function [Y, X, Yt] = GetDat(n,sig)
try load Lmembrain,
catch
  DIM=500;
  d = DIM/2;
  left = reshape(1:2*d^2,2*d,d);
  ne = zeros(d,d);
  se = reshape(2*d^2+1:3*d^2,d,d);
  right = [ne; se];
  L1 = [left, right];
  [m,n] = size(L1);
  L2 = [zeros(m,1), L1, zeros(m,1)];
  L = [zeros(1,n+2); L2; zeros(1,n+2)];
  A = delsq(L);
  spy(A);
  opts.disp = 0;
  [vecs,vals] = eigs(A,6,'sm',opts);
  v = vecs(:,end);  % Grab the last column.
  L(find(L)) = v;
%  s = surf(-L);
%  imagesc(-L);
  save Lmembrain L
end
  
DIM=size(L);

X = rand(n,2);  
Y = interp2(1:DIM(1),1:DIM(2),-L,X(:,1)*DIM(1),X(:,2)*DIM(2));
Y(isnan(Y)) = 0;
Y = (Y-mean(Y(:)))/std(Y(:));
Yt = Y;
if sig>0
  Yn = Y+sig*randn(size(Y));
  Y = (Yn-mean(Yn(:)))/std(Yn(:));
  Yt = (Yt-mean(Yn(:)))/std(Yn(:));
end