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Last data update: 2014.03.03

R: Large sized rationals

bigq	R Documentation

Large sized rationals

Description

Class "bigq" encodes rationals encoded as ratios of arbitrary large integers (via GMP). A simple S3 class (internally a raw vector), it has been registered as formal (S4) class (via setOldClass), too.

Usage

as.bigq(n, d = 1)
## S3 method for class 'bigq'
as.character(x, b=10,...)
## S3 method for class 'bigq'
as.double(x,...)
as.bigz.bigq(a, mod=NA)
is.bigq(x)
## S3 method for class 'bigq'
is.na(x)
## S3 method for class 'bigq'
print(x, quote=FALSE, initLine = TRUE, ...)
denominator(x)
numerator(x)

Arguments

`n,d`	either integer, numeric or string value (String value: either starting with `0x` for hexadecimal, `0b` for binary or without prefix for decimal values. Any format error results in `0`). `n` stands for numerator, `d` for denominator
`a`	an element of class `"bigq"`
`mod`	optional modulus to convert into biginteger
`x`	a “rational number” (vector), of class `"bigq"`.
`b`	base: from 2 to 36
`...`	additional arguments passed to methods
`quote`	(for printing:) logical indicating if the numbers should be quoted (as characters are); the default used to be `TRUE` (implicitly) till 2011.
`initLine`	(for printing:) logical indicating if an initial line (with the class and length or dimension) should be printed.

Details

as.bigz.bigq() returns the smallest integers not less than the corresponding rationals bigq.

Value

An R object of (S3) class "bigq" representing the parameter value.

Author(s)

Antoine Lucas

References

http://mulcyber.toulouse.inra.fr/projects/gmp/

Examples

x <- as.bigq(21,6)
x
# 7 / 2
# Wow ! result is simplified.

y <- as.bigq(5,3)

# addition works !
x + y

# You can even try multiplication, division...
x * y / 13

# and, since May 2012,
x ^ 20
stopifnot(is.bigq(x), is.bigq(x + y),
	  x ^ 20 == as.bigz(7)^20 / 2^20)

# convert to string, double
as.character(x)
as.double(x)

# Depict the "S4-class" bigq, i.e., the formal (S4) methods:
if(require("Rmpfr")) # mostly interesting there
  showMethods(class="bigq")