for a simple example (say a parloop)? compilation.py seems to load a .so library, but where is all the code generation?
Thanks,
Eike
--
Dr Eike Hermann Mueller Research Associate (PostDoc)
Department of Mathematical Sciences University of Bath Bath BA2 7AY, United Kingdom
+44 1225 38 5633 e.mueller@bath.ac.uk http://people.bath.ac.uk/em459/
-- Dr David Ham Departments of Mathematics and Computing Imperial College London
http://www.imperial.ac.uk/people/david.ham _______________________________________________ firedrake mailing list firedrake@imperial.ac.uk https://mailman.ic.ac.uk/mailman/listinfo/firedrake
On 13 Jan 2015, at 18:45, Eike Mueller <e.mueller@bath.ac.uk> wrote:
thanks, yes, that's what I was looking for, I will have a look at the code. I'm asking because our new PhD student, who will work on code generation for Molecular Dynamics, started this week. So I wanted to get some ideas as to what you are doing.
Note, fwiw, that we don't hold up the pyop2 code generation as a paragon of good programming practice. If you're looking for examples of excellent code gen, we can probably point to better ones. Lawrence
participants (3)
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David Ham
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Eike Mueller
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Lawrence Mitchell