Hi all,
Using the same X and y values sklearn.linear_model.LogisticRegression.fit() is
providing me with inconsistent results.
The documentation for sklearn.linear_model.LogisticRegression states that "It
is thus not uncommon, to have slightly different results for the same input
data.” I am experiencing this, however the fix of using a smaller “tol”
parameter isn’t providing me with consistent fit.
The code I’m using:
def log_run(logreg_x, logreg_y):
logreg_x['pass_fail'] = logreg_y
df_train, df_test = train_test_split(logreg_x, random_state=0)
y_train = df_train.pass_fail.as_matrix()
y_test = df_test.pass_fail.as_matrix()
del(df_train['pass_fail'])
del(df_test['pass_fail'])
log_reg_fit =
LogisticRegression(class_weight='balanced',tol=0.000000001).fit(df_train,
y_train)
predicted = log_reg_fit.predict(df_test)
accuracy = accuracy_score(y_test, predicted)
kappa = cohen_kappa_score(y_test, predicted)
return [kappa, accuracy]
I’ve gone out of my way to be sure the test and train data is the same for each
run, so I don’t think there should be random shuffling going on.
Example output:
---
log_run(df_save, y)
Out[32]: [0.027777777777777728, 0.53333333333333333]
log_run(df_save, y)
Out[33]: [0.027777777777777728, 0.53333333333333333]
log_run(df_save, y)
Out[34]: [0.11347517730496456, 0.58333333333333337]
log_run(df_save, y)
Out[35]: [0.042553191489361743, 0.55000000000000004]
log_run(df_save, y)
Out[36]: [-0.07407407407407407, 0.51666666666666672]
log_run(df_save, y)
Out[37]: [0.042553191489361743, 0.55000000000000004]
A little information on the problem DataFrame:
---
len(df_save)
Out[40]: 240
len(df_save.columns)
Out[41]: 18
If I omit this particular column the Kappa no longer fluctuates:
df_save[‘abc'].head()
Out[42]:
0 0.026316
1 0.333333
2 0.015152
3 0.010526
4 0.125000
Name: abc, dtype: float64
Does anyone have ideas on how I can figure this out? Is there some
randomness/shuffling still going on I missed?
Thanks!
Chris
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