MLPRegressor.partial_fit produces an error when early_stopping is True #25693
Description
Describe the bug
WIth sklearn = 1.2.1, when using early_stopping = True, fit works fine, but partial fit produces the following error:
I think this is related to this change: #24683.
Steps/Code to Reproduce
import numpy.random
from sklearn.neural_network import MLPRegressor
if __name__ == '__main__':
x = numpy.random.normal(size=(200, 4))
y = x[:, 0] * 2 + x[:, 1] * 3 + x[:, 3] + numpy.random.normal(size=(200,))
algo = MLPRegressor(early_stopping=True).fit(x, y)
algo.partial_fit(x, y)
Expected Results
If early stopping is not supported for partial fit, it should handle this gracefully. If this is a bug - it should be fixed.
Actual Results
Traceback (most recent call last):
File "/Users/ilyastolyarov/Repos/new/clpu/examples/usecases/script.py", line 12, in <module>
algo.partial_fit(x, y)
File "/Users/ilyastolyarov/Repos/new/clpu/.venv/lib/python3.8/site-packages/sklearn/neural_network/_multilayer_perceptron.py", line 1640, in partial_fit
return self._fit(X, y, incremental=True)
File "/Users/ilyastolyarov/Repos/new/clpu/.venv/lib/python3.8/site-packages/sklearn/neural_network/_multilayer_perceptron.py", line 471, in _fit
self._fit_stochastic(
File "/Users/ilyastolyarov/Repos/new/clpu/.venv/lib/python3.8/site-packages/sklearn/neural_network/_multilayer_perceptron.py", line 653, in _fit_stochastic
self._update_no_improvement_count(early_stopping, X_val, y_val)
File "/Users/ilyastolyarov/Repos/new/clpu/.venv/lib/python3.8/site-packages/sklearn/neural_network/_multilayer_perceptron.py", line 721, in _update_no_improvement_count
if self.loss_curve_[-1] > self.best_loss_ - self.tol:
TypeError: unsupported operand type(s) for -: 'NoneType' and 'float'
Versions
System:
python: 3.8.12 (default, May 16 2022, 17:58:21) [Clang 13.0.0 (clang-1300.0.29.30)]
executable: /Users/ilyastolyarov/Repos/new/clpu/.venv/bin/python
machine: macOS-11.6-x86_64-i386-64bit
Python dependencies:
sklearn: 1.2.1
pip: 22.3.1
setuptools: 64.0.2
numpy: 1.23.5
scipy: 1.9.3
Cython: 0.29.33
pandas: 1.5.3
matplotlib: 3.7.0
joblib: 1.2.0
threadpoolctl: 3.1.0
Built with OpenMP: True
threadpoolctl info:
user_api: blas
internal_api: openblas
prefix: libopenblas
filepath: /Users/ilyastolyarov/Repos/new/clpu/.venv/lib/python3.8/site-packages/numpy/.dylibs/libopenblas64_.0.dylib
version: 0.3.20
threading_layer: pthreads
architecture: Nehalem
num_threads: 8
user_api: openmp
internal_api: openmp
prefix: libomp
filepath: /Users/ilyastolyarov/Repos/new/clpu/.venv/lib/python3.8/site-packages/sklearn/.dylibs/libomp.dylib
version: None
num_threads: 8
user_api: blas
internal_api: openblas
prefix: libopenblas
filepath: /Users/ilyastolyarov/Repos/new/clpu/.venv/lib/python3.8/site-packages/scipy/.dylibs/libopenblas.0.dylib
version: 0.3.18
threading_layer: pthreads
architecture: Nehalem
num_threads: 8