[A2,B2]=findnear(Dist,A1,na,B1,nb,n1)

function [A2,B2]=findnear(Dist,A1,na,B1,nb,n1)
% finding nearest elements between two groups A1 and B1
% A2 in A1 contains nearest elements near B1
% Dist - distance matrix, 0 is the smallest value

A2=[];
B2=[];
for i=1:100
  [c,ra]=min(Dist(A1,B1));
  [c,ia]=sort(c);
  for j=1:length(B1)
   c=ra(ia);
   c=unique(c);
   L=length(c);
   if L==na 
    break; 
   elseif L>na
    ia=ia(1:length(ia)-L+na);
   elseif L<na 
    if j==1 
        break; 
    end
    ia=ia(1:length(ia)+1);
   end
  end
  if length(A1)==1 
      c=1; 
  end
  A2=[A2;A1(c)];
  if L>=na 
      break; 
  end
  A1=setdiff(A1,A1(c));
  na=na-L;
end

if n1==1 
    return; 
end

for i=1:100
  [c,rb]=min(Dist(B1,A1));
  [c,ib]=sort(c);
  for j=1:length(A1)
   c=rb(ib);
   c=unique(c);
   L=length(c);
  if L==nb 
    break; 
  elseif L>nb
    ib=ib(1:length(ib)-L+nb);
   elseif L<nb 
    if j==1 
        break; 
    end
    ib=ib(1:length(ib)+1);
  end
  end
  if length(B1)==1 
      c=1; 
  end
  B2=[B2;B1(c)];
  if L>=nb 
      break; 
  end
  B1=setdiff(B1,B1(c));
  nb=nb-L;
end