# Using ray with scipy functions

Ray allows for parallel processing and I am trying to use it with `scipy` module. I just setup `ray` and I am not sure if the behavior is expected. But anyway here is the script and the output.

``````
import math
import cmath as cm
import numpy as np
import ray

ray.init(num_cpus=6) # initializing ray here
#-----------------------------------------------------------

# DEFINE FUNCTIONS (I am not sure if i should use decorator here)

def wrap_real(r,  rho, phi):
res = cm.cos(phi)*cm.exp(-1j*2*math.pi*cm.sqrt(rho**2 +\
r**2))/cm.sqrt(rho**2 + r**2)
return res.real

def wrap_imag(r,  rho, phi):
res = cm.cos(phi)*cm.exp(-1j*2*math.pi*cm.sqrt(rho**2 + \
r**2))/cm.sqrt(rho**2 + r**2)
return res.imag

rMax = 5

# Functions called by ray
@ray.remote
def I_real (value ):
return dblquad(lambda rho, phi: wrap_real (value ,  rho, phi) \
, 0, rMax, lambda x: 0, lambda x: 2*math.pi)
@ray.remote
def I_imag (value ):
return dblquad(lambda rho, phi: wrap_imag ( value,  rho, phi) ,\
0, rMax, lambda x: 0, lambda x: 2*math.pi)
#-----------------------------------------------------------
#-----------------------------------------------------------
# TEST INTEGRATION

print("\n-----------COMPLEX INTEGRATION RESULT ----------")

run1 = I_real.remote(6)
run2 = I_imag.remote(6)

run3 = I_real.remote(6)
run4 = I_imag.remote(7)

run5 = I_real.remote(8)
run6 = I_imag.remote(10)

resultp1=ray.get([run1, run2])
resultp2=ray.get([run3, run4])
resultp3=ray.get([run5, run6])

print(resultp1)
print(resultp2)
print(resultp3)

``````

OUTPUT

``````2019-06-01 19:07:55,609 INFO node.py:497 -- Process STDOUT and STDERR is being redirected to /tmp/ray/session_2019-06-01_19-07-55_608930_25145/logs.
2019-06-01 19:07:55,713 INFO services.py:409 -- Waiting for redis server at 127.0.0.1:32983 to respond...
2019-06-01 19:07:55,846 INFO services.py:409 -- Waiting for redis server at 127.0.0.1:18737 to respond...
2019-06-01 19:07:55,847 INFO services.py:806 -- Starting Redis shard with 10.0 GB max memory.
2019-06-01 19:07:55,882 INFO node.py:511 -- Process STDOUT and STDERR is being redirected to /tmp/ray/session_2019-06-01_19-07-55_608930_25145/logs.
2019-06-01 19:07:55,883 WARNING services.py:1293 -- Warning: Capping object memory store to 20.0GB. To increase this further, specify `object_store_memory` when calling ray.init() or ray start.
2019-06-01 19:07:55,884 INFO services.py:1441 -- Starting the Plasma object store with 20.0 GB memory using /dev/shm.

-----------COMPLEX INTEGRATION RESULT ----------
2019-06-01 19:07:56,446 ERROR worker.py:1678 -- Failed to unpickle the remote function 'ques_modpy_asked_SO_modifying2.I_real' with function ID ca83a4149613ad1164353ce7183f9a21dd1da53f. Traceback:
Traceback (most recent call last):
File "/home/ankit/.local/lib/python3.6/site-packages/ray/function_manager.py", line 424, in fetch_and_register_remote_function
File "/home/ankit/Documents/confocal_vol_python/ques_modpy_asked_SO_modifying2.py", line 13, in <module>
ray.init(num_cpus=6)
File "/home/ankit/.local/lib/python3.6/site-packages/ray/worker.py", line 1351, in init
raise Exception("Perhaps you called ray.init twice by accident? "
Exception: Perhaps you called ray.init twice by accident? This error can be suppressed by passing in 'ignore_reinit_error=True' or by calling 'ray.shutdown()' prior to 'ray.init()'.

2019-06-01 19:07:56,467 ERROR worker.py:1678 -- Failed to unpickle the remote function 'ques_modpy_asked_SO_modifying2.I_real' with function ID ca83a4149613ad1164353ce7183f9a21dd1da53f. Traceback:
Traceback (most recent call last):
File "/home/ankit/.local/lib/python3.6/site-packages/ray/function_manager.py", line 424, in fetch_and_register_remote_function
File "/home/ankit/Documents/confocal_vol_python/ques_modpy_asked_SO_modifying2.py", line 13, in <module>
ray.init(num_cpus=6)
File "/home/ankit/.local/lib/python3.6/site-packages/ray/worker.py", line 1351, in init
raise Exception("Perhaps you called ray.init twice by accident? "
Exception: Perhaps you called ray.init twice by accident? This error can be suppressed by passing in 'ignore_reinit_error=True' or by calling 'ray.shutdown()' prior to 'ray.init()'.

2019-06-01 19:07:56,467 ERROR worker.py:1678 -- Failed to unpickle the remote function 'ques_modpy_asked_SO_modifying2.I_imag' with function ID b09f533dace5def97fe6c388da2e8b0be6c7d06f. Traceback:
Traceback (most recent call last):
File "/home/ankit/.local/lib/python3.6/site-packages/ray/function_manager.py", line 424, in fetch_and_register_remote_function
File "/home/ankit/Documents/confocal_vol_python/ques_modpy_asked_SO_modifying2.py", line 13, in <module>
ray.init(num_cpus=6)
File "/home/ankit/.local/lib/python3.6/site-packages/ray/worker.py", line 1351, in init
raise Exception("Perhaps you called ray.init twice by accident? "
Exception: Perhaps you called ray.init twice by accident? This error can be suppressed by passing in 'ignore_reinit_error=True' or by calling 'ray.shutdown()' prior to 'ray.init()'.

2019-06-01 19:07:56,467 ERROR worker.py:1678 -- Failed to unpickle the remote function 'ques_modpy_asked_SO_modifying2.I_imag' with function ID b09f533dace5def97fe6c388da2e8b0be6c7d06f. Traceback:
Traceback (most recent call last):
File "/home/ankit/.local/lib/python3.6/site-packages/ray/function_manager.py", line 424, in fetch_and_register_remote_function
File "/home/ankit/Documents/confocal_vol_python/ques_modpy_asked_SO_modifying2.py", line 13, in <module>
ray.init(num_cpus=6)
File "/home/ankit/.local/lib/python3.6/site-packages/ray/worker.py", line 1351, in init
raise Exception("Perhaps you called ray.init twice by accident? "
Exception: Perhaps you called ray.init twice by accident? This error can be suppressed by passing in 'ignore_reinit_error=True' or by calling 'ray.shutdown()' prior to 'ray.init()'.

2019-06-01 19:07:56,548 ERROR worker.py:1678 -- Failed to unpickle the remote function 'ques_modpy_asked_SO_modifying2.I_real' with function ID ca83a4149613ad1164353ce7183f9a21dd1da53f. Traceback:
Traceback (most recent call last):
File "/home/ankit/.local/lib/python3.6/site-packages/ray/function_manager.py", line 424, in fetch_and_register_remote_function
File "/home/ankit/Documents/confocal_vol_python/ques_modpy_asked_SO_modifying2.py", line 13, in <module>
ray.init(num_cpus=6)
File "/home/ankit/.local/lib/python3.6/site-packages/ray/worker.py", line 1351, in init
raise Exception("Perhaps you called ray.init twice by accident? "
Exception: Perhaps you called ray.init twice by accident? This error can be suppressed by passing in 'ignore_reinit_error=True' or by calling 'ray.shutdown()' prior to 'ray.init()'.

2019-06-01 19:07:56,560 ERROR worker.py:1678 -- Failed to unpickle the remote function 'ques_modpy_asked_SO_modifying2.I_imag' with function ID b09f533dace5def97fe6c388da2e8b0be6c7d06f. Traceback:
Traceback (most recent call last):
File "/home/ankit/.local/lib/python3.6/site-packages/ray/function_manager.py", line 424, in fetch_and_register_remote_function
File "/home/ankit/Documents/confocal_vol_python/ques_modpy_asked_SO_modifying2.py", line 13, in <module>
ray.init(num_cpus=6)
File "/home/ankit/.local/lib/python3.6/site-packages/ray/worker.py", line 1351, in init
raise Exception("Perhaps you called ray.init twice by accident? "
Exception: Perhaps you called ray.init twice by accident? This error can be suppressed by passing in 'ignore_reinit_error=True' or by calling 'ray.shutdown()' prior to 'ray.init()'.

2019-06-01 19:07:56,571 ERROR worker.py:1678 -- Failed to unpickle the remote function 'ques_modpy_asked_SO_modifying2.I_real' with function ID ca83a4149613ad1164353ce7183f9a21dd1da53f. Traceback:
Traceback (most recent call last):
File "/home/ankit/.local/lib/python3.6/site-packages/ray/function_manager.py", line 424, in fetch_and_register_remote_function
File "/home/ankit/Documents/confocal_vol_python/ques_modpy_asked_SO_modifying2.py", line 13, in <module>
ray.init(num_cpus=6)
File "/home/ankit/.local/lib/python3.6/site-packages/ray/worker.py", line 1351, in init
raise Exception("Perhaps you called ray.init twice by accident? "
Exception: Perhaps you called ray.init twice by accident? This error can be suppressed by passing in 'ignore_reinit_error=True' or by calling 'ray.shutdown()' prior to 'ray.init()'.

2019-06-01 19:07:56,572 ERROR worker.py:1678 -- Failed to unpickle the remote function 'ques_modpy_asked_SO_modifying2.I_imag' with function ID b09f533dace5def97fe6c388da2e8b0be6c7d06f. Traceback:
Traceback (most recent call last):
File "/home/ankit/.local/lib/python3.6/site-packages/ray/function_manager.py", line 424, in fetch_and_register_remote_function
File "/home/ankit/Documents/confocal_vol_python/ques_modpy_asked_SO_modifying2.py", line 13, in <module>
ray.init(num_cpus=6)
File "/home/ankit/.local/lib/python3.6/site-packages/ray/worker.py", line 1351, in init
raise Exception("Perhaps you called ray.init twice by accident? "
Exception: Perhaps you called ray.init twice by accident? This error can be suppressed by passing in 'ignore_reinit_error=True' or by calling 'ray.shutdown()' prior to 'ray.init()'.

2019-06-01 19:07:56,604 ERROR worker.py:1678 -- Failed to unpickle the remote function 'ques_modpy_asked_SO_modifying2.I_real' with function ID ca83a4149613ad1164353ce7183f9a21dd1da53f. Traceback:
Traceback (most recent call last):
File "/home/ankit/.local/lib/python3.6/site-packages/ray/function_manager.py", line 424, in fetch_and_register_remote_function
File "/home/ankit/Documents/confocal_vol_python/ques_modpy_asked_SO_modifying2.py", line 13, in <module>
ray.init(num_cpus=6)
File "/home/ankit/.local/lib/python3.6/site-packages/ray/worker.py", line 1351, in init
raise Exception("Perhaps you called ray.init twice by accident? "
Exception: Perhaps you called ray.init twice by accident? This error can be suppressed by passing in 'ignore_reinit_error=True' or by calling 'ray.shutdown()' prior to 'ray.init()'.

2019-06-01 19:07:56,606 ERROR worker.py:1678 -- Failed to unpickle the remote function 'ques_modpy_asked_SO_modifying2.I_imag' with function ID b09f533dace5def97fe6c388da2e8b0be6c7d06f. Traceback:
Traceback (most recent call last):
File "/home/ankit/.local/lib/python3.6/site-packages/ray/function_manager.py", line 424, in fetch_and_register_remote_function
File "/home/ankit/Documents/confocal_vol_python/ques_modpy_asked_SO_modifying2.py", line 13, in <module>
ray.init(num_cpus=6)
File "/home/ankit/.local/lib/python3.6/site-packages/ray/worker.py", line 1351, in init
raise Exception("Perhaps you called ray.init twice by accident? "
Exception: Perhaps you called ray.init twice by accident? This error can be suppressed by passing in 'ignore_reinit_error=True' or by calling 'ray.shutdown()' prior to 'ray.init()'.

2019-06-01 19:07:56,628 ERROR worker.py:1678 -- Failed to unpickle the remote function 'ques_modpy_asked_SO_modifying2.I_real' with function ID ca83a4149613ad1164353ce7183f9a21dd1da53f. Traceback:
Traceback (most recent call last):
File "/home/ankit/.local/lib/python3.6/site-packages/ray/function_manager.py", line 424, in fetch_and_register_remote_function
File "/home/ankit/Documents/confocal_vol_python/ques_modpy_asked_SO_modifying2.py", line 13, in <module>
ray.init(num_cpus=6)
File "/home/ankit/.local/lib/python3.6/site-packages/ray/worker.py", line 1351, in init
raise Exception("Perhaps you called ray.init twice by accident? "
Exception: Perhaps you called ray.init twice by accident? This error can be suppressed by passing in 'ignore_reinit_error=True' or by calling 'ray.shutdown()' prior to 'ray.init()'.

2019-06-01 19:07:56,629 ERROR worker.py:1678 -- Failed to unpickle the remote function 'ques_modpy_asked_SO_modifying2.I_imag' with function ID b09f533dace5def97fe6c388da2e8b0be6c7d06f. Traceback:
Traceback (most recent call last):
File "/home/ankit/.local/lib/python3.6/site-packages/ray/function_manager.py", line 424, in fetch_and_register_remote_function
File "/home/ankit/Documents/confocal_vol_python/ques_modpy_asked_SO_modifying2.py", line 13, in <module>
ray.init(num_cpus=6)
File "/home/ankit/.local/lib/python3.6/site-packages/ray/worker.py", line 1351, in init
raise Exception("Perhaps you called ray.init twice by accident? "
Exception: Perhaps you called ray.init twice by accident? This error can be suppressed by passing in 'ignore_reinit_error=True' or by calling 'ray.shutdown()' prior to 'ray.init()'.

Traceback (most recent call last):
File "<stdin>", line 1, in <module>
File "/home/ankit/Documents/confocal_vol_python/ques_modpy_asked_SO_modifying2.py", line 59, in <module>
resultp1=ray.get([run1, run2])
File "/home/ankit/.local/lib/python3.6/site-packages/ray/worker.py", line 2197, in get
raise value
TypeError: f() takes 0 positional arguments but 1 was given

>>> 2019-06-01 19:07:56,911     ERROR worker.py:1678 -- Failed to unpickle the remote function 'ques_modpy_asked_SO_modifying2.I_real' with function ID ca83a4149613ad1164353ce7183f9a21dd1da53f. Traceback:
Traceback (most recent call last):
File "/home/ankit/.local/lib/python3.6/site-packages/ray/function_manager.py", line 424, in fetch_and_register_remote_function
File "/home/ankit/Documents/confocal_vol_python/ques_modpy_asked_SO_modifying2.py", line 13, in <module>
ray.init(num_cpus=6)
File "/home/ankit/.local/lib/python3.6/site-packages/ray/worker.py", line 1351, in init
raise Exception("Perhaps you called ray.init twice by accident? "
Exception: Perhaps you called ray.init twice by accident? This error can be suppressed by passing in 'ignore_reinit_error=True' or by calling 'ray.shutdown()' prior to 'ray.init()'.

2019-06-01 19:07:56,911 ERROR worker.py:1678 -- Failed to unpickle the remote function 'ques_modpy_asked_SO_modifying2.I_imag' with function ID b09f533dace5def97fe6c388da2e8b0be6c7d06f. Traceback:
Traceback (most recent call last):
File "/home/ankit/.local/lib/python3.6/site-packages/ray/function_manager.py", line 424, in fetch_and_register_remote_function
File "/home/ankit/Documents/confocal_vol_python/ques_modpy_asked_SO_modifying2.py", line 13, in <module>
ray.init(num_cpus=6)
File "/home/ankit/.local/lib/python3.6/site-packages/ray/worker.py", line 1351, in init
raise Exception("Perhaps you called ray.init twice by accident? "
Exception: Perhaps you called ray.init twice by accident? This error can be suppressed by passing in 'ignore_reinit_error=True' or by calling 'ray.shutdown()' prior to 'ray.init()'.

2019-06-01 19:07:56,932 ERROR worker.py:1678 -- Failed to unpickle the remote function 'ques_modpy_asked_SO_modifying2.I_real' with function ID ca83a4149613ad1164353ce7183f9a21dd1da53f. Traceback:
Traceback (most recent call last):
File "/home/ankit/.local/lib/python3.6/site-packages/ray/function_manager.py", line 424, in fetch_and_register_remote_function
File "/home/ankit/Documents/confocal_vol_python/ques_modpy_asked_SO_modifying2.py", line 13, in <module>
ray.init(num_cpus=6)
File "/home/ankit/.local/lib/python3.6/site-packages/ray/worker.py", line 1351, in init
raise Exception("Perhaps you called ray.init twice by accident? "
Exception: Perhaps you called ray.init twice by accident? This error can be suppressed by passing in 'ignore_reinit_error=True' or by calling 'ray.shutdown()' prior to 'ray.init()'.

2019-06-01 19:07:56,933 ERROR worker.py:1678 -- Failed to unpickle the remote function 'ques_modpy_asked_SO_modifying2.I_real' with function ID ca83a4149613ad1164353ce7183f9a21dd1da53f. Traceback:
Traceback (most recent call last):
File "/home/ankit/.local/lib/python3.6/site-packages/ray/function_manager.py", line 424, in fetch_and_register_remote_function
File "/home/ankit/Documents/confocal_vol_python/ques_modpy_asked_SO_modifying2.py", line 13, in <module>
ray.init(num_cpus=6)
File "/home/ankit/.local/lib/python3.6/site-packages/ray/worker.py", line 1351, in init
raise Exception("Perhaps you called ray.init twice by accident? "
Exception: Perhaps you called ray.init twice by accident? This error can be suppressed by passing in 'ignore_reinit_error=True' or by calling 'ray.shutdown()' prior to 'ray.init()'.

2019-06-01 19:07:56,934 ERROR worker.py:1678 -- Failed to unpickle the remote function 'ques_modpy_asked_SO_modifying2.I_imag' with function ID b09f533dace5def97fe6c388da2e8b0be6c7d06f. Traceback:
Traceback (most recent call last):
File "/home/ankit/.local/lib/python3.6/site-packages/ray/function_manager.py", line 424, in fetch_and_register_remote_function
File "/home/ankit/Documents/confocal_vol_python/ques_modpy_asked_SO_modifying2.py", line 13, in <module>
ray.init(num_cpus=6)
File "/home/ankit/.local/lib/python3.6/site-packages/ray/worker.py", line 1351, in init
raise Exception("Perhaps you called ray.init twice by accident? "
Exception: Perhaps you called ray.init twice by accident? This error can be suppressed by passing in 'ignore_reinit_error=True' or by calling 'ray.shutdown()' prior to 'ray.init()'.

2019-06-01 19:07:56,945 ERROR worker.py:1678 -- Failed to unpickle the remote function 'ques_modpy_asked_SO_modifying2.I_imag' with function ID b09f533dace5def97fe6c388da2e8b0be6c7d06f. Traceback:
Traceback (most recent call last):
File "/home/ankit/.local/lib/python3.6/site-packages/ray/function_manager.py", line 424, in fetch_and_register_remote_function
File "/home/ankit/Documents/confocal_vol_python/ques_modpy_asked_SO_modifying2.py", line 13, in <module>
ray.init(num_cpus=6)
File "/home/ankit/.local/lib/python3.6/site-packages/ray/worker.py", line 1351, in init
raise Exception("Perhaps you called ray.init twice by accident? "
Exception: Perhaps you called ray.init twice by accident? This error can be suppressed by passing in 'ignore_reinit_error=True' or by calling 'ray.shutdown()' prior to 'ray.init()'.

2019-06-01 19:07:56,967 ERROR worker.py:1678 -- Failed to unpickle the remote function 'ques_modpy_asked_SO_modifying2.I_real' with function ID ca83a4149613ad1164353ce7183f9a21dd1da53f. Traceback:
Traceback (most recent call last):
File "/home/ankit/.local/lib/python3.6/site-packages/ray/function_manager.py", line 424, in fetch_and_register_remote_function
File "/home/ankit/Documents/confocal_vol_python/ques_modpy_asked_SO_modifying2.py", line 13, in <module>
ray.init(num_cpus=6)
File "/home/ankit/.local/lib/python3.6/site-packages/ray/worker.py", line 1351, in init
raise Exception("Perhaps you called ray.init twice by accident? "
Exception: Perhaps you called ray.init twice by accident? This error can be suppressed by passing in 'ignore_reinit_error=True' or by calling 'ray.shutdown()' prior to 'ray.init()'.

2019-06-01 19:07:56,968 ERROR worker.py:1678 -- Failed to unpickle the remote function 'ques_modpy_asked_SO_modifying2.I_imag' with function ID b09f533dace5def97fe6c388da2e8b0be6c7d06f. Traceback:
Traceback (most recent call last):
File "/home/ankit/.local/lib/python3.6/site-packages/ray/function_manager.py", line 424, in fetch_and_register_remote_function
File "/home/ankit/Documents/confocal_vol_python/ques_modpy_asked_SO_modifying2.py", line 13, in <module>
ray.init(num_cpus=6)
File "/home/ankit/.local/lib/python3.6/site-packages/ray/worker.py", line 1351, in init
raise Exception("Perhaps you called ray.init twice by accident? "
Exception: Perhaps you called ray.init twice by accident? This error can be suppressed by passing in 'ignore_reinit_error=True' or by calling 'ray.shutdown()' prior to 'ray.init()'.

2019-06-01 19:07:56,979 ERROR worker.py:1678 -- Failed to unpickle the remote function 'ques_modpy_asked_SO_modifying2.I_real' with function ID ca83a4149613ad1164353ce7183f9a21dd1da53f. Traceback:
Traceback (most recent call last):
File "/home/ankit/.local/lib/python3.6/site-packages/ray/function_manager.py", line 424, in fetch_and_register_remote_function
File "/home/ankit/Documents/confocal_vol_python/ques_modpy_asked_SO_modifying2.py", line 13, in <module>
ray.init(num_cpus=6)
File "/home/ankit/.local/lib/python3.6/site-packages/ray/worker.py", line 1351, in init
raise Exception("Perhaps you called ray.init twice by accident? "
Exception: Perhaps you called ray.init twice by accident? This error can be suppressed by passing in 'ignore_reinit_error=True' or by calling 'ray.shutdown()' prior to 'ray.init()'.

2019-06-01 19:07:56,979 ERROR worker.py:1678 -- Failed to unpickle the remote function 'ques_modpy_asked_SO_modifying2.I_imag' with function ID b09f533dace5def97fe6c388da2e8b0be6c7d06f. Traceback:
Traceback (most recent call last):
File "/home/ankit/.local/lib/python3.6/site-packages/ray/function_manager.py", line 424, in fetch_and_register_remote_function
File "/home/ankit/Documents/confocal_vol_python/ques_modpy_asked_SO_modifying2.py", line 13, in <module>
ray.init(num_cpus=6)
File "/home/ankit/.local/lib/python3.6/site-packages/ray/worker.py", line 1351, in init
raise Exception("Perhaps you called ray.init twice by accident? "
Exception: Perhaps you called ray.init twice by accident? This error can be suppressed by passing in 'ignore_reinit_error=True' or by calling 'ray.shutdown()' prior to 'ray.init()'.

2019-06-01 19:07:56,990 ERROR worker.py:1678 -- Failed to unpickle the remote function 'ques_modpy_asked_SO_modifying2.I_real' with function ID ca83a4149613ad1164353ce7183f9a21dd1da53f. Traceback:
Traceback (most recent call last):
File "/home/ankit/.local/lib/python3.6/site-packages/ray/function_manager.py", line 424, in fetch_and_register_remote_function
File "/home/ankit/Documents/confocal_vol_python/ques_modpy_asked_SO_modifying2.py", line 13, in <module>
ray.init(num_cpus=6)
File "/home/ankit/.local/lib/python3.6/site-packages/ray/worker.py", line 1351, in init
raise Exception("Perhaps you called ray.init twice by accident? "
Exception: Perhaps you called ray.init twice by accident? This error can be suppressed by passing in 'ignore_reinit_error=True' or by calling 'ray.shutdown()' prior to 'ray.init()'.

2019-06-01 19:07:57,000 ERROR worker.py:1678 -- Failed to unpickle the remote function 'ques_modpy_asked_SO_modifying2.I_imag' with function ID b09f533dace5def97fe6c388da2e8b0be6c7d06f. Traceback:
Traceback (most recent call last):
File "/home/ankit/.local/lib/python3.6/site-packages/ray/function_manager.py", line 424, in fetch_and_register_remote_function
File "/home/ankit/Documents/confocal_vol_python/ques_modpy_asked_SO_modifying2.py", line 13, in <module>
ray.init(num_cpus=6)
File "/home/ankit/.local/lib/python3.6/site-packages/ray/worker.py", line 1351, in init
raise Exception("Perhaps you called ray.init twice by accident? "
Exception: Perhaps you called ray.init twice by accident? This error can be suppressed by passing in 'ignore_reinit_error=True' or by calling 'ray.shutdown()' prior to 'ray.init()'.

``````

Any suggestions regarding the output.

An installation using `pip install -U ray` did it.
As mentioned in the comments by Robert, moving `ray.init()` inside `if __name__ == '__main__':` block allows for proper execution on a Windows machine.