Scikit-Learn no logging output for transformers in FeatureUnion when n_jobs != 1












0














Using a FeatureUnion with some custom transformers I noticed that some output wasn't showing up in my terminal that I was expecting from logger.info() statements within the transformers. After digging around, I was able to track it down to the FeatureUnion's n_jobs parameter. If it is not set to n_jobs=1 output from loggers will not show up. However, output from regular print() statements does show up.



MWE



import logging
import numpy as np
from sklearn.pipeline import FeatureUnion
from sklearn.preprocessing import MinMaxScaler

logger = logging.getLogger(__name__)
logging.basicConfig(level=logging.INFO)


class MyMinMaxScaler(MinMaxScaler):
def fit(self, X, y=None):
logger.info("fitting MyMinMaxScaler")
print("fitting MyMinMaxScaler")
super().fit(X, y)


fu = FeatureUnion(
[("myscaler", MyMinMaxScaler()),
("regular_scaler", MinMaxScaler())],
n_jobs=-1
)

data = np.array([40, 41, 42]).reshape(-1, 1)
fu.fit(data)
logger.info(fu.transform(data))


Output n_jobs=-1



fitting MyMinMaxScaler
INFO:__main__:[[0. ]
[0.5]
[1. ]]


Output n_jobs=1



INFO:__main__:fitting MyMinMaxScaler
fitting MyMinMaxScaler
INFO:__main__:[[0. ]
[0.5]
[1. ]]


I wonder if this is the intended behavior. I was thinking this may be related to multiprocessing and output from child processes not showing up. But why would regular print() statements work as usual and logging output would not?



This behavior, at first, let me believe that my transformers weren't actually being fitted and thus not used at all. It's obviously not a big deal now that I know that the transformers are being used as expected. I would, however, appreciate some insight into why this logging behavior may occur the way it does, and if there is any way around it.










share|improve this question
























  • How are you executing this? From an IDE or in terminal? If from an IDE, you will not get the output. If that ide is in turn started through terminal, then you will get the output on that actual terminal, instead of output space of IDE.
    – Vivek Kumar
    Nov 26 '18 at 14:43










  • I execute this in a terminal. I use and IDE only as a code editor.
    – pmlk
    Nov 26 '18 at 17:14










  • Can't reproduce - I see the log output you're not seeing with n_jobs=-1. CPython 3.6.3, scikit-learn 0.19.0.
    – user2357112
    Dec 11 '18 at 18:23










  • Can reproduce on scikit-learn 0.20.1. Something must have changed between those versions.
    – user2357112
    Dec 11 '18 at 18:24










  • print(logger) shows that the logger's level is WARNING instead of INFO inside fit.
    – user2357112
    Dec 11 '18 at 18:29
















0














Using a FeatureUnion with some custom transformers I noticed that some output wasn't showing up in my terminal that I was expecting from logger.info() statements within the transformers. After digging around, I was able to track it down to the FeatureUnion's n_jobs parameter. If it is not set to n_jobs=1 output from loggers will not show up. However, output from regular print() statements does show up.



MWE



import logging
import numpy as np
from sklearn.pipeline import FeatureUnion
from sklearn.preprocessing import MinMaxScaler

logger = logging.getLogger(__name__)
logging.basicConfig(level=logging.INFO)


class MyMinMaxScaler(MinMaxScaler):
def fit(self, X, y=None):
logger.info("fitting MyMinMaxScaler")
print("fitting MyMinMaxScaler")
super().fit(X, y)


fu = FeatureUnion(
[("myscaler", MyMinMaxScaler()),
("regular_scaler", MinMaxScaler())],
n_jobs=-1
)

data = np.array([40, 41, 42]).reshape(-1, 1)
fu.fit(data)
logger.info(fu.transform(data))


Output n_jobs=-1



fitting MyMinMaxScaler
INFO:__main__:[[0. ]
[0.5]
[1. ]]


Output n_jobs=1



INFO:__main__:fitting MyMinMaxScaler
fitting MyMinMaxScaler
INFO:__main__:[[0. ]
[0.5]
[1. ]]


I wonder if this is the intended behavior. I was thinking this may be related to multiprocessing and output from child processes not showing up. But why would regular print() statements work as usual and logging output would not?



This behavior, at first, let me believe that my transformers weren't actually being fitted and thus not used at all. It's obviously not a big deal now that I know that the transformers are being used as expected. I would, however, appreciate some insight into why this logging behavior may occur the way it does, and if there is any way around it.










share|improve this question
























  • How are you executing this? From an IDE or in terminal? If from an IDE, you will not get the output. If that ide is in turn started through terminal, then you will get the output on that actual terminal, instead of output space of IDE.
    – Vivek Kumar
    Nov 26 '18 at 14:43










  • I execute this in a terminal. I use and IDE only as a code editor.
    – pmlk
    Nov 26 '18 at 17:14










  • Can't reproduce - I see the log output you're not seeing with n_jobs=-1. CPython 3.6.3, scikit-learn 0.19.0.
    – user2357112
    Dec 11 '18 at 18:23










  • Can reproduce on scikit-learn 0.20.1. Something must have changed between those versions.
    – user2357112
    Dec 11 '18 at 18:24










  • print(logger) shows that the logger's level is WARNING instead of INFO inside fit.
    – user2357112
    Dec 11 '18 at 18:29














0












0








0


0





Using a FeatureUnion with some custom transformers I noticed that some output wasn't showing up in my terminal that I was expecting from logger.info() statements within the transformers. After digging around, I was able to track it down to the FeatureUnion's n_jobs parameter. If it is not set to n_jobs=1 output from loggers will not show up. However, output from regular print() statements does show up.



MWE



import logging
import numpy as np
from sklearn.pipeline import FeatureUnion
from sklearn.preprocessing import MinMaxScaler

logger = logging.getLogger(__name__)
logging.basicConfig(level=logging.INFO)


class MyMinMaxScaler(MinMaxScaler):
def fit(self, X, y=None):
logger.info("fitting MyMinMaxScaler")
print("fitting MyMinMaxScaler")
super().fit(X, y)


fu = FeatureUnion(
[("myscaler", MyMinMaxScaler()),
("regular_scaler", MinMaxScaler())],
n_jobs=-1
)

data = np.array([40, 41, 42]).reshape(-1, 1)
fu.fit(data)
logger.info(fu.transform(data))


Output n_jobs=-1



fitting MyMinMaxScaler
INFO:__main__:[[0. ]
[0.5]
[1. ]]


Output n_jobs=1



INFO:__main__:fitting MyMinMaxScaler
fitting MyMinMaxScaler
INFO:__main__:[[0. ]
[0.5]
[1. ]]


I wonder if this is the intended behavior. I was thinking this may be related to multiprocessing and output from child processes not showing up. But why would regular print() statements work as usual and logging output would not?



This behavior, at first, let me believe that my transformers weren't actually being fitted and thus not used at all. It's obviously not a big deal now that I know that the transformers are being used as expected. I would, however, appreciate some insight into why this logging behavior may occur the way it does, and if there is any way around it.










share|improve this question















Using a FeatureUnion with some custom transformers I noticed that some output wasn't showing up in my terminal that I was expecting from logger.info() statements within the transformers. After digging around, I was able to track it down to the FeatureUnion's n_jobs parameter. If it is not set to n_jobs=1 output from loggers will not show up. However, output from regular print() statements does show up.



MWE



import logging
import numpy as np
from sklearn.pipeline import FeatureUnion
from sklearn.preprocessing import MinMaxScaler

logger = logging.getLogger(__name__)
logging.basicConfig(level=logging.INFO)


class MyMinMaxScaler(MinMaxScaler):
def fit(self, X, y=None):
logger.info("fitting MyMinMaxScaler")
print("fitting MyMinMaxScaler")
super().fit(X, y)


fu = FeatureUnion(
[("myscaler", MyMinMaxScaler()),
("regular_scaler", MinMaxScaler())],
n_jobs=-1
)

data = np.array([40, 41, 42]).reshape(-1, 1)
fu.fit(data)
logger.info(fu.transform(data))


Output n_jobs=-1



fitting MyMinMaxScaler
INFO:__main__:[[0. ]
[0.5]
[1. ]]


Output n_jobs=1



INFO:__main__:fitting MyMinMaxScaler
fitting MyMinMaxScaler
INFO:__main__:[[0. ]
[0.5]
[1. ]]


I wonder if this is the intended behavior. I was thinking this may be related to multiprocessing and output from child processes not showing up. But why would regular print() statements work as usual and logging output would not?



This behavior, at first, let me believe that my transformers weren't actually being fitted and thus not used at all. It's obviously not a big deal now that I know that the transformers are being used as expected. I would, however, appreciate some insight into why this logging behavior may occur the way it does, and if there is any way around it.







python logging scikit-learn






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share|improve this question













share|improve this question




share|improve this question








edited Dec 11 '18 at 18:19







pmlk

















asked Nov 23 '18 at 22:51









pmlkpmlk

10917




10917












  • How are you executing this? From an IDE or in terminal? If from an IDE, you will not get the output. If that ide is in turn started through terminal, then you will get the output on that actual terminal, instead of output space of IDE.
    – Vivek Kumar
    Nov 26 '18 at 14:43










  • I execute this in a terminal. I use and IDE only as a code editor.
    – pmlk
    Nov 26 '18 at 17:14










  • Can't reproduce - I see the log output you're not seeing with n_jobs=-1. CPython 3.6.3, scikit-learn 0.19.0.
    – user2357112
    Dec 11 '18 at 18:23










  • Can reproduce on scikit-learn 0.20.1. Something must have changed between those versions.
    – user2357112
    Dec 11 '18 at 18:24










  • print(logger) shows that the logger's level is WARNING instead of INFO inside fit.
    – user2357112
    Dec 11 '18 at 18:29


















  • How are you executing this? From an IDE or in terminal? If from an IDE, you will not get the output. If that ide is in turn started through terminal, then you will get the output on that actual terminal, instead of output space of IDE.
    – Vivek Kumar
    Nov 26 '18 at 14:43










  • I execute this in a terminal. I use and IDE only as a code editor.
    – pmlk
    Nov 26 '18 at 17:14










  • Can't reproduce - I see the log output you're not seeing with n_jobs=-1. CPython 3.6.3, scikit-learn 0.19.0.
    – user2357112
    Dec 11 '18 at 18:23










  • Can reproduce on scikit-learn 0.20.1. Something must have changed between those versions.
    – user2357112
    Dec 11 '18 at 18:24










  • print(logger) shows that the logger's level is WARNING instead of INFO inside fit.
    – user2357112
    Dec 11 '18 at 18:29
















How are you executing this? From an IDE or in terminal? If from an IDE, you will not get the output. If that ide is in turn started through terminal, then you will get the output on that actual terminal, instead of output space of IDE.
– Vivek Kumar
Nov 26 '18 at 14:43




How are you executing this? From an IDE or in terminal? If from an IDE, you will not get the output. If that ide is in turn started through terminal, then you will get the output on that actual terminal, instead of output space of IDE.
– Vivek Kumar
Nov 26 '18 at 14:43












I execute this in a terminal. I use and IDE only as a code editor.
– pmlk
Nov 26 '18 at 17:14




I execute this in a terminal. I use and IDE only as a code editor.
– pmlk
Nov 26 '18 at 17:14












Can't reproduce - I see the log output you're not seeing with n_jobs=-1. CPython 3.6.3, scikit-learn 0.19.0.
– user2357112
Dec 11 '18 at 18:23




Can't reproduce - I see the log output you're not seeing with n_jobs=-1. CPython 3.6.3, scikit-learn 0.19.0.
– user2357112
Dec 11 '18 at 18:23












Can reproduce on scikit-learn 0.20.1. Something must have changed between those versions.
– user2357112
Dec 11 '18 at 18:24




Can reproduce on scikit-learn 0.20.1. Something must have changed between those versions.
– user2357112
Dec 11 '18 at 18:24












print(logger) shows that the logger's level is WARNING instead of INFO inside fit.
– user2357112
Dec 11 '18 at 18:29




print(logger) shows that the logger's level is WARNING instead of INFO inside fit.
– user2357112
Dec 11 '18 at 18:29












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