vlt.math.cov_of_cloud

  COV_OF_CLOUD - generate a cloud of gaussian points and compute covariance matrix

  [C,PTS] = vlt.math.cov_of_cloud(STD1, STD2, ROTATION, NUMPOINTS)

  Sometimes you just want to generate a cloud of gaussian points, rotate them,
  and compute the covariance matrix. You know you should be able to directly
  calculate the covariance matrix, but you have a grant due, and you've got
  to move fast.

  Example:

   [c,pts] = vlt.math.cov_of_cloud(2,0.04,1,1000);
   figure;
   subplot(2,2,1);
   plot(pts(:,1),pts(:,2),'o');
   subplot(2,2,2);
   [X,T] = meshgrid([0:0.1:10],[0:0.001:0.3]);
   Z = X * 0;
   Z = Z + reshape(mvnpdf([X(:) T(:)], mu,sigma{i}), size(X,1),size(X,2));
   pcolor(X,T,Z);
   colormap jet;
   caxis([-max(Z(:)) max(Z(:))]);
   shading flat