We present an iterative method for treating extremely large-scale eigenvalu
e problems. Based on an exact formula and the GMRES method, our approach ge
nerates a subspace which has the property that the residual of interior eig
enpairs in the subspace is minimized. The result is that the corresponding
large matrix is block-diagonalized iteratively. The accuracy of the final e
igenpairs of interest is directly controlled by the accuracy of the GMRES p
rocedure. Our method limits the number of Arnoldi iterations involved, and
the dimension of the subspace, by including the residual in the subspace an
d minimizing it at each step of the iteration. (C) 1999 American Institute
of Physics. [S0021-9606(99)01516-0].