from petsc4py import PETSc

import numerical_algebra.linear_solvers as nals

import scipy.sparse as sps
import scipy.sparse.linalg as spslin

import numpy as np

import time

n = 4000


print("")
print(" First step: matrix creation")
matrix = sps.random(n, n, format='csr') + 10 * sps.eye(n) + \
        0.1j * sps.random(n, n, format='csr')

exact_solution = 0.2 * np.arange(n) + 0.01j * np.arange(n)
print(" Done...")

rhs = matrix * exact_solution

print(" Second step: solving the system of linear equations")
t0 = time.time()
x_sol = spslin.spsolve(matrix, rhs)
print(" DONE for", time.time()-t0)