gauss_mixture.m

著名的seismiclab的代码 是地震学研究人员必备的工具

function [r] = gauss_mixture(N,seed,p,sigma1,sigma2);
%GAUSS_MIXTURE: Compute a reflectivity series
%               using a gaussian mixture
%
% [r] = gauss_mixture(N,seed,p,sigma1,sigma2);
%
%  IN     N:      mumber of samples
%         seed:   seed to start the RN generator 
%         p:      mixing paramter p\in[0,1]
%         sigma1: variance of distribution with probability p
%         sigma2: variance of distribution with probability 1-p
%
%  OUT    r:     randon relfectivity
%
%
%  Example:
%           N = 200; p = 0.8; sigma1 = 0.01; sigma2 = 1;
%           [r] = gauss_mixture(N,1,p,sigma1,sigma2); plot(r);           
%
%  SeismicLab
%  Version 1
%
%  written by M.D.Sacchi, last modified December 10,  1998.
%  [e-mail] 
%
%  Copyright (C) 2001 Seismic Processing and Imaging Group
%                     Department of Physics
%                     The University of Alberta
%

rand('state',seed);
randn('state',7*seed);

r1 = randn(N,1)*sqrt(sigma1);
r2 = randn(N,1)*sqrt(sigma2);

for k=1:N
  if rand(1,1) < p; r(k)=r1(k); else
                    r(k)=r2(k); end;
end