  We consider the finite-sum optimization problem, where each component
function is strongly convex and has Lipschitz continuous gradient and Hessian.
The recently proposed incremental quasi-Newton method is based on BFGS update
and achieves a local superlinear convergence rate that is dependent on the
condition number of the problem. This paper proposes a more efficient
quasi-Newton method by incorporating the symmetric rank-1 update into the
incremental framework, which results in the condition-number-free local
superlinear convergence rate. Furthermore, we can boost our method by applying
the block update on the Hessian approximation, which leads to an even faster
local convergence rate. The numerical experiments show the proposed methods
significantly outperform the baseline methods.
