Ruby

#if 0

/* BigDecimal provides arbitrary-precision floating point decimal arithmetic.

*

* Copyright (C) 2002 by Shigeo Kobayashi <shigeo@tinyforest.gr.jp>.

* You may distribute under the terms of either the GNU General Public

* License or the Artistic License, as specified in the README file

* of the BigDecimal distribution.

*

* Documented by mathew <meta@pobox.com>.

*

* = Introduction

*

* Ruby provides built-in support for arbitrary precision integer arithmetic.

* For example:

*

* 42**13 -> 1265437718438866624512

*

* BigDecimal provides similar support for very large or very accurate floating

* point numbers.

*

* Decimal arithmetic is also useful for general calculation, because it

* provides the correct answers people expect--whereas normal binary floating

* point arithmetic often introduces subtle errors because of the conversion

* between base 10 and base 2. For example, try:

*

* sum = 0

* for i in (1..10000)

* sum = sum + 0.0001

* end

* print sum

*

* and contrast with the output from:

*

* require 'bigdecimal'

*

* sum = BigDecimal.new("0")

* for i in (1..10000)

* sum = sum + BigDecimal.new("0.0001")

* end

* print sum

*

* Similarly:

*

* (BigDecimal.new("1.2") - BigDecimal("1.0")) == BigDecimal("0.2") -> true

*

* (1.2 - 1.0) == 0.2 -> false

*

* = Special features of accurate decimal arithmetic

*

* Because BigDecimal is more accurate than normal binary floating point

* arithmetic, it requires some special values.

*

* == Infinity

*

* BigDecimal sometimes needs to return infinity, for example if you divide

* a value by zero.

*

* BigDecimal.new("1.0") / BigDecimal.new("0.0") -> infinity

*

* BigDecimal.new("-1.0") / BigDecimal.new("0.0") -> -infinity

*

* You can represent infinite numbers to BigDecimal using the strings

* 'Infinity', '+Infinity' and '-Infinity' (case-sensitive)

*

* == Not a Number

*

* When a computation results in an undefined value, the special value NaN

* (for 'not a number') is returned.

*

* Example:

*

* BigDecimal.new("0.0") / BigDecimal.new("0.0") -> NaN

*

* You can also create undefined values. NaN is never considered to be the

* same as any other value, even NaN itself:

*

* n = BigDecimal.new('NaN')

*

* n == 0.0 -> nil

*

* n == n -> nil

*

* == Positive and negative zero

*

* If a computation results in a value which is too small to be represented as

* a BigDecimal within the currently specified limits of precision, zero must

* be returned.

*

* If the value which is too small to be represented is negative, a BigDecimal

* value of negative zero is returned. If the value is positive, a value of

* positive zero is returned.

*

* BigDecimal.new("1.0") / BigDecimal.new("-Infinity") -> -0.0

*

* BigDecimal.new("1.0") / BigDecimal.new("Infinity") -> 0.0

*

* (See BigDecimal.mode for how to specify limits of precision.)

*

* Note that -0.0 and 0.0 are considered to be the same for the purposes of

* comparison.

*

* Note also that in mathematics, there is no particular concept of negative

* or positive zero; true mathematical zero has no sign.

*/

void

Init_BigDecimal()

{

/* This is a #if-ed out function to fool Rdoc into documenting the class. */

/* The real init function is Init_bigdecimal() further down. */

}

#endif