$A$ is a $n \times n$ symmetric positive definite (SPD) sparse matrix. $G$ is a sparse diagonal matrix. $n$ is large ($n$ >10000) and the number of nonzeros in the $G$ is usually 100 ~ 1000.
$A$ has been factorized in the cholesky form as $LDL^T$.
How to update the $L$ and $D$ efficiently when $A$ becomes $A+G$?