10.6 Random Numbers

Function: make_random_state
    make_random_state (n)
    make_random_state (s)
    make_random_state (true)
    make_random_state (false) ¶

A random state object represents the state of the random number generator. The state comprises 627 32-bit words.

make_random_state (n) returns a new random state object created from an integer seed value equal to n modulo 2^32. n may be negative.

make_random_state (s) returns a copy of the random state s.

make_random_state (true) returns a new random state object, using the current computer clock time as the seed.

make_random_state (false) returns a copy of the current state of the random number generator.

Categories: Random numbers ·

Function: set_random_state (s) ¶

Copies s to the random number generator state.

set_random_state always returns done.

Categories: Random numbers ·

Function: random (x) ¶

Returns a pseudorandom number. If x is an integer, random (x) returns an integer from 0 through x - 1 inclusive. If x is a floating point number, random (x) returns a nonnegative floating point number less than x. random complains with an error if x is neither an integer nor a float, or if x is not positive.

The functions make_random_state and set_random_state maintain the state of the random number generator.

The Maxima random number generator is an implementation of the Mersenne twister MT 19937.

Examples:

(%i1) s1: make_random_state (654321)$

(%i2) set_random_state (s1);
(%o2)                         done

(%i3) random (1000);
(%o3)                          768

(%i4) random (9573684);
(%o4)                        7657880

(%i5) random (2^75);
(%o5)                11804491615036831636390

(%i6) s2: make_random_state (false)$

(%i7) random (1.0);
(%o7)                  0.2310127244107132

(%i8) random (10.0);
(%o8)                   4.394553645870825

(%i9) random (100.0);
(%o9)                   32.28666704056853

(%i10) set_random_state (s2);
(%o10)                        done

(%i11) random (1.0);
(%o11)                 0.2310127244107132

(%i12) random (10.0);
(%o12)                  4.394553645870825

(%i13) random (100.0);
(%o13)                  32.28666704056853

Categories: Random numbers · Numerical methods ·