On Thursday, August 8, 2013, Matthew Rocklin wrote:
>
> It should be simple to translate SymPy.Piecewise to a recursive
>>> Theano.switch (after translating SymPy.LT to theano.lt, etc.) I'll get
>>> on this soon. Does this sound reasonable to you Fred?
>>>
>>
>> It sound reasonable and is the first thing I suggest to try.
>>
>
> Working on this now.
>
> > SymPy C Codegen and Theano
>>>
>>> @Fred, how hard would it be to leverage SymPy's C codegen in Theano?
>>> This might be a lot cleaner than wrapping raw SymPy operations and might
>>> substantially extend Theano's support of scalar expressions. Do you have a
>>> performant Bessel function op? I'll bet SymPy could be made to do this
>>> quite well.
>>>
>>> @Aaron / @Ondrej, if you're reading this thread could you point us to
>>> the best place to start looking at C codegen in SymPy? Alternatively can
>>> you point to an active community member who would be able to do so?
>>>
>>>
>> @Matt, you already did a new Theano op with C code. I think it is the
>> only "easy" way to wrap other people c code in Theano. If the person
>> already know this C code AND a little of Python AND NumPy C-API, it isn't
>> very hard to a new Theano op with C code. Otherwise, doing the first such
>> op ask to learn a few think and could ask a few days. You already did this,
>> so you have a good idea of the work it need.
>>
>> Now the questions is how is done the SymPy code gen? Is just just string
>> template that is filled with dtype and other stuff? If we can just call one
>> SymPy function with the information of what we want and it return a string
>> with the C code it could be relatively easy. The only questions is about
>> how to handle the variable name to pass the information around. At worst,
>> we wrap the sympy c code in a c function, then make a small wrapper c code
>> that take the Theano c variable name and call this function. So not very
>> hard as Theano provide what is needed.
>>
>
> It looks like codegen is the relevant high-level api call
>
> In [1]: from sympy.utilities.codegen import
>
> In [2]: expr = sin(x)**2
>
> In [3]: [(c_name, c_code), (h_name, c_header)] = codegen(("f", expr), 'C',
> 'test', header=False)
>
> In [4]: print c_code
> #include "test.h"
> #include <math.h>
>
> double f(double x) {
>
> return pow(sin(x), 2);
>
> }
>
> The work I did rarely dealt with making and using functions. I'll go over
> past work and see what I can do. Expect some calls for help though!
>
If you figure out how to do something that's under-documented, please
document it. Our code generation needs a lot more documentation, especially
high-level narrative documentation.
Aaron Meurer
> --
> You received this message because you are subscribed to the Google Groups
> "sympy" group.
> To unsubscribe from this group and stop receiving emails from it, send an
> email to sympy+unsubscr...@googlegroups.com <javascript:_e({}, 'cvml',
> 'sympy%2bunsubscr...@googlegroups.com');>.
> To post to this group, send email to sympy@googlegroups.com<javascript:_e({},
> 'cvml', 'sympy@googlegroups.com');>
> .
> Visit this group at http://groups.google.com/group/sympy.
> For more options, visit https://groups.google.com/groups/opt_out.
>
>
>
--
You received this message because you are subscribed to the Google Groups
"sympy" group.
To unsubscribe from this group and stop receiving emails from it, send an email
to sympy+unsubscr...@googlegroups.com.
To post to this group, send email to sympy@googlegroups.com.
Visit this group at http://groups.google.com/group/sympy.
For more options, visit https://groups.google.com/groups/opt_out.
