Python Parallel Programing

[wissam1974]

Hi Mr,
first i would like to express all my appreciation for your help.
i have followed your suggestions step by step and i modify my code so as it fit your recommendations, the new code becomes as follow:

import numpy as np
from time import time
import multiprocessing as mp

                        # Prepare data
np.random.RandomState(100)
arr = np.random.randint(0, 10, size=[200000, 5])#print(arr)
data = arr.tolist()
data[:5]
data1=[data[i] for i in range(0,1000)]
data2=[data[i] for i in range(1001,2000)]
data3=[data[i] for i in range(2001,3000)]
data4=[data[i] for i in range(3001,4000)]

                        # Define and function creation
def howmany_within_range(row, minimum, maximum):
    """Returns how many numbers lie within `maximum` and `minimum` in a given `row`"""
    count = 0
    for n in row:
        if minimum <= n <= maximum:
            count = count + 1
    return count

                        # Define funcThread
def funcThread(minimum, maximum):
    howmany_within_range(data1, minimum, maximum)
    howmany_within_range(data2, minimum, maximum)
    howmany_within_range(data3, minimum, maximum)
    howmany_within_range(data4, minimum, maximum)

                            # Block: Paralleization
        # Step 1: Init multiprocessing.Pool()
pool = mp.Pool(mp.cpu_count())
        # Step 2: `pool.apply` the `howmany_within_range()`
results = [pool.apply(funcThread, args=(4, 8))]
        # Step 3: Don't forget to close
pool.close()
pool.join()
        # Step 4: Result
print(results[:10])

the execution of my program gives the same error:

Error:
Traceback (most recent call last):
  File "<string>", line 1, in <module>
  File "C:\Users\lenovo\AppData\Local\Programs\Python\Python37\lib\multiprocessing\spawn.py", line 105, in spawn_main
    exitcode = _main(fd)
  File "C:\Users\lenovo\AppData\Local\Programs\Python\Python37\lib\multiprocessing\spawn.py", line 114, in _main
    prepare(preparation_data)
  File "C:\Users\lenovo\AppData\Local\Programs\Python\Python37\lib\multiprocessing\spawn.py", line 225, in prepare
    _fixup_main_from_path(data['init_main_from_path'])
  File "C:\Users\lenovo\AppData\Local\Programs\Python\Python37\lib\multiprocessing\spawn.py", line 277, in _fixup_main_from_path
    run_name="__mp_main__")
  File "C:\Users\lenovo\AppData\Local\Programs\Python\Python37\lib\runpy.py", line 263, in run_path
    pkg_name=pkg_name, script_name=fname)
  File "C:\Users\lenovo\AppData\Local\Programs\Python\Python37\lib\runpy.py", line 96, in _run_module_code
    mod_name, mod_spec, pkg_name, script_name)
  File "C:\Users\lenovo\AppData\Local\Programs\Python\Python37\lib\runpy.py", line 85, in _run_code
    exec(code, run_globals)
  File "C:\109_personel\113_ARIMA_Tmin\Test_3.py", line 33, in <module>
    pool = mp.Pool(mp.cpu_count())
  File "C:\Users\lenovo\AppData\Local\Programs\Python\Python37\lib\multiprocessing\context.py", line 119, in Pool
    context=self.get_context())
  File "C:\Users\lenovo\AppData\Local\Programs\Python\Python37\lib\multiprocessing\pool.py", line 176, in __init__
Traceback (most recent call last):
  File "<string>", line 1, in <module>
    self._repopulate_pool()
  File "C:\Users\lenovo\AppData\Local\Programs\Python\Python37\lib\multiprocessing\pool.py", line 241, in _repopulate_pool
  File "C:\Users\lenovo\AppData\Local\Programs\Python\Python37\lib\multiprocessing\spawn.py", line 105, in spawn_main
    w.start()
  File "C:\Users\lenovo\AppData\Local\Programs\Python\Python37\lib\multiprocessing\process.py", line 112, in start
    exitcode = _main(fd)
  File "C:\Users\lenovo\AppData\Local\Programs\Python\Python37\lib\multiprocessing\spawn.py", line 114, in _main
    self._popen = self._Popen(self)
  File "C:\Users\lenovo\AppData\Local\Programs\Python\Python37\lib\multiprocessing\context.py", line 322, in _Popen
    prepare(preparation_data)
  File "C:\Users\lenovo\AppData\Local\Programs\Python\Python37\lib\multiprocessing\spawn.py", line 225, in prepare
    return Popen(process_obj)
  File "C:\Users\lenovo\AppData\Local\Programs\Python\Python37\lib\multiprocessing\popen_spawn_win32.py", line 33, in __init__
    prep_data = spawn.get_preparation_data(process_obj._name)
  File "C:\Users\lenovo\AppData\Local\Programs\Python\Python37\lib\multiprocessing\spawn.py", line 143, in get_preparation_data
    _fixup_main_from_path(data['init_main_from_path'])
  File "C:\Users\lenovo\AppData\Local\Programs\Python\Python37\lib\multiprocessing\spawn.py", line 277, in _fixup_main_from_path
    _check_not_importing_main()
  File "C:\Users\lenovo\AppData\Local\Programs\Python\Python37\lib\multiprocessing\spawn.py", line 136, in _check_not_importing_main
    run_name="__mp_main__")
  File "C:\Users\lenovo\AppData\Local\Programs\Python\Python37\lib\runpy.py", line 263, in run_path
    is not going to be frozen to produce an executable.''')
RuntimeError: 
        An attempt has been made to start a new process before the
        current process has finished its bootstrapping phase.

        This probably means that you are not using fork to start your
        child processes and you have forgotten to use the proper idiom
        in the main module:

            if __name__ == '__main__':
                freeze_support()
                ...

        The "freeze_support()" line can be omitted if the program
        is not going to be frozen to produce an executable.
    pkg_name=pkg_name, script_name=fname)

is there other modifications or do i make something else in my code in order to solve my problem
thank you a lot Mr and your help is highly appreciated.