[Index for rtools] [Return to Master Index] [Return to www.radarworks.com]

RT_weibrnd

(rtools/RT_weibrnd.m)


Function Synopsis

out = RT_weibrnd(aval,mu,mrows,ncols)

Help text

function out = RT_weibrnd(a,mu,mrows,ncols)

 Returns variates from the Weibull probability density with shape parameter A
 and mean MU.

 Note that this is not the `usual' form for the Weibull, which uses a
 non-linear scale parameter (b). For simulation, explicit definition
 in terms of the mean MU is more meaningful. For theoretical
 manipulation of equations, you're better off using b though.
 The conversion from b is MU = a^(-b) * gamma(1 + b) which is performed in
 RT_weibest.m

 A Weibull distribution in Amplitude, is also a Weibull distribution
 in Intensity. This `power law invariance' is useful for simulation, but
 it causes confusion over whether the `usual' shape parameter (c) refers
 to Amplitude _or_ Intensity in radar texts. It most often refers to Amplitude,
 but this toolbox uses Intensity as the natural measure, so check your
 conventions.

 The form used is such that the mean value is MU and larger
 A is closer to a Gaussian distribution. A = 1 is equivalent to an
 exponential distribution.

 Uses a power transform of the Exponential distribution (via RT_exprnd.m)
 If aval ~< 0.1 zeroes may be output (the dynamic range of floating point
 is not large enough). However, this value should never arise in practice.

 Source:
  [1] L. Devroye, `Non-Uniform Random Variate Generation',
   Springer-Verlag, 1986.
  [2] Direct evaluation of PDF

 Part of the Matlab Radar Toolbox v0.11 by Glen Davidson at www.radarworks.com
 Please acknowledge use of this toolbox in any publication or software.
 This header must be retained in any derivative work

Cross-Reference Information

This function calls
This function is called by

Produced by mat2html on Mon Mar 17 16:14:19 2003
Cross-Directory links are: OFF