[Numpy-discussion] Numpy complex types, packing and C99
Pauli Virtanen
pav@iki...
Wed Jul 1 15:34:00 CDT 2009
On 2009-07-01, Charles R Harris <charlesr.harris@gmail.com> wrote:
[clip]
> OK. I don't see a problem then. As David says the ufuncs
> already work that way. <checks c99> Hmm... do we want to
> implement creal{l,,f} and cimag{l,,f} also?
They might come useful.
> They are built in functions in gcc, can we detect that?
Don't know, probably we can?
> Anyway, those functions would make rewriting the current
> complex functions pretty easy. Or do we want to rewrite the
> current functions to be ABI compatible with c99?
I think that for scipy.special this would be useful. Of course,
the operator semantics for complex numbers can't be used there,
but still sticking closer to C99 could be useful.
A separate question is whether we want to implement Numpy's
complex ufuncs using the C99 ones when they are available.
I had a branch for this:
http://github.com/pv/numpy-work/tree/c99-complex-umath
This has some risks: the system-provided complex-valued functions
may be broken in different ways, or suffer from some subtle
flaws. This is likely more common than having broken real-valued
functions that have been around quite a while longer. (To give an
example: casinh(1e-20) == 0 with GNU Libc 2.9.)
--
Pauli Virtanen
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