365. INVALID @EIGEN USAGE.

The @EIGEN function returns eigenvectors and eigenvalues for the matrix A. The syntax for @EIGEN is:

LAMDAR, VR, LAMBDAI, VI, err = @EIGEN( A);

where,

•A                a nxn matrix
•LAMBDAR        a vector of length n for returning the real parts of the eigenvalues
•VR                a nxn matrix for returning the real parts of the eigenvectors (one vector per column),
•LAMBDAI        a vector of length n for returning the imaginary parts of the eigenvalues,
•VI                a nxn matrix for returning the imaginary parts of the eigenvectors, and
•err                an error flag that will be 1 if a numeric problem occurs, otherwise 0.

All matrices must be dense and cannot be defined on sparse sets, and @EIGEN may only be used in a model's calc section.

As long as at least one left-hand side argument is present, all other arguments may be omitted.  If err is present, then LINGO will not halt the run if a numeric error occurs; it will be up to your model to handle the error.  If err is not present and a numeric error occurs, then LINGO will halt model execution.

For more information, refer to the section Matrix Functions.