On Wed, Sep 8, 2010 at 5:35 PM, Michael Gilbert wrote: > On Wed, 8 Sep 2010 15:44:02 -0400, Michael Gilbert wrote: >> On Wed, Sep 8, 2010 at 12:23 PM, Charles R Harris wrote: >> > >> > >> > On Wed, Sep 8, 2010 at 9:46 AM, Michael Gilbert >> > <[email protected]> wrote: >> >> >> >> On Wed, 8 Sep 2010 09:43:56 -0600, Charles R Harris wrote: >> >> > On Wed, Sep 8, 2010 at 9:26 AM, Michael Gilbert >> >> > <[email protected] >> >> > > wrote: >> >> > >> >> > > Hi, >> >> > > >> >> > > Are there any plans to add support for decimal floating point >> >> > > arithmetic, as defined in the 2008 revision of the IEEE 754 standard >> >> > > [0], in numpy? >> >> > > >> >> > > >> >> > Not at the moment. There is currently no hardware or C support and >> >> > adding >> >> > new types to numpy isn't trivial. You can get some limited Decimal >> >> > functionality by using python classes and object arrays, for instance >> >> > the >> >> > Decimal class in the python decimal module, but the performance isn't >> >> > great. >> >> > >> >> > What is your particular interest in decimal support? >> >> >> >> Primarily avoiding catastrophic cancellation when subtracting >> >> large values. I was planning to use the decimal class, but was >> >> curious whether support for the IEEE standard was coming any time soon. >> >> >> > >> > If you just need more precision, mpmath has better performance than the >> > Decimal class. Also, it might be possible to avoid the loss of precision by >> > changing the computation, but I don't know the details of what you are >> > doing. >> >> Just wanted to say that numpy object arrays + decimal solved all of my >> problems, which were all caused by the disconnect between decimal and >> binary representation of floating point numbers. It would be really >> nice to have IEEE decimal floating point since python's decimal module >> is a bit slow, but I can see thats going to be a very long process. > > FYI, gcc 4.2 introduced initial support for decimal floats. However, > various macros like DEC32_MAX, and printf support for dd, df, and dl is > not yet implemented making it rather hard to work with.
A reference would probably be useful: http://gcc.gnu.org/onlinedocs/gcc-4.2.4/gcc/Decimal-Float.html As with all gcc documentation, its rather terse :/ Best wishes, Mike _______________________________________________ NumPy-Discussion mailing list [email protected] http://mail.scipy.org/mailman/listinfo/numpy-discussion
