# Random numbers¶

## Simple interface¶

RandomSeed(seed)

seed the global pseudo-random generator

Random()

generate pseudo-random number

Random() generates a uniformly-distributed pseudo-random number between 0 and 1.

RngCreate()
RngCreate(seed)
RngCreate([seed=seed][, engine=engine][, dist=dist])
RngCreate({seed, engine, dist})

create a pseudo-random generator

RngCreate() returns a list which is a well-formed RNG object. Its value should be saved in a variable and used to call Rng() and RngSeed().

Engines:

• default

• advanced

Distributions:

• default (the same as flat)

• flat (uniform)

• gauss (normal)

RngSeed(r, seed)

(re)seed pseudo-random number generator

RngSeed() re-initializes the RNG object r with the seed value seed. The seed value should be a positive integer.

Rng(r)

generate pseudo-random number

Rng(r)() returns a floating-point random number between 0 and 1 and updates the RNG object r. (Currently, the Gaussian option makes a RNG return a complex random number instead of a real random number.)

## Auxilliary functions¶

RandomIntegerMatrix(rows, cols, from, to)

generate a matrix of random integers

This function generates a rows x cols matrix of random integers. All entries lie between from and to, including the boundaries, and are uniformly distributed in this interval.

Example

In> PrettyForm( RandomIntegerMatrix(5,5,-2^10,2^10) )
/                                               \
| ( -506 ) ( 749 )  ( -574 ) ( -674 ) ( -106 )  |
|                                               |
| ( 301 )  ( 151 )  ( -326 ) ( -56 )  ( -277 )  |
|                                               |
| ( 777 )  ( -761 ) ( -161 ) ( -918 ) ( -417 )  |
|                                               |
| ( -518 ) ( 127 )  ( 136 )  ( 797 )  ( -406 )  |
|                                               |
| ( 679 )  ( 854 )  ( -78 )  ( 503 )  ( 772 )   |
\                                               /

RandomIntegerVector(n, from, to)

generate a vector of random integers

This function generates a list with n random integers. All entries lie between from and to, including the boundaries, and are uniformly distributed in this interval.

Example

In> RandomIntegerVector(4,-3,3)
Out> {0,3,2,-2};


RandomPoly(var, deg, coefmin, coefmax)

construct a random polynomial

RandomPoly() generates a random polynomial in the variable var, of degree deg, with integer coefficients ranging from coefmin to coefmax (inclusive). The coefficients are uniformly distributed in this interval, and are independent of each other.

Example

In> RandomPoly(x,3,-10,10)
Out> 3*x^3+10*x^2-4*x-6;
In> RandomPoly(x,3,-10,10)
Out> -2*x^3-8*x^2+8;