Eigenvalue computation by means of a tree-cotree filtering technique

Numerous attempts have been made to separate the solenoidal modes of a cavity from the irrotational ones. The methods used to date, based on the regularization of the system matrix, yield eigenvalue problems of the same dimension as the initial one, containing the same number of unwanted modes. This paper presents a technique which uses topological properties to suppress the irrotational modes. We propose its efficient implementation as a filter that acts not on the matrix directly, but rather on the input vector of a matrix-vector multiplication