qrand
Class: qrandstream
Generate quasi-random points from stream
Syntax
x = qrand(q)
X = qrand(q,n)
Description
x = qrand(q)
returns the next value x
in
the quasi-random number stream q
of the qrandstream
class. x
is
a 1-by-d vector, where d is
the dimension of the stream. The command sets q.State
to
the index in the underlying point set of the next value to be returned.
X = qrand(q,n)
returns the next n
values X
in
an n
-by-d matrix.
Objects q
of the qrandstream
class
encapsulate properties of a specified quasi-random number stream.
Values of the stream are not generated and stored in memory until q
is
accessed using qrand
.
Examples
Use qrandstream
to construct
a 3-D Halton stream, based on a point set that skips the first 1000
values and then retains every 101st point:
q = qrandstream('halton',3,'Skip',1e3,'Leap',1e2) q = Halton quasi-random stream in 3 dimensions Point set properties: Skip : 1000 Leap : 100 ScrambleMethod : none nextIdx = q.State nextIdx = 1
Use qrand
to generate two samples of size
four:
X1 = qrand(q,4) X1 = 0.0928 0.3475 0.0051 0.6958 0.2035 0.2371 0.3013 0.8496 0.4307 0.9087 0.5629 0.6166 nextIdx = q.State nextIdx = 5 X2 = qrand(q,4) X2 = 0.2446 0.0238 0.8102 0.5298 0.7540 0.0438 0.3843 0.5112 0.2758 0.8335 0.2245 0.4694 nextIdx = q.State nextIdx = 9
Use reset
to
reset the stream, then generate another sample:
reset(q) nextIdx = q.State nextIdx = 1 X = qrand(q,4) X = 0.0928 0.3475 0.0051 0.6958 0.2035 0.2371 0.3013 0.8496 0.4307 0.9087 0.5629 0.6166