code: def test_sub(discretization):
      N = (1,)
      domain = Domain(N, dx=[1.0] * len(N))
      x = discretization.from_grid(jnp.asarray([1.0]), domain)
      y = discretization.from_grid(jnp.asarray([2.0]), domain)
  
      z = x - y
      assert z.params == -1.0
      assert type(z) == discretization
  
      @jit
      def fun(x, y):
          return x - y
  
      z = fun(x, y)
      z = fun(x, y)
      assert z.params == -1.0
      assert type(z) == discretization
  
      z = x - 2.0
      assert z.params == -1.0
  
      @jit
      def fun(x):
          return x - 2.0
  
      z = fun(x)
      z = fun(x)
      assert z.params == -1.0
  
imports: import pytest
  from jax import jit
  from jax import numpy
  from jax import random
  from jaxdf.discretization import FiniteDifferences, FourierSeries, OnGrid
  from jaxdf.geometry import Domain
  from jaxdf.operators import inverse
label_desc: Use image node_id 3 for calling a global function with example usage: test_sub(discretization) and returns: unknown, unknown