function ensemble0 = ENSEMBLE0_init(n1, n2)
% function ens0 = ensemble0(tau, n1, n2);
%
% Reads in information from INIT.mat
%
% TAU   scales the std. dev. of initial ensemble members.
% N1    is the number of non-rotated initial ensemble members
% N2    is the number of rotated initial ensemble members
%       N2 of each of 3 rotations.
% ensemble size is n1 + 6*n2
%
% Results saved in ENSEMBLE.MAT
%
global   PARAMS  TRU  
load INIT

if(~exist('n1','var')); n1 = 82; end
if(~exist('n2','var')); n2 = 3;  end

% Dimensions
Nt   = size(TRU,2);     % Number of Time Steps
Ns   = size(TRU,1);     % Number of Spatial Locations (m)


% GENERATE ENSEMBLE
% Rotation of indices for data perturbations
rot(:,1) = (1:200)';
rot(:,2) = [[100,1:99],[200,101:199]]';
rot(:,3) = [[99:100,1:98],[199:200,101:198]]';
rot(:,4) = [[98:100,1:97],[198:200,101:197]]';
rot(:,5) = [[2:100,1],[102:200,101]]';
rot(:,6) = [[3:100,1:2],[103:200,101:102]]';
rot(:,7) = [[4:100,1:3],[104:200,101:103]]';

k = 1;
for i = 1:7;
  if(i==1); 
   for j = 1:n1;
      ensemble0(:,k) = TRU(:,1);
      k = k+1;
   end
  else
   for j = 1:n2
      ensemble0(:,k) = TRU(rot(:,i),1);
      k = k+1;
   end
  end
end
Nens = size(ensemble0,2);
ensemble0 = ensemble0 + tau*Omgc*randn(size(ensemble0));

%save INIT ensemble0 Nens -append;

%clear rot i j k