UpdateSeed (RandomNumberGenerator subroutine)

Reset random sequence with new salt and seed (RandomNumberGenerator class)

This method sets a random number object to the number that would be created by the New constructor with the given Seed and Salt specifications.

Syntax

randomNumberGenerator:UpdateSeed[( [Seed= string], [Salt= string])]

Syntax terms

%rand	A RandomNumberGenerator object variable.
Seed=seed	An optional, name required, argument that lets you specify a "seed" for the random number generator. If you provide no seed, the method generates a new, "random," starting value for the random number generator. seed is a string or a longstring.
Salt=salt	An optional, name required, argument that lets you specify a "salt" for the random number generator. A salt is additional data to be used (along with the explicit or default seed) to improve the randomness of the random generator's initial value. salt is a string or a longstring.

Examples

In the following request, calling updateSeed enables the production of a second series of three values of %rand that matches the initial series of three values of %rand:

begin %i is float %rand is object RandomNumberGenerator %rand = new(seed='help') for %i from 1 to 3 printtext {~} = {%rand:value} end for %rand:updateSeed(seed='help') for %i from 1 to 3 printtext {~} = {%rand:value} end for end

The result is:

%rand:value = 816969049 %rand:value = -148817379 %rand:value = 895846046 %rand:value = 816969049 %rand:value = -148817379 %rand:value = 895846046

If instead the random number is created with a salt, as in the following fragment, an updateSeed call using the salt produces a unique series of three values (salted numbers are not reproducible):

... %rand = new(salt='iou') for %i from 1 to 3 printtext {~} = {%rand:value} end for %rand:updateSeed(salt='iou') for %i from 1 to 3 printtext {~} = {%rand:value} end for

A sample result is:

%rand:value = 320947512 %rand:value = 535019615 %rand:value = -526589924 %rand:value = 387949238 %rand:value = 413468100 %rand:value = -807607538

See also

RandomNumberGenerator class	List of RandomNumberGenerator methods	RandomNumberGenerator methods syntax
Notation conventions for methods