[BUG] Attempting to save a model without specifying a path throws an exception on Windows

[JLC827]

Describe the bug
The model documentation states that when calling model.save the path parameter is optional, and that "If no path is specified, the model is automatically saved under "{ModelClass}_{YYYY-mm-dd_HH:MM:SS}.pt". E.g., "RNNModel_2020-01-01_12:00:00.pt".

However, if it is left unfilled the following exception will be thrown:

File "...\venv\lib\site-packages\darts\models\forecasting\torch_forecasting_model.py", line 1271, in save
    with open(path, "wb") as f_out:
OSError: [Errno 22] Invalid argument: 'RNNModel_2023-02-11_23:31:42.pt'

I assume this is because ':' cannot be used in file names in Windows. One possibility is to use the formatting of '%Y%m%d-%H%M%S' as specified in this Stack Overflow post.

To Reproduce
Simply run.

from darts.models import RNNModel

model = RNNModel(input_chunk_length=4)
model.save()

Expected behavior
It is expected for the model to save in the current working dir in a reasonable model name and date format.

System (please complete the following information):

• Python version: 3.10
• darts version 0.23.1
• Windows 10.0.19045

Thanks!

[madtoinou]

Hi,

I added a fix in PR #1501 (":" was replaced with "_"), it should be part of next darts release.

[JLC827]

Excellent, thank you @madtoinou!