matlab中各种随机数的产生文件，其中zipf分布式自己所写

function varargout = randraw（distribName distribParams varargin）
%
%   EFFICIENT RANDOM VARIATES GENERATOR
% 
% See alphabetical list of the supported distributions below （over 50 distributions）
% 
% 1）  randraw 
%           presents general help.
% 2）  randraw（ distribName ） 
%           presents help for the specific distribution defined 
%           by usage string distribName （see table below）.
% 3）  Y = randraw（ distribName distribParams sampleSize ）;
%           returns array Y of size = sampleSize of random variates from distribName  
%           distribution with parameters distribParams
%
%               ALPHABETICAL LIST OF THE SUPPORTED DISTRIBUTIONS:
%  ____________________________________________________________________
% |      DISTRIBUTION NAME                    |   USAGE STRING         |
% |___________________________________________|________________________|
% |        Alpha                              |    ‘alpha‘             |
% |        Anglit                             |    ‘anglit‘            |
% |        Antilognormal                      |    ‘lognorm‘           |
% |        Arcsin                             |    ‘arcsin‘            |
% |        Bernoulli                          |    ‘bern‘              |
% |        Bessel                             |    ‘bessel‘            |
% |        Beta                               |    ‘beta‘              |
% |        Binomial                           |    ‘binom‘             |
% |        Bradford                           |    ‘bradford‘          |
% |        Burr                               |    ‘burr‘              |
% |        Cauchy                             |    ‘cauchy‘            |
% |        Chi                                |    ‘chi‘               |
% |        Chi-Square （Non-Central）           |    ‘chisqnc‘           |
% |        Chi-Square （Central）               |    ‘chisq‘             |
% |        Cobb-Douglas                       |    ‘lognorm‘           |
% |        Cosine                             |    ‘cosine‘            |
% |        Double-Exponential                 |    ‘laplace‘           |
% |        Erlang                             |    ‘erlang‘            |
% |        Exponential                        |    ‘exp‘               |
% |        Extreme-Value                      |    ‘extrval‘           |
% |        F （Central）                        |    ‘f‘                 |
% |        F （Non-Central）                    |    ‘fnc‘               |
% |        Fisher-Tippett                     |    ‘extrval‘           |
% |        Fisk                               |    ‘fisk‘              |
% |        Frechet                            |    ‘frechet‘           |
% |        Furry                              |    ‘furry‘             |
% |        Gamma                              |    ‘gamma‘             |
% |        Generalized Inverse Gaussian       |    ‘gig‘               |
% |        Gener