What programming languages support arbitrary precision arithmetic?

Question

What programming languages support arbitrary precision arithmetic and could you give a short example of how to print an arbitrary number of digits?

Answer 1

Java natively can do bignum operations with BigDecimal. GMP is the defacto standard library for bignum with C/C++.

Answer 2

Python has such ability. There is an excellent example here: http://tinyurl.com/python-precision

From the article:

from math import log as _flog

def log(x):
    if x < 0:
        return Decimal("NaN")
    if x == 0:
        return Decimal("-inf")
    getcontext().prec += 3
    eps = Decimal("10")**(-getcontext().prec+2)
    # A good initial estimate is needed
    r = Decimal(repr(_flog(float(x))))
    while 1:
        r2 = r - 1 + x/exp(r)
        if abs(r2-r) < eps:
            break
        else:
            r = r2
    getcontext().prec -= 3
    return +r

Also, the python quick start tutorial discusses the arbitrary precision: http://docs.python.org/lib/decimal-tutorial.html

and describes getcontext:

the getcontext() function accesses the current context and allows the settings to be changed.

Edit: Made tinyurl link to get past the dead link problem. Added clarification on getcontext.

Answer 3

In Common Lisp,

(format t "~D~%" (expt 7 77))

"~D~%" in printf format would be "%d\n". Arbitrary precision arithmetic is built into Common Lisp.

Answer 4

Some languages have this support built in. For example, take a look at java.math.BigDecimal in Java, or decimal.Decimal in Python.

Other languages frequently have a library available to provide this feature. For example, in C you could use GMP or other options.

The "Arbitrary-precision software" section of this article gives a good rundown of your options.

Answer 5

Many people recommended Python's decimal module, but I would recommend using mpmath over decimal for any serious numeric uses.

Answer 6

Scheme (a variation of lisp) has a capability called 'bignum'. there are many good scheme implementations available both full language environments and embeddable scripting options. a few I can vouch for

MitScheme (also referred to as gnu scheme) PLTScheme Chezscheme Guile (also a gnu project) Scheme 48

Answer 7

If you want to work in the .NET world you can use still use the java.math.BigDecimal class. Just add a reference to vjslib (in the framework) and then you can use the java classes.

The great thing is, they can be used fron any .NET language. For example in C#:

    using java.math;

    namespace MyNamespace
    {
        class Program
        {
            static void Main(string[] args)
            {
                BigDecimal bd = new BigDecimal("12345678901234567890.1234567890123456789");

                Console.WriteLine(bd.ToString());
            }
        }
    }

Answer 8

COBOL

77 VALUE PIC S9(4)V9(4).

a signed variable witch 4 decimals.

PL/1

DCL VALUE DEC FIXED (4,4);

:-) I can't remember the other old stuff...

Jokes apart, as my example show, I think you shouldn't choose a programming language depending on a single feature. Virtually all decent and recent language support fixed precision in some dedicated classes.

Answer 9

Mathematica.

N[Pi, 100]

3.141592653589793238462643383279502884197169399375105820974944592307816406286208998628034825342117068

Not only does mathematica have arbitrary precision but by default it has infinite precision. It keeps things like 1/3 as rationals and even expressions involving things like Sqrt[2] it maintains symbolically until you ask for a numeric approximation, which you can have to any number of decimal places.

Answer 10

Apparently Tcl also has them, from version 8.5, courtesy of LibTomMath:

http://wiki.tcl.tk/5193
http://www.tcl.tk/cgi-bin/tct/tip/237.html
http://math.libtomcrypt.com/