Multiple default entries from the same folder

[ClementPinard]

Hi sorry for the potentially silly question, I just discovered the tool (which seems to be great !)

I have a process which uses two detections. The detection itself has a set of presets

config.yaml
detection
 ├── easy.yaml
 └── hard.yaml

detection/easy.yaml

box_threshold: 0.2

detection/hard.yaml

box_threshold: 0.5

If I only have one detection happening, I can have have the following config.yaml :

defaults:
- detection: easy
- _self_

But what if I want two detections in my process that could use a different set of defaults ? Would be possible to have something like

defaults:
- first_detection: detection/easy  # just a pseudo syntaxe to show what I want to do
- second_detection: detection/hard
- _self_

The idea would be to have a redirection so that first_detection does not look into "first_detection" folder but in "detection", same for "second_detection"

For now I managed to have the desired effect by simply having a first_detection and a second_detection folders, but since the configs share the exact same structure, I feel like it would be optimal to have everything in the same folder.

[odelalleau]

Yes, use something like

defaults:
- detection@first_detection: easy
- detection@second_detection: hard
- _self_

Relevant doc: https://hydra.cc/docs/advanced/overriding_packages/#using-a-config-group-more-than-once

[ClementPinard]

Perfect, thank you very much !

[ClementPinard]

Hey, I just applied the solution and it works great, except when overriding the group

When overriding config groups with a non-default package, the package must be used:
python my_app.py server/db@src=sqlite

I did not succeed in applying this method, but simply calling python my_script.py first_detection.box_threshold=0.5 seemed to work.

Is this the right behaviour ? According to the doc, I though it would be python my_script.py detection@first_detection.box_threshold=0.5 . Is the doc outdated ?

Anyway, I am glad the seemingly working command is much more readable 😄

[odelalleau]

The two syntaxes do very different things:

• python my_script.py first_detection.box_threshold=0.5 sets first_detection.box_threshold to the float value 0.5 (there is no config group involved here)
• python my_script.py detection@first_detection.box_threshold=0.5 looks into your detection config subfolder for a file named 0.5.yaml and copies its content into the first_detection.box_threshold node (though it probably won't work because (i) I don't think 0.5 is recognized by the grammar as a valid name for a config file, and (ii) I'm also not sure if you are allowed to set a config group on the command line unless you already have a default choice in the defaults list)