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Usage
vtkMinimalStandardRandomSequence is a sequence of
statistically independent pseudo random numbers uniformly
distributed between 0.0 and 1.0.
The sequence is generated by a prime modulus multiplicative
linear congruential generator (PMMLCG) or "Lehmer generator"
with multiplier 16807 and prime modulus 2^(31)-1. The
authors calls it "minimal standard random number generator"
ref: "Random Number Generators: Good Ones are Hard to Find,"
by Stephen K. Park and Keith W. Miller in Communications of
the ACM, 31, 10 (Oct. 1988) pp. 1192-1201. Code is at page
1195, "Integer version 2"
Correctness test is described in first column, page 1195: A
seed of 1 at step 1 should give a seed of 1043618065 at step
10001.
To create an instance of class
vtkMinimalStandardRandomSequence, simply invoke its
constructor as follows
obj = vtkMinimalStandardRandomSequence
Methods
The class vtkMinimalStandardRandomSequence has several
methods that can be used. They are listed below. Note that
the documentation is translated automatically from the VTK
sources, and may not be completely intelligible. When in
doubt, consult the VTK website. In the methods listed below,
obj is an instance of the vtkMinimalStandardRandomSequence
class.
* string = obj.GetClassName ()
* int = obj.IsA (string name)
* vtkMinimalStandardRandomSequence = obj.NewInstance ()
* vtkMinimalStandardRandomSequence = obj.SafeDownCast
(vtkObject o)
* obj.SetSeed (int value) - Set the seed of the random
sequence. The following pre-condition is stated page 1197,
second column: valid_seed: value>=1 &&
value<=2147483646 2147483646=(2^31)-2 This method does not
have this criterium as a pre-condition (ie it will not
fail if an incorrect seed value is passed) but the value
is silently changed to fit in the valid range
[1,2147483646]. 2147483646 is added to a null or negative
value. 2147483647 is changed to be 1 (ie 2147483646 is
substracted). Implementation note: it also performs 3
calls to Next() to avoid the bad property that the first
random number is proportional to the seed value.
* obj.SetSeedOnly (int value) - Set the seed of the random
sequence. There is no extra internal ajustment. Only
useful for writing correctness test. The following pre-
condition is stated page 1197, second column 2147483646=
(2^31)-2 This method does not have this criterium as a
pre-condition (ie it will not fail if an incorrect seed
value is passed) but the value is silently changed to fit
in the valid range [1,2147483646]. 2147483646 is added to
a null or negative value. 2147483647 is changed to be 1
(ie 2147483646 is substracted).
* int = obj.GetSeed () - Get the seed of the random
sequence. Only useful for writing correctness test.
* double = obj.GetValue () - Current value
Postcondition:
unit_range: result>=0.0 && result<=1.0
* obj.Next () - Move to the next number in the random
sequence.
* double = obj.GetRangeValue (double rangeMin, double
rangeMax) - Convenient method to return a value in a
specific range from the range [0,1. There is an initial
implementation that can be overridden by a subclass. There
is no pre-condition on the range:
o it can be in increasing order: rangeMin<rangeMax
o it can be empty: rangeMin=rangeMax
o it can be in decreasing order: rangeMin>rangeMax
Postcondition:
result_in_range: (rangeMin<=rangeMax &&
result>=rangeMin && result<=rangeMax) ||
(rangeMax<=rangeMin && result>=rangeMax
&& result<=rangeMin)
* FreeMat_Documentation
* Visualization_Toolkit_Common_Classes
* Generated on Thu Jul 25 2013 17:18:30 for FreeMat by
doxygen_ 1.8.1.1
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