### A Block Lanczos Method for the Linear Response Eigenvalue ...

Lanczos method for the symmetric eigenvalue problem. The associated convergence analysis shows that Tsiper’s Lanczos method may need up to twice as many Lanczos steps as the ﬁrst Lanczos method in order to reach the same accuracy. It is well known that a single-vector Lanczos method can only ﬁnd one copy of any multiple eigenvalue, and it ...