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function data = BrownM(Npoints,Mean,std,Opt)
dt=1;
if Opt==1
    %%
%standard Brownian motion
  data=[0 cumsum(dt^0.5.*random('Normal',Mean,Std,1,Npoints))];
  figure
  plot(0:Npoints,data);
elseif Opt==2
    figure
    data=cumsum([zeros(1,3);dt^0.5*random('Normal',Mean,std,1,Npoints-1,...
        3)]);
    plot3(data(:,1),data(:,2),data(:,3),'k');
    pcol=(data-repmat(min(data),Npoints,1))./...
        repmat(max(data)-min(data),Npoints,1);
    hold on;
    scatters(data(:,1),data(:,2),data(:,3),...
        10,pcol,'filled');
    grid on;
    hold off;
else
    error('Opt=1 or Opt=2')
end

%test BrownM
clc;
Npoints = 1000;
Mean = 0;
Std = 1;
Opt = 1;
dataA = BrownM(Npoints,Mean,Std,Opt);
% Opt=2;
% dataB=BrowM(Npoints,Mean,Std,Opt);