openssl (version 0.9.3)

bignum: Big number arithmetic

Description

Basic operations for working with large integers. The bignum funtion converts a positive integer, string or raw vector into a bignum type. All basic Arithmetic and Comparison operators such as +, -, *, ^, %%, %/%, ==, !=, <, <=< code="">, > and >= are implemented for bignum objects. The https://en.wikipedia.org/wiki/Modular_exponentiation{Modular exponenent} (a^b %% m) can be calculated using bignum_mod_exp when b is too large for calculating a^b directly.

Usage

bignum(x, hex = FALSE)
bignum_mod_exp(a, b, m)

Arguments

x

an integer, string (hex or dec) or raw vector

hex

set to TRUE to parse strings as hex rather than decimal notation

a

bignum value for (a^b %% m)

b

bignum value for (a^b %% m)

m

bignum value for (a^b %% m)

Examples

# create a bignum
x <- bignum(123L)
y <- bignum("123456789123456789")
z <- bignum("D41D8CD98F00B204E9800998ECF8427E", hex = TRUE)

# Basic arithmetic
div <- z %/% y
mod <- z %% y
z2 <- div * y + mod
stopifnot(z2 == z)
stopifnot(div < z)

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