Big Int support
-
Not exactly a Cocoa-related question, but it could be incorporated into
a Cocoa program. Is there a library or way to create 'big int' support
so a number isn't limited to the particular bounds of int, float, or
even an unsigned long?
Occasionally I need to do large number calculations (such as 2^1000
which is equal to
107150860718626732094842504906000181056140481170553360744375038837035105
112493612249319837881569585812759467291755314682518714528569231404359845
775746985748039345677748242309854210746050623711418779541821530464749835
819412673987675591655439460770629145711964776865421676604298316526243868
37205668069376 according to Mathematica), and it would be nice if I
could figure out how to do this myself so I wouldn't have to rely on
Mathematica (which is not cheap software if you aren't in Academia).
Chad Armstrong
<edenwaith...>
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On Monday, Jun 2, 2003, at 13:28 US/Eastern, Chad Armstrong wrote:
> Not exactly a Cocoa-related question, but it could be incorporated
> into a Cocoa program. Is there a library or way to create 'big int'
> support so a number isn't limited to the particular bounds of int,
> float, or even an unsigned long?
Check out NSDecimalNumber.
--
http://homepage.mac.com/clarkcox3/
<clarkcox3...>
Clark S. Cox, III
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I may have misunderstood your question, but here's a stab at it anyway.
If you're just talking about doing simple calculations on big numbers,
you can use the UNIX command "bc". It's a handle little
sort-of-desktop-calculator, and it's got a "man" page. For instance,
you can use "bc" to calculate 2-to-the-one-thousandth. (Or 2^10000, or
10^10000, or any similar large number.)
[monty:~] jeff% bc
bc 1.05
Copyright 1991, 1992, 1993, 1994, 1997, 1998 Free Software Foundation,
Inc.
This is free software with ABSOLUTELY NO WARRANTY.
For details type `warranty'.
2^1000
10715086071862673209484250490600018105614048117055336074437503883703\
51051124936122493198378815695858127594672917553146825187145285692314\
04359845775746985748039345677748242309854210746050623711418779541821\
53046474983581941267398767559165543946077062914571196477686542167660\
429831652624386837205668069376
(To get out of "bc", type control-D.)
On Monday, June 2, 2003, at 12:28 PM, Chad Armstrong wrote:
> Not exactly a Cocoa-related question, but it could be incorporated
> into a Cocoa program. Is there a library or way to create 'big int'
> support so a number isn't limited to the particular bounds of int,
> float, or even an unsigned long?
--
<jharrell...>
http://homepage.mac.com/jharrell
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From: Wayne Hasley <whasley...>
Date: Mon Jun 2, 2003 3:40:57 PM US/Eastern
To: Chad Armstrong <edenwaith...>
Subject: Re: Big Int support
On Monday, June 2, 2003, at 01:28 PM, Chad Armstrong wrote:
> Not exactly a Cocoa-related question, but it could be incorporated
> into a Cocoa program. Is there a library or way to create 'big int'
> support so a number isn't limited to the particular bounds of int,
> float, or even an unsigned long?
Finally a question I can answer!
You want an arbitrary-precision math library.
A long time ago I ported similar code to the Macintosh
These are usually done using BCD (Binary Coded Decimal).
I did a Google search. IBM provides source for their decNumber package;
an arbitrary-precision implementation of the specifications in ANSI C.
Warning! There are some heavy license requirements in this package. You
might want to search for another.
See http://www.alphaworks.ibm.com/tech/decNumber
Wayne
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would this really work, though? Here's from the documentation on
NSDecimalNumber:
> NSDecimalNumber, an immutable subclass of NSNumber, provides an
> object-oriented wrapper for doing base-10 arithmetic. An instance can
> represent any number that can be expressed as mantissa x 10^exponent
> where mantissa is a decimal integer up to 38 digits long, and exponent
> is an integer from -128 through 127.
hence, there wouldn't really be enough precision to detail all of
Chad's number:
> (such as 2^1000 which is equal to
> 10715086071862673209484250490600018105614048117055336074437503883703510
> 51124936122493198378815695858127594672917553146825187145285692314043598
> 45775746985748039345677748242309854210746050623711418779541821530464749
> 83581941267398767559165543946077062914571196477686542167660429831652624
> 386837205668069376 according to Mathematica)
is there a class that could store and do arithmetic on an effectively
infinite number? certainly not infinite truly, but enough so that
precision is not lost when working with numbers like 2^10^100.
~ john
On Monday, June 2, 2003, at 12:39 PM, Clark S. Cox III wrote:
> On Monday, Jun 2, 2003, at 13:28 US/Eastern, Chad Armstrong wrote:
>
>> Not exactly a Cocoa-related question, but it could be incorporated
>> into a Cocoa program. Is there a library or way to create 'big int'
>> support so a number isn't limited to the particular bounds of int,
>> float, or even an unsigned long?
>
> Check out NSDecimalNumber.
=================
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updated Jan 21 2003
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openssl (headers come with Jaguar) has a Big Number structure.
http://www.openssl.org/docs/crypto/bn.html
I've used it, for crypto stuff, but it could be useful on it's own.
-aaron
At 4:48 PM -0500 6/2/03, john gale wrote:
> would this really work, though? Here's from the documentation on_______________________________________________
> NSDecimalNumber:
>
>> NSDecimalNumber, an immutable subclass of NSNumber, provides an
>> object-oriented wrapper for doing base-10 arithmetic. An instance
>> can represent any number that can be expressed as mantissa x
>> 10^exponent where mantissa is a decimal integer up to 38 digits
>> long, and exponent is an integer from -128 through 127.
>
> hence, there wouldn't really be enough precision to detail all of
> Chad's number:
>
>> (such as 2^1000 which is equal to
>> 10715086071862673209484250490600018105614048117055336074437503883703510511249361224931983788156958581275946729175531468251871452856923140435984577574698574803934567774824230985421074605062371141877954182153046474983581941267398767559165543946077062914571196477686542167660429831652624386837205668069376
>> according to Mathematica)
>
> is there a class that could store and do arithmetic on an
> effectively infinite number? certainly not infinite truly, but
> enough so that precision is not lost when working with numbers like
> 2^10^100.
>
>
> ~ john
>
>
> On Monday, June 2, 2003, at 12:39 PM, Clark S. Cox III wrote:
>
>> On Monday, Jun 2, 2003, at 13:28 US/Eastern, Chad Armstrong wrote:
>>
>>> Not exactly a Cocoa-related question, but it could be incorporated
>>> into a Cocoa program. Is there a library or way to create 'big
>>> int' support so a number isn't limited to the particular bounds of
>>> int, float, or even an unsigned long?
>>
>> Check out NSDecimalNumber.
>
> =================
> support the arts!
> www.smadness.com
>
> updated Jan 21 2003
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