title: Need help in solving a sparse system in python; spsolve with Numba
body: <p>I have a sparse system Ax=b, provided that the Matrices are in csr format. I want to speed it up using Numba. But I get an error, TypeError: return type must be specified for object mode. I got an idea that spsolve can not be applied in Numba but is there any other alternative to speed up the sparse system?
  I am using the reference from <a href="https://stackoverflow.com/questions/65186861/how-to-use-numba-to-speed-up-spsolve">How to use numba to speed up spsolve?</a>, but still, it is not clear to me.
  Any help is appreciated!</p>