Charles R Harris wrote: > > > On Jan 8, 2008 8:55 PM, David Cournapeau <[EMAIL PROTECTED] > <mailto:[EMAIL PROTECTED]>> wrote: > > Charles R Harris wrote: > > > > > > On Jan 8, 2008 8:42 PM, David Cournapeau > <[EMAIL PROTECTED] <mailto:[EMAIL PROTECTED]> > > <mailto:[EMAIL PROTECTED] > <mailto:[EMAIL PROTECTED]>>> wrote: > > > > Charles R Harris wrote: > > > > > > > > > On Jan 8, 2008 6:49 PM, Eric Firing < [EMAIL PROTECTED] > <mailto:[EMAIL PROTECTED]> > > <mailto:[EMAIL PROTECTED] <mailto:[EMAIL PROTECTED]>> > > > <mailto: [EMAIL PROTECTED] <mailto:[EMAIL PROTECTED]> > <mailto:[EMAIL PROTECTED] <mailto:[EMAIL PROTECTED]>>>> wrote: > > > > > > Bill Baxter wrote: > > > > On Jan 9, 2008 9:18 AM, Charles R Harris > > > <[EMAIL PROTECTED] > <mailto:[EMAIL PROTECTED]> > > <mailto:[EMAIL PROTECTED] > <mailto:[EMAIL PROTECTED]>> > > <mailto: [EMAIL PROTECTED] > <mailto:[EMAIL PROTECTED]> > > <mailto:[EMAIL PROTECTED] > <mailto:[EMAIL PROTECTED]>>>> wrote: > > > >> On Jan 8, 2008 5:01 PM, Bill Baxter < > [EMAIL PROTECTED] <mailto:[EMAIL PROTECTED]> > > <mailto:[EMAIL PROTECTED] <mailto:[EMAIL PROTECTED]>> > > > <mailto: [EMAIL PROTECTED] <mailto:[EMAIL PROTECTED]> > <mailto:[EMAIL PROTECTED] <mailto:[EMAIL PROTECTED]>>>> wrote: > > > >>> On Jan 9, 2008 8:03 AM, Charles R Harris > > > < [EMAIL PROTECTED] > <mailto:[EMAIL PROTECTED]> > > <mailto:[EMAIL PROTECTED] > <mailto:[EMAIL PROTECTED]>> > > <mailto:[EMAIL PROTECTED] > <mailto:[EMAIL PROTECTED]> > <mailto:[EMAIL PROTECTED] > <mailto:[EMAIL PROTECTED]>>>> > > > >> wrote: > > > >>>> On Jan 8, 2008 1:58 PM, Bill Baxter < > [EMAIL PROTECTED] <mailto:[EMAIL PROTECTED]> > > <mailto:[EMAIL PROTECTED] <mailto:[EMAIL PROTECTED]>> > > > <mailto: [EMAIL PROTECTED] <mailto:[EMAIL PROTECTED]> > <mailto:[EMAIL PROTECTED] <mailto:[EMAIL PROTECTED]>>>> wrote: > > > >>>>> If you're really going to try to do it, Charles, > > there's an > > > >>>>> implementation of float16 in the OpenEXR toolkit. > > > >>>>> http://www.openexr.com/ > > > >>>>> > > > >>>>> Or more precisely it's in the files in the Half/ > directory > > > of this: > > > >>>>> > > > >> > > > > > > http://download.savannah.nongnu.org/releases/openexr/ilmbase-1.0.1.tar.gz > > > >>>>> I don't know if it's IEEE conformant or not > (especially > > > w.r.t. NaN's > > > >>>>> and such) but it should be a good start. The code > > seems to > > > be well > > > >>>>> documented. > > > >>>> The license looks good, essentially BSD. The code is > > all C++, > > > which is > > > >> the > > > >>>> obvious way to go for this sort of thing, and I > would > > like to > > > stick with > > > >> it, > > > >>>> but that could lead to build/compatibility > problems. I > > think > > > NumPy > > > >> itself > > > >>>> should really be in C++. Maybe scons can help > with the > > build. > > > >>> Yeh, I was just thinking you'd rip out and C-ify > the main > > > algorithms > > > >>> rather than trying to wrap it as-is. > > > >> I'd rather not C-ify the thing, I'd rather C++-ify > parts of > > > NumPy. I note > > > >> that MatPlotLab uses C++, so some of the problems > must have > > > been solved. > > > > > > A big chunk of C++ in matplotlib has just been > replaced, largely > > > because > > > it was so hard to understand and extend for everyone > but its > > author. > > > There is still C++ code as well as C code in mpl. > Personally, I > > > prefer > > > the C. > > > > > > > > > > > If you think that's easier then go for it. > > > > > > The opinion that C++ would improve numpy is not > universal, > > and has > > > been > > > discussed. > > > > > > > http://article.gmane.org/gmane.comp.python.numeric.general/13244 > <http://article.gmane.org/gmane.comp.python.numeric.general/13244> > > > < > > > http://article.gmane.org/gmane.comp.python.numeric.general/13244> > > > > > > > > > Ah, the trick to interfacing C to C++ is to derive the C++ > classes > > > from the numpy structures and keep the function pointers. Then > > all the > > > offsets would work. I would think the main advantage of > C++ would be > > > in arithmetic operator overloading and using template > classes while > > > carefully restricting such things to numbers. Mostly, I would > > use C++ > > > inline class methods as shorthand that would compile to > what the C > > > approach would do. I suppose we could write a python > > preprocessor that > > > would do essentially the same thing; C++ started that way. > > Are you suggesting to write a compiler to be able to use > operator > > overloading ? :) More seriously, the problem of C/C++ is not > only at > > source level but also at binary level. > > > > > > As I tried to say, there are ways of dealing with the > compatibility > > problems at the binary level. > Sorry, I was not precise enough: I talked at the binary level wrt > compilers. C++ object code compiled by different compilers are not > always compatible, without talking about known linking problems. I am > > > This can also be true of C code unless you use compilers in the same > family. There are also issues, but they are much simpler. > The C++ name mangling can be worked around. name mangling is just the top of the iceberg. There are problems wrt to static initialization, exception, etc...; ABI compatibility is much easier to break in C++ than in C. And then, there is the problem of C++ ability of compilers.
http://developer.mozilla.org/en/docs/C%2B%2B_Portability_Guide http://techbase.kde.org/index.php?title=Policies/Binary_Compatibility_Issues_With_C%2B%2B I am not saying it is not possible, or that we should not do it: just that it has a high cost. IMHO, the benefits would have to be high. > I'm just thinking out loud about these things. Note that numpy already > uses what are essentially templates to generate C code using a Python > preprocessor, although perhaps the design could be a bit cleaner and > maybe a bit more general so as not to be limited to the C builtin types. I agree on this point (custom code generators use). Note that there are standard tools to generate simple templates in C (autogen). If what you want to do is to be able to use simple templates (by simple, I mean template function parametrized with the numerical type), C++ is overkill IMHO. cheers, David _______________________________________________ Numpy-discussion mailing list Numpy-discussion@scipy.org http://projects.scipy.org/mailman/listinfo/numpy-discussion
