Using the GUI with Sparse matrices Using the GUI with Sparse matrices See also Using the GUI with Dense Matrices . The software can be downloaded here . Since this is generally very much smaller than the size of the original matrix, computations within the GUI are generally much quicker than equivalent computations with the original matrix. The GUI is started automatically after an eigs computation by default.
Several parameters are available to control the initial look of the pseudospectra computed.
They are listed below, along with their default values. Any options used should be passed to the eigs command in the same structure as usual. Full documentation of the operation of the GUI once it has been started is also available. In addition to the above method using eigs , the GUI can also compute the pseudospectra of sparse matrices directly. The time required is roughly proportional to the product of the time taken to perform a sparse LU decomposition of the matrix and the total number of gridpoints.