On 10/19/2013 01:21 AM, Phil Steitz wrote: > The decomposition solvers can "invert" non-square matrices. There > is no documentation describing what exactly is being returned in > these cases. It is not obvious to me exactly what conditions the > returned value satisfies in each case when the actual parameter is > not square. Do all of them return pseudo-inverses X satisfying AXA > = A where A is the input matrix? Do they satisfy other conditions > as well? Under what conditions will exceptions be thrown? We > should either throw NonSquareMatrixException (as MatrixUtils now > does) on non-square arguments or define precisely what is being > computed by each of the solvers for non-square arguments and what > the preconditions are.
LU and Cholesky decomposition already check if the matrix is square and throw a NonSquareMatrixException in this case. QR decomposition seems to compute the right-inverse of the matrix if the number of rows is equal to its rank. Thomas --------------------------------------------------------------------- To unsubscribe, e-mail: [email protected] For additional commands, e-mail: [email protected]
