EIGS Find a few eigenvalues and eigenvectors of an operator using ARPACK.
eigs(A) returns six of the largest eigenvalues of an operator.
This routine is simply a wrapper to Matlab's own EIGS routine, and
most of the argument-list variations described in Matlab's EIGS
documentation are also allowed here. The usage is identical to
Matlab's default version, except that the first argument must be a
Spot operator, and only the largest eigenvalues are considered.
Supported usage includes
D = EIGS(A)
[V,D] = EIGS(A)
[V,D,FLAG] = EIGS(A)
[V,D,FLAG] = EIGS(A,K)
[V,D,FLAG] = EIGS(A,K,SIGMA)
[V,D,FLAG] = EIGS(A,K,SIGMA,OPTS)
Again, see Matlab's built-in EIGS for details on these calls.