igraph (version 0.7.1)

srand: Set random seed of the C library's RNG

Description

Set the random seed of the C library's RNG, for a new sequence of pseudo-random numbers.

Usage

srand(seed)

Arguments

seed

Numeric scalar, the new random seed. It must be non-negative and will be converted to an integer.

Value

• NULL, invisibly.

Details

Note that this function has nothing to do with R's random number generator, see set.seed for that.

Some package (e.g. ngspatial) use internal C code and generate random numbers using the standard C library's built-in random number generator instead of using R's RNGs. The srand function is provided to set the random seed for these packages. It simply calls the standard C function srand, with the supplied integer seed value.

Note that the standard C library's RNGs are typically of very bad quality, and also slower than R's RNGs. It is not worth using them, really, other than taking over some legacy C code that already uses them, and that would be difficult to rewrite to use R's RNGs.