-- | A generalized implementation for Jacobi, Gauss-Seidel, etc. All
-- that we really need to know is how to construct the matrix M, so we
-- take a function that does it as an argument.
-- | A generalized implementation for Jacobi, Gauss-Seidel, etc. All
-- that we really need to know is how to construct the matrix M, so we
-- take a function that does it as an argument.