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# wraylrnd

## PURPOSE

Random matrices from a Rayleigh distribution

## SYNOPSIS

R = wraylrnd(b,varargin);

## DESCRIPTION

``` WRAYLRND Random matrices from a Rayleigh distribution

CALL:  R = wraylrnd(b,sz)

R = matrix of random numbers
b = parameter
sz = size(R)    (Default size(b))
sz can be a comma separated list or a vector
giving the size of R (see zeros for options).

The Rayleigh distribution is defined by its cdf

F(x;b) = 1 - exp(-x^2/(2b^2)), x>=0

The random numbers are generated by the inverse method.

Example:
R=wraylrnd(2,1,100);
wraylplot(R);

## CROSS-REFERENCE INFORMATION

This function calls:
 comnsize Check if all input arguments are either scalar or of common size. wraylinv Inverse of the Rayleigh distribution function error Display message and abort function.
This function is called by:
 dist2drnd Random points from a bivariate DIST2D distribution kdedemo2 Demonstrate the difference between transformation- and ordinary-KDE mdist2drnd Random points from a bivariate MDIST2D distribution

## SOURCE CODE

```001 function R = wraylrnd(b,varargin);
002 %WRAYLRND Random matrices from a Rayleigh distribution
003 %
004 % CALL:  R = wraylrnd(b,sz)
005 %
006 %        R = matrix of random numbers
007 %        b = parameter
008 %       sz = size(R)    (Default size(b))
009 %            sz can be a comma separated list or a vector
010 %            giving the size of R (see zeros for options).
011 %
012 % The Rayleigh distribution is defined by its cdf
013 %
014 %  F(x;b) = 1 - exp(-x^2/(2b^2)), x>=0
015 %
016 % The random numbers are generated by the inverse method.
017 %
018 % Example:
019 %   R=wraylrnd(2,1,100);
020 %   wraylplot(R);
021 %
023
024 % Reference: Cohen & Whittle, (1988) "Parameter Estimation in Reliability
025 % and Life Span Models", p. 181 ff, Marcel Dekker.
026
027
028 % Tested on: Matlab 5.3
029 % History:
030 % revised PJ 03-Apr-2001
031 %  - added comnsize, nargchk
032 %  - made sizing of R more flexible
033 % revised jr 22.11.2000
034 % - 'reshape' introduced to obtain wanted dimension of output
035 % added ms 15.06.2000
036
037 error(nargchk(1,inf,nargin))
038 if nargin>1,
039  [errorcode b]=comnsize(b,zeros(varargin{:}));
040  if errorcode
041    error('b must be a scalar or comply to the size info given.');
042  end
043 end
044
045 %if nargin==1,
046 % m=1;n=1;
047 %end
048
049 R = wraylinv(rand(size(b)),b);
050 %R = reshape(wraylinv(rand(m,n),b),m,n);
051
052```

Mathematical Statistics
Centre for Mathematical Sciences
Lund University with Lund Institute of Technology

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