gcc crashes compiling output about m2cgen

[izeigerman]

Hey @beojan, thanks for reporting this issue! Can you please provide a bit more info on what algorithm caused that with what set of hyperparameters so that we can attempt to reproduce it locally.

UPD: The error with which gcc fails will be helpful too!

[beojan]

I'm using an XGBClassifier with max_depth=10, n_estimators=500, learning_rate=0.2, max_delta_step=15.

There are 5 floating point features.

[izeigerman]

@beojan I've attempted to reproduce the issue in the following way:

1. I trained an XGBoost Classifier using the Breast Cancer dataset from scikit-learn (30 floating point features) and hyper parameters that you've provided:

>>> from sklearn import datasets
>>> import xgboost
>>> dataset = datasets.load_breast_cancer()
>>> X, y = dataset.data, dataset.target
>>> model = xgboost.XGBClassifier(max_depth=10, n_estimators=500, learning_rate=0.2, max_delta_step=15)
>>> model.fit(X, y)
XGBClassifier(base_score=0.5, booster='gbtree', colsample_bylevel=1,
       colsample_bytree=1, gamma=0, learning_rate=0.2, max_delta_step=15,
       max_depth=10, min_child_weight=1, missing=None, n_estimators=500,
       n_jobs=1, nthread=None, objective='binary:logistic', random_state=0,
       reg_alpha=0, reg_lambda=1, scale_pos_weight=1, seed=None,
       silent=True, subsample=1)

2. I generated C code using m2cgen and stored it on a file system:

>>> import sys
>>> import m2cgen as m2c
>>> sys.setrecursionlimit(5000)
>>> code = m2c.export_to_c(model)

3. I compiled the generated source using gcc of the following version:

sauser@iaroslav-vm:~$ gcc --version
gcc (Ubuntu 4.8.4-2ubuntu1~14.04.4) 4.8.4

And it worked just fine:

sauser@iaroslav-vm:~$ gcc -c -o xgboost.o xgboost.c && echo $?
0

4. I also tested the same source with clang on Mac and it worked after I increased the bracket-depth:

$ gcc -c -o xgboost.o xgboost.c
xgboost.c:2977:291: fatal error: bracket nesting level exceeded maximum of 256
xgboost.c:2977:291: note: use -fbracket-depth=N to increase maximum nesting level
1 error generated.

$ gcc -fbracket-depth=1024 -c -o xgboost.o xgboost.c

@beojan As you may see - so far I couldn't reproduce the issue. Can you please share the version of gcc using which issue reproduced? Can you please try the xgboost.c source that I generated (in attachments) to see whether it compiles with your gcc?
xgboost.c.txt

UPD knowing the number of classes in your target would also help since in a multi-class scenario XGBoost creates N (500 in your example) estimators per class which may lead to a pretty large source code output.

[izeigerman]

Closing this issue due to lack of activity and inability to reproduce it. Please feel free to reopen if necessary.