I am getting below error(found this in debug) while doing parallelisation using Joblib in Python.Please share the pointers for root cause and what should I do or tryout to remove this error
def multiprocess_tag(self, dfgroup, func):
print("inside multiprocess_tag_groups")
retLst = Parallel(n_jobs=(multiprocessing.cpu_count() // 2))(delayed(func)(group,
self.__class__.config)
for name, group in dfgroup)
print("after multiprocess_tag_groups")
return pd.concat(retLst)
Error
joblib.externals.loky.process_executor._RemoteTraceback:
"""
Traceback (most recent call last):
File "/simcloud-packages/venv/lib/python3.6/site-packages/joblib/externals/loky/process_executor.py", line 418, in _process_worker
r = call_item()
File "/simcloud-packages/venv/lib/python3.6/site-packages/joblib/externals/loky/process_executor.py", line 272, in __call__
return self.fn(*self.args, **self.kwargs)
File "/simcloud-packages/venv/lib/python3.6/site-packages/joblib/_parallel_backends.py", line 608, in __call__
return self.func(*args, **kwargs)
File "/simcloud-packages/venv/lib/python3.6/site-packages/joblib/parallel.py", line 256, in __call__
for func, args, kwargs in self.items]
File "/simcloud-packages/venv/lib/python3.6/site-packages/joblib/parallel.py", line 256, in <listcomp>
for func, args, kwargs in self.items]
File "/simcloud-packages/venv/lib/python3.6/site-packages/pandas/core/indexing.py", line 190, in __setitem__
self._setitem_with_indexer(indexer, value)
File "/simcloud-packages/venv/lib/python3.6/site-packages/pandas/core/indexing.py", line 605, in _setitem_with_indexer
setter(labels[0], value)
File "/simcloud-packages/venv/lib/python3.6/site-packages/pandas/core/indexing.py", line 543, in setter
self.obj[item] = s
File "/simcloud-packages/venv/lib/python3.6/site-packages/pandas/core/frame.py", line 3370, in __setitem__
self._set_item(key, value)
File "/simcloud-packages/venv/lib/python3.6/site-packages/pandas/core/frame.py", line 3446, in _set_item
NDFrame._set_item(self, key, value)
File "/simcloud-packages/venv/lib/python3.6/site-packages/pandas/core/generic.py", line 3172, in _set_item
self._data.set(key, value)
File "/simcloud-packages/venv/lib/python3.6/site-packages/pandas/core/internals/managers.py", line 1074, in set
blk.set(blk_locs, value_getitem(val_locs))
File "/simcloud-packages/venv/lib/python3.6/site-packages/pandas/core/internals/blocks.py", line 2233, in set
self.values[locs] = values
ValueError: assignment destination is read-only
"""