On Apr 4, 2009, at 9:09 AM, Vic Kelson wrote: > Robert, > Thatnks for your helpful note. I can't seem to make it work with gcc > on OS X.
Hmm... that's the same platform I use. > I keep getting an error from gcc. I haven't had time to sort > through it yet. I think I'll build a little test problem (I tried > embedding your cod in my existing code and I might have created > another error). Maybe you could post a snippet of the error you're getting? > Just to be sure, when I use your code to make a cdouble, the real and > imaginary parts are the same size as a python float, right? Yes. Python floats are wrappers of double (and Python complexes wrap a pair of doubles). > Thanks! > --v > > > On 4/4/09, Robert Bradshaw <[email protected]> wrote: >> On Apr 3, 2009, at 10:21 PM, Vic Kelson wrote: >> >>> Greetings all, >>> >>> Sorry for the incomplete message, I'm re-sending it. >>> >>> I'm in need of fast computations on complex numbers from Cython. >>> I've been converting a Python groundwater flow model code to >>> Cython, but I'm reaching the point where I'd really prefer to have >>> native C complex math. Up to now, I've used some little C routines >>> that I can call with multiple floats (the C code converts to/from >>> complex for my purposes). However, I'm nearly to the point where >>> I'll need to store series coefficients for performance purposes, >>> and then I'll either need to hide them in float arrays (and that's >>> extremely nasty), or something like that. >>> >>> I'd like to say something like >>> >>> cdef class Foo: >>> cdef cfloat z >>> >>> def __cinit__(self, float x, float y): >>> self.z = cfloat(x, y) >>> >>> cdef cfloat func(Foo self, float x, float y): >>> return-some-gnarly-function of x, y, and self.z >>> >>> >>> Or something like that, where 'cfloat' maps to the appropriate type >>> in the C compiler, e.g. "double _Complex" in gcc. >>> >>> I've seen this discussed in the archives. Has it been implemented? >>> Is there some pre-release code that essentially works? I only need >>> the four math functions, conjugate, abs, and log. >> >> Yes, I've started this, as it comes up in my research too (number >> theory, computing values of L-functions). I hope to have something >> releasable soon. In the meantime, you can do >> >> cdef extern from "complex.h": >> ctypedef double cdouble "double complex" >> cdef double creal(cdouble) >> cdef double cimag(cdouble) >> cdef cdouble _Complex_I >> >> cdef inline cdouble new_cdouble(double x, double y): >> return x + _Complex_I*y >> >> Of course, the ctypedef is wrong, it will think it can go back to >> doubles (and Python objects) without any problem, but it works for >> now. >> >>> THANKS! I think Cython will revolutionize my research work! >> >> That's the goal :) Please cite us if it does. >> >> - Robert >> >> _______________________________________________ >> Cython-dev mailing list >> [email protected] >> http://codespeak.net/mailman/listinfo/cython-dev >> > > -- > Sent from my mobile device > > Vic Kelson > [email protected] > _______________________________________________ > Cython-dev mailing list > [email protected] > http://codespeak.net/mailman/listinfo/cython-dev _______________________________________________ Cython-dev mailing list [email protected] http://codespeak.net/mailman/listinfo/cython-dev
