code: def test_big_problem():
      n = 30
      x = np.linspace(0, 1, 5)
      y = np.zeros((2 * n, x.size))
      sol = solve_bvp(big_fun, big_bc, x, y)
  
      assert_equal(sol.status, 0)
      assert_(sol.success)
  
      sol_test = sol.sol(x)
  
      assert_allclose(sol_test[0], big_sol(x, n))
  
      f_test = big_fun(x, sol_test)
      r = sol.sol(x, 1) - f_test
      rel_res = r / (1 + np.abs(f_test))
      norm_res = (
          np.sum(np.real(rel_res * np.conj(rel_res)), axis=0) ** 0.5
      )
      assert_(np.all(norm_res < 1e-3))
  
      assert_(np.all(sol.rms_residuals < 1e-3))
      assert_allclose(sol.sol(sol.x), sol.y, rtol=1e-10, atol=1e-10)
      assert_allclose(sol.sol(sol.x, 1), sol.yp, rtol=1e-10, atol=1e-10)
  
imports: import sys
  import numpy
  from numpy.testing import assert_, assert_array_equal, assert_allclose, assert_equal
  from pytest import raises
  from scipy.sparse import coo_matrix
  from scipy.special import erf
  from scipy.integrate._bvp import modify_mesh, estimate_fun_jac, estimate_bc_jac, compute_jac_indices, construct_global_jac, solve_bvp
label_desc: Use image node_id 44 for calling a global function with example usage: test_big_problem() without return types