# What is the space-complexity of the Newton-Raphson algorithm?

What's the space-complexity of Newton-Raphson? I think it reduces to the space-complexity of storing the inverse hessian matrix.

• No, because it depends on the method that you use to solve the linear system. For example, LU decomposition and Gauss-Siedel are in-place, BiCG-STAB is $O(n)$ (where $n$ is the number of variables you're solving for) if you don't use a preconditioner, and if you do use a preconditioner, then add the size of that. Aug 20 '21 at 4:44