[Feature Request] Allow multirun default through config

[jan-matthis]

🚀 Feature Request

Motivation / Pitch

I mostly use hydra to sweep over configs, requiring -m / --multirun. It would be great if it was possibly to default to multirun through Hyrda's configuration.

Additional context

Following discussion with @omry on Zulip.

[omry]

Thanks, this is a nice idea. I will try to get it for 1.1.0 (next major version).

[omry]

the motivation to make -m the default is to use the configured launcher, right? (without sweeping).

[jan-matthis]

No, it's actually mostly to get sweeping per default

[omry]

I am going to bounce it to 1.2, there will probably be a more serious restructuring there that can address this as well.

[jieru-hu]

cc @jgbos
I think this particular change would make it easier for your PL + Hydra DDP work (planned for 1.2, which we are hoping to release in a couple of months)

[jieru-hu]

@jan-matthis this is available now on the Hydra main branch. Feel free to check it out and let us know your thoughts/feedback if you can :) thanks!

(we will also release a dev version soon )