'''[http://sourceforge.net/project/showfiles.php?group_id=18733%|%Bignum]''',
by [Colin McCormack], is a [critcl] wrapper to [https://gmplib.org/%|%libgmp].



** See Also **

   [bignum in pure Tcl], by [SS]:   

   [http://web.archive.org/web/20071115221157/http://www.unixreview.com/documents/s=10102/ur0610g/ur0610g.htm%|%Book Review:  BigNum Math] ,by [CL] ,2006:   

   [http://tip.tcl.tk/237%|%Arbitrary-Precision Integers for Tcl 8.5 TIP #237]:   

   [Big bitstring operations]:   

   [Big Floating-Point Numbers]:   

   [Big integer routines]:   

   [big integer to floating enhancement to Tcl]:   

   [BigFloat for Tcl]:   

   [Bignums Fast and Dirty]:   

   [math::bigfloat]:   

   [math::bignum]:   



** Requirements **

   libgmp3 >= 4.1.1:   or similar under Linux; get it from any GNU archive (if you haven't got it). To recompile it, you'll need the latest version of [critcl].


** Installation **

Unpack in /usr/lib, /usr/local/lib, or wherever your tcl resides



** Description **

Bignum provides the following packages:

   bigint:   which provides wrappers for arbitrary precision integers
   bigfloat:   which provides wrappers for arbitrary precision floats
   bignum:   both bigint and bigfloat

Of necessity, licensed under GPL, since libgmp is.


----

[stevel] 2005-01-27:

I've modified bignum to use the latest [Critcl],  and built a cross-platform
library Starkit with binaries for Linux, Windows and OSX
[http://tcl.tk/starkits/bignum.kit]

To use, either unpack the Starkit and copy the contents of the lib directory
into somewere on your auto_path, or just source it directly

======none
tclkit
% source bignum.kit
% package require bignum
% bigint::add 1111111111111111111111111111 2222222222222222222222222222
3333333333333333333333333333
======

The binaries on Windows and Linux are statically linked against libgmp (and therefore self-contained) but I couldn't get this working on OSX so you'll need to have gmp installed on your LDPATH to use bignum on OSX. I'll have another go later.

The modified source is available at [http://www.digitalsmarties.com/pub/bignum.tar.gz]

----

[LES] 2005-07-27: Using bignum.kit from [sdarchive] with [ActiveTcl] 8.5 on
Windows 98, I ran this command...

======
::bigint::powm 5 6 0
======

...and Tcl crashed (pure DOS or Tkcon). It only seems to happen with the 0, but
it does happen every time. Maybe I shouldn't be using 0, I admit I do not
understand what that function really does (I wanted to calculate a large number
raised to a large power). But I don't think that [Tcl] or [bignum] should crash
on me just because I threw a zero at it.  :-)

[Lars H]: '''powm''' is probably "power modulo" (a very common operation in
many cryptographical algorithms), so a zero as last argument is likely to lead
to "divide by zero" conditions.  This could either be a bug in libgmp, or a
failure of the wrapper to catch input not supported by that library, but come
Tcl 8.5 we'll most likely have equivalent functionality in the core anyway
(happy, happy; joy, joy).




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