Independent random number streams, use RandStream.Create.

STREAM = RandStream.getDefaultStream returns the default random number

stream, i.e., the one currently used by the RAND, RANDI, and RANDN

functions.

PREVSTREAM = RandStream.setDefaultStream(STREAM) returns the current default

stream, and designates the random number stream STREAM as the new default to

be used by the RAND, RANDI, and RANDN functions.

A random number stream S has properties that control its behavior. Access or

assign to a property using P = S.Property or S.Property = P.

RandStream properties:

Type - (Read-only) identifies the type of generator algorithm

used by the stream.

Seed - (Read-only) the seed value used to create the stream.

NumStreams - (Read-only) the number of streams created at the same

time as the stream.

StreamIndex - (Read-only) the stream's index among the group of streams

in which it was created.

State - the internal state of the generator. You should not depend

on the format of this property, or attempt to improvise a

property value. The value you assign to S.State must be a

value read from S.State previously. Use RESET to return a

stream to a predictable state without having previously read

from the State property.

Substream - the index of the substream to which the stream is

currently set. The default is 1. Multiple substreams are

not supported by all generator types.

RandnAlg - the current algorithm used by RANDN(S, ...) to generate

normal pseudorandom values, one of 'Ziggurat' (the

default), 'Polar', or 'Inversion'.

Antithetic - a logical value indicating whether S generates antithetic

uniform pseudorandom values, that is, the usual values

subtracted from 1. The default is false.

FullPrecision - a logical value indicating whether S generates values

using its full precision. Some generators are able to

create pseudorandom values faster, but with fewer random

bits, if FullPrecision is false. The default is true.

The sequence of pseudorandom numbers produced by a random number stream S is

determined by the internal state of its random number generator. Saving and

restoring the generator's internal state via the 'State' property allows you

to reproduce output.

Examples:

Create three independent streams:

[s1,s2,s3] = RandStream.create('mrg32k3a','NumStreams',3);

r1 = rand(s1,100000,1); r2 = rand(s2,100000,1); r3 = rand(s3,100000,1);

corrcoef([r1,r2,r3])

Create only one stream from a set of three independent streams:

s2 = RandStream.create('mrg32k3a','NumStreams',3,'StreamIndices',2);

Reset the generator for the default stream that underlies RAND, RANDI,

and RANDN back to the beginning to reproduce previous results:

reset(RandStream.getDefaultStream);

Save and restore the default stream's state to reproduce the output of

RAND:

defaultStream = RandStream.getDefaultStream;

savedState = defaultStream.State;

u1 = rand(1,5)

defaultStream.State = savedState;

u2 = rand(1,5) % contains exactly the same values as u1

Return RAND, RANDI, and RANDN to their default initial settings:

s = RandStream.create('mt19937ar','seed',5489);

RandStream.setDefaultStream(s);

Replace the default stream with a stream whose seed is based on CLOCK, so

RAND will return different values in different MATLAB sessions. NOTE: It