docstr: tests if the modf function works
docstr_tok: ["tests","if","the","modf","function","works"]
code: def test_modf(self):
      """tests if the modf function works"""
      for s in sizes:
          a = gpuarray.arange(s, dtype=np.float32) / 10
          fracpart, intpart = cumath.modf(a)
  
          a = a.get()
          intpart = intpart.get()
          fracpart = fracpart.get()
  
          for i in range(s):
              fracpart_true, intpart_true = math.modf(a[i])
  
              assert intpart_true == intpart[i]
              assert abs(fracpart_true - fracpart[i]) < 1e-4
  
file_path: pycuda/test/test_cumath.py
imports: import math
  import numpy
  from pycuda.tools import mark_cuda_test
  import pycuda.gpuarray
  import pycuda.driver
  import pycuda.cumath
label_desc: Use image node_id 3 for calling the TestMath obj's underlying member method code with example usage: obj.test_modf() without return types