circle_map, a MATLAB code which illustrates how a matrix maps points on the unit circle to an ellipse.
The computer code and data files described and made available on this web page are distributed under the GNU LGPL license.
circle_map is available in a MATLAB version.
svd_circle, a MATLAB code which analyzes a linear map of the unit circle caused by an arbitrary 2x2 matrix A, using the singular value decomposition.