Rational numbers

**Larry Bates** · Feb 23 '07, 04:05 PM

Re: Rational numbers

Martin Manns wrote:

Hi,
>
I am starting to use rationals and since I found no batteries included,
I tried out the mxNumber package.
>
However, I get strange warnings on comparison operations
(which however seem to yield correct results):
>
---
$ python
Python 2.4.3 (#1, Jan 15 2007, 15:46:19)
[GCC 4.1.1 (Gentoo 4.1.1-r3)] on linux2
Type "help", "copyright" , "credits" or "license" for more information.

>>>from mx.Number import *
>>>a=Rational(0 ,1)
>>>a

0/1

>>>str(a)

'0.0'

>>>b=-500000000000000 000000000000000 000000000000000 0000000000000
>>>b

-500000000000000 000000000000000 000000000000000 0000000000000L

>>>a==b

__main__:1: RuntimeWarning: tp_compare didn't return -1, 0 or 1
False
---
>
How do I get rid of these warnings?
>
Is there any rational number library around that
1) is comparably fast for large denominators
2) allows deriving types from Rationals without wrapping?
>
Regards
>
Martin
>
P.S. The respective mailing list does not like me, so that I try my
luck here.

I quick search of Google turned up:

Python Cookbook

http://books.google.com/books?id=1Shx_VXS6ioC&pg=PA625&lpg=PA625&dq=python+rational+number+library&source=web&ots=BA8_4EXdQ4&sig=aDEnYA99ssKe7PSweVNyi8cS2eg

Portable, powerful, and a breeze to use, Python is the popular open source object-oriented programming language used for both standalone programs and scripting applications. It is now being used by an increasing number of major organizations, including NASA and Google.Updated for Python 2.4, The Python Cookbook, 2nd Edition offers a wealth of useful code for all Python programmers, not just advanced practitioners. Like its predecessor, the new edition provides solutions to problems that Python programmers face everyday.It now includes over 200 recipes that range from simple tasks, such as working with dictionaries and list comprehensions, to complex tasks, such as monitoring a network and building a templating system. This revised version also includes new chapters on topics such as time, money, and metaprogramming.Here's a list of additional topics covered:Manipulating textSearching and sortingWorking with files and the filesystemObject-oriented programmingDealing with threads and processesSystem administrationInteracting with databasesCreating user interfacesNetwork and web programmingProcessing XMLDistributed programmingDebugging and testingAnother advantage of The Python Cookbook, 2nd Edition is its trio of authors--three well-known Python programming experts, who are highly visible on email lists and in newsgroups, and speak often at Python conferences.With scores of practical examples and pertinent background information, The Python Cookbook, 2nd Edition is the one source you need if you're looking to build efficient, flexible, scalable, and well-integrated systems.

Class Library For Numbers Module

http://calcrpnpy.sourceforge.net/clnum.html

Welcome to General Multiprecision PYthon

http://gmpy.sourceforge.net/

-Larry

**Martin Manns** · Feb 23 '07, 04:55 PM

Re: Rational numbers

On Fri, 23 Feb 2007 09:52:06 -0600
Larry Bates <lbates@websafe .comwrote:

I quick search of Google turned up:
>

Python Cookbook

http://books.google.com/books?id=1Shx_VXS6ioC&pg=PA625&lpg=PA625&dq=python+rational+number+library&source=web&ots=BA8_4EXdQ4&sig=aDEnYA99ssKe7PSweVNyi8cS2eg

Portable, powerful, and a breeze to use, Python is the popular open source object-oriented programming language used for both standalone programs and scripting applications. It is now being used by an increasing number of major organizations, including NASA and Google.Updated for Python 2.4, The Python Cookbook, 2nd Edition offers a wealth of useful code for all Python programmers, not just advanced practitioners. Like its predecessor, the new edition provides solutions to problems that Python programmers face everyday.It now includes over 200 recipes that range from simple tasks, such as working with dictionaries and list comprehensions, to complex tasks, such as monitoring a network and building a templating system. This revised version also includes new chapters on topics such as time, money, and metaprogramming.Here's a list of additional topics covered:Manipulating textSearching and sortingWorking with files and the filesystemObject-oriented programmingDealing with threads and processesSystem administrationInteracting with databasesCreating user interfacesNetwork and web programmingProcessing XMLDistributed programmingDebugging and testingAnother advantage of The Python Cookbook, 2nd Edition is its trio of authors--three well-known Python programming experts, who are highly visible on email lists and in newsgroups, and speak often at Python conferences.With scores of practical examples and pertinent background information, The Python Cookbook, 2nd Edition is the one source you need if you're looking to build efficient, flexible, scalable, and well-integrated systems.

Class Library For Numbers Module

http://calcrpnpy.sourceforge.net/clnum.html

http://gmpy.sourceforge.net/

Sorry that I did not point these out initially.

+ clnum seems to be slower and for speed may be compiled to wrap gmp so
that it is just an additional layer between python and gmp .

+ gmpy is looking pretty unmaintained (dead) to me (newest update of
cvs 10 months ago).

+ boost indeed is a quite nice C++ library. However, I fear that I
would end up writing the python wrappers for operators (+ - * / min
max cmp etc.) myself. I would like to avoid this since these operators
should work correctly for any type (not just int and float) and I have
little experience with verifying such generic code. The problems
encountered in the mxNumber wrapper support this notion.

Martin

**Martin Manns** · Feb 23 '07, 05:55 PM

Re: Rational numbers / alternatives to mxNumber

On Fri, 23 Feb 2007 11:39:11 -0500
Martin Manns <mmanns@gmx.dew rote:

+ boost indeed is a quite nice C++ library. However, I fear that I
would end up writing the python wrappers for operators (+ - * / min
max cmp etc.) myself. I would like to avoid this since these operators
should work correctly for any type (not just int and float) and I have
little experience with verifying such generic code. The problems
encountered in the mxNumber wrapper support this notion.

I just saw the pyboost-linux-0.1.1 package and tried it out.

ImportError: /home/mn/notes/libboost_python .so.1.34.0: undefined
symbol: PyUnicodeUCS4_F romEncodedObjec t

It seems to have problems with UCS2 compiled python.
Any robust rational wrapper out there?

**bearophileHUGS@lycos.com** · Feb 23 '07, 06:45 PM

Re: Rational numbers

Martin Manns:

+ gmpy is looking pretty unmaintained (dead) to me (newest update of
cvs 10 months ago).

I have used it on Py2.5, so it seems to work anyway, and it's fast
enough for my purposes. And probably soon some alex-shaped life will
show up elsewhere.

Bye,
bearophile

**Marc 'BlackJack' Rintsch** · Feb 23 '07, 06:45 PM

Re: Rational numbers

In <20070223113911 .05dcc555@local host>, Martin Manns wrote:

+ gmpy is looking pretty unmaintained (dead) to me (newest update of
cvs 10 months ago).

What CSV activities do you expect? This package seems to be pretty
stable. As long as there is no bug or incompatible changes in the
underlying library I would not expect changes to that package.

Ciao,
Marc 'BlackJack' Rintsch

**mensanator@aol.com** · Feb 23 '07, 06:45 PM

Re: Rational numbers

On Feb 23, 10:39 am, Martin Manns <mma...@gmx.dew rote:

On Fri, 23 Feb 2007 09:52:06 -0600
>
Larry Bates <lba...@websafe .comwrote:

I quick search of Google turned up:

>

http://books.google.com/books?id=1Sh...lpg=PA625&dq=p...

Class Library For Numbers Module

http://calcrpnpy.sourceforge.net/clnum.html

http://gmpy.sourceforge.net/

>
Sorry that I did not point these out initially.
>
+ clnum seems to be slower and for speed may be compiled to wrap gmp so
that it is just an additional layer between python and gmp .
>
+ gmpy is looking pretty unmaintained (dead) to me (newest update of
cvs 10 months ago).

Actually, gmpy is being maitained even if SourceForge isn't up to
date.

I got my gmpy 1.04a for Python 2.5 Windows binary from

<http://home.comcast.ne t/~casevh>

I haven't used the rationals all that much, but been very
happy with them when I have.

>
+ boost indeed is a quite nice C++ library. However, I fear that I
would end up writing the python wrappers for operators (+ - * / min
max cmp etc.) myself. I would like to avoid this since these operators
should work correctly for any type (not just int and float) and I have
little experience with verifying such generic code. The problems
encountered in the mxNumber wrapper support this notion.
>
Martin

**casevh@comcast.net** · Feb 23 '07, 08:15 PM

Re: Rational numbers

On Feb 23, 10:34 am, "mensana...@aol .com" <mensana...@aol .comwrote:

On Feb 23, 10:39 am, Martin Manns <mma...@gmx.dew rote:
>

On Fri, 23 Feb 2007 09:52:06 -0600

>

Larry Bates <lba...@websafe .comwrote:

I quick search of Google turned up:

>

>http://books.google.com/books?id=1Sh...lpg=PA625&dq=p...
>http://calcrpnpy.sourceforge.net/clnum.html
>http://gmpy.sourceforge.net/

>

Sorry that I did not point these out initially.

>

+ clnum seems to be slower and for speed may be compiled to wrap gmp so
that it is just an additional layer between python and gmp .

>

+ gmpy is looking pretty unmaintained (dead) to me (newest update of
cvs 10 months ago).

I worked with Alex Martelli (gmpy's maintainer) to fix a bug found by
mensanator. With Alex's permission, I released it as gmpy 1.04a. Alex
has not updated cvs with the fix.

gmpy 1.04a compiles cleanly with the latest releases of Python and
GMP, so I consider it stable.

>
Actually, gmpy is being maitained even if SourceForge isn't up to
date.
>
I got my gmpy 1.04a for Python 2.5 Windows binary from
>
<http://home.comcast.ne t/~casevh>
>
I haven't used the rationals all that much, but been very
happy with them when I have.
>

casevh

**Martin Manns** · Feb 23 '07, 08:35 PM

Re: Rational numbers

On 23 Feb 2007 12:00:10 -0800
casevh@comcast. net wrote:

>
I worked with Alex Martelli (gmpy's maintainer) to fix a bug found by
mensanator. With Alex's permission, I released it as gmpy 1.04a. Alex
has not updated cvs with the fix.
>
gmpy 1.04a compiles cleanly with the latest releases of Python and
GMP, so I consider it stable.
>

Actually, gmpy is being maitained even if SourceForge isn't up to
date.

I got my gmpy 1.04a for Python 2.5 Windows binary from

<http://home.comcast.ne t/~casevh>

I haven't used the rationals all that much, but been very
happy with them when I have.

>
casevh
>

Thank you for all the replies.

I think that I am going to switch to gmpy.

Martin

**mensanator@aol.com** · Feb 23 '07, 10:25 PM

Re: Rational numbers

On Feb 23, 2:00 pm, cas...@comcast. net wrote:

On Feb 23, 10:34 am, "mensana...@aol .com" <mensana...@aol .comwrote:
>
>
>
>
>

On Feb 23, 10:39 am, Martin Manns <mma...@gmx.dew rote:

>

On Fri, 23 Feb 2007 09:52:06 -0600

>

Larry Bates <lba...@websafe .comwrote:
I quick search of Google turned up:

>

http://books.google.com/books?id=1Sh...lpg=PA625&dq=p...

Class Library For Numbers Module

http://calcrpnpy.sourceforge.net/clnum.html

http://gmpy.sourceforge.net/

>

Sorry that I did not point these out initially.

>

+ clnum seems to be slower and for speed may be compiled to wrap gmp so
that it is just an additional layer between python and gmp .

>

+ gmpy is looking pretty unmaintained (dead) to me (newest update of
cvs 10 months ago).

>
I worked with Alex Martelli (gmpy's maintainer) to fix a bug found by
mensanator. With Alex's permission, I released it as gmpy 1.04a. Alex
has not updated cvs with the fix.
>
gmpy 1.04a compiles cleanly with the latest releases of Python and
GMP, so I consider it stable.

Am I hallucinating? Didn't I see at least some version
of gmpy for Python 2.5 on SourceForge awhile back?
I distinctly remember thinking that I don't have to
direct people to your site, but SourceForge is not
showing anything beyond vesion 1.01 for Python 2.4.

>

Actually, gmpy is being maitained even if SourceForge isn't up to
date.

>

I got my gmpy 1.04a for Python 2.5 Windows binary from

>

<http://home.comcast.ne t/~casevh>

>

I haven't used the rationals all that much, but been very
happy with them when I have.

>
casevh

**casevh@comcast.net** · Feb 23 '07, 11:05 PM

Re: Rational numbers

Am I hallucinating? Didn't I see at least some version
of gmpy for Python 2.5 on SourceForge awhile back?
I distinctly remember thinking that I don't have to
direct people to your site, but SourceForge is not
showing anything beyond vesion 1.01 for Python 2.4.

Alex released versions 1.02 and 1.03 as CVS updates only. I think he
may have made an announcement that 1.02 included alpha support for
Python 2.5. 1.04a is 1.03 with one additional fix. I don't think there
has been an official release, though.

casevh

**Gabriel Genellina** · Feb 23 '07, 11:35 PM

Re: Rational numbers

En Fri, 23 Feb 2007 12:35:19 -0300, Martin Manns <mmanns@gmx.dee scribió:

I am starting to use rationals and since I found no batteries included,
I tried out the mxNumber package.
>
However, I get strange warnings on comparison operations
(which however seem to yield correct results):

mx.Number.Ratio nal is horribly broken. They break this rule:

a==b =hash(a)==hash( b)

so they can'b be used as dictionary keys, by example.
Try the other packages suggested. I've used clnum without problems.

--
Gabriel Genellina

**aleaxit@gmail.com** · Feb 23 '07, 11:35 PM

Re: Rational numbers

On Feb 23, 12:00 pm, cas...@comcast. net wrote:
...

+ gmpy is looking pretty unmaintained (dead) to me (newest update of
cvs 10 months ago).

>
I worked withAlex Martelli(gmpy's maintainer) to fix a bug found by
mensanator. With Alex's permission, I released it as gmpy 1.04a. Alex
has not updated cvs with the fix.

Heh, I see why one might get that impression -- I'm in the process of
moving gmpy from sourceforge (where I find it harder and harder, and
ever more problematic, to work) to code.google.com 's new hosting
facility -- gmpy 1.02 prerelease (more updated than that "1.04a", and
particularly including your fix, Case) is already available at
http://code.google.com/p/gmpy/ but I have made no official
announcement yet (partly because what's available is yet limited:
sources, and binaries for Python 2.3, 2.4 and 2.5 but only for MacOSX
10.4 on Macs with intel processors)... building binaries for Windows
(not having a Windows machine or development system) or Universal
binaries for the Mac (due to problems building Universal versions of
the underlying GMP in its latest, 4.2 incarnation... I'm running out
of PPC-based Macs, and have none left with MaxOSX 10.3...) is much
more problematic for me.

To call this (Google Code) release 1.02, with a "1.04" (?) out from
another source, may be confusing, but I'd rather not "force" the
number upwards

I do have one new co-owner on the Google Code "version" of gmpy (Chip
Turner, once author of a similar GMP wrapper for perl, now a Python
convert and a colleague of mine) but I suspect that won't make the
building of Windows (and Universal Mac) binaries much easier. If
anybody who has easy access to Microsoft's MSVC++.NET (and is willing
to try building GMP 4.2 with/for it), or a PPC Mac with XCode
installed (possibly with MacOSX 10.3...), wants to volunteer to build
"the missing binaries" for the platforms that the current owners of
gmpy can't easily support, we could complete, test and release the
definitive 1.02, and move on with the development (I could get
enthusiastic about this again, if I could develop just the sources,
and the binaries for the one architecture I really use -- Macs w/intel
-- rather than strive each time with binaries for architectures that
are quite a pain for me...!-).

Anybody who's interested in helping out is welcome to mail me and/or
use the "wiki" and "issues" entry of the Google Code gmpy site...

Thanks,

Alex

**aleaxit@gmail.com** · Feb 23 '07, 11:45 PM

Re: Rational numbers

On Feb 23, 2:52 pm, cas...@comcast. net wrote:

Am I hallucinating? Didn't I see at least some version
of gmpy for Python 2.5 on SourceForge awhile back?
I distinctly remember thinking that I don't have to
direct people to your site, but SourceForge is not
showing anything beyond vesion 1.01 for Python 2.4.

>
Alex released versions 1.02 and 1.03 as CVS updates only. I think he
may have made an announcement that 1.02 included alpha support for
Python 2.5. 1.04a is 1.03 with one additional fix. I don't think there
has been an official release, though.

Right: apparently sourceforce doesn't want me to do "releases" any
more (quite apart from the utter mess that doing a "release" on
sourceforce always was and still is), though I can still update the
cvs repository -- that's part of why I'm moving to Google Code
hosting.

Alex

**casevh@comcast.net** · Feb 23 '07, 11:55 PM

Re: Rational numbers

On Feb 23, 3:27 pm, alea...@gmail.c om wrote:

On Feb 23, 12:00 pm, cas...@comcast. net wrote:
...
>

+ gmpy is looking pretty unmaintained (dead) to me (newest update of
cvs 10 months ago).

>

I worked withAlex Martelli(gmpy's maintainer) to fix a bug found by
mensanator. With Alex's permission, I released it as gmpy 1.04a. Alex
has not updated cvs with the fix.

>
Heh, I see why one might get that impression -- I'm in the process of
moving gmpy from sourceforge (where I find it harder and harder, and
ever more problematic, to work) to code.google.com 's new hosting
facility -- gmpy 1.02 prerelease (more updated than that "1.04a", and
particularly including your fix, Case) is already available athttp://code.google.com/p/gmpy/but I have made no official
announcement yet (partly because what's available is yet limited:
sources, and binaries for Python 2.3, 2.4 and 2.5 but only for MacOSX
10.4 on Macs with intel processors)... building binaries for Windows
(not having a Windows machine or development system) or Universal
binaries for the Mac (due to problems building Universal versions of
the underlying GMP in its latest, 4.2 incarnation... I'm running out
of PPC-based Macs, and have none left with MaxOSX 10.3...) is much
more problematic for me.
>
To call this (Google Code) release 1.02, with a "1.04" (?) out from
another source, may be confusing, but I'd rather not "force" the
number upwards
>
I do have one new co-owner on the Google Code "version" of gmpy (Chip
Turner, once author of a similar GMP wrapper for perl, now a Python
convert and a colleague of mine) but I suspect that won't make the
building of Windows (and Universal Mac) binaries much easier. If
anybody who has easy access to Microsoft's MSVC++.NET (and is willing
to try building GMP 4.2 with/for it), or a PPC Mac with XCode
installed (possibly with MacOSX 10.3...), wants to volunteer to build
"the missing binaries" for the platforms that the current owners of
gmpy can't easily support, we could complete, test and release the
definitive 1.02, and move on with the development (I could get
enthusiastic about this again, if I could develop just the sources,
and the binaries for the one architecture I really use -- Macs w/intel
-- rather than strive each time with binaries for architectures that
are quite a pain for me...!-).
>
Anybody who's interested in helping out is welcome to mail me and/or
use the "wiki" and "issues" entry of the Google Code gmpy site...
>
Thanks,
>
Alex

I can keep building gmpy for Windows. I actually use MINGW since
getting GMP compiled under MSVC is "challangin g". I should be able to
build new binaries for Windows this weekend. And I would be happy to
point everyone to a real release.

casevh

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