FSRS Helper "Reschedule All Cards" reduces load balance stability

[ratman-codes]

See above for a deck with a large amount of historical reviews. According to stats I have an 89.3% total retention in the past year. When I press reoptimize, it says that I have optimal FSRS weights and has said that for the past few months (I do reop once a month).

In the past, when I would reschedule all cards with FSRS Helper, it would usually slightly adjust my daily rate of cards and also improve load balancing. In this case my average is around 89% so I'd expect my daily rate to increase a little most likely. However, today I optimized (no change) then rescheduled all and got this result:

Ignoring day 0 which is just strangeness in how some due dates got rescheduled to the past. My day 1 and beyond load balancing is in my opinion poor. There are some peaks and valleys that I never would have seen in the past, and even compared to my current deck state this is a downgrade in terms of load balance.

I don't think FSRS Helper had this issue before. Could this be related to some changes in FSRS algorithm recently? I am undoing this reshuffle for now because I'm not confident in the algorithm being used right now for reshuffling.

[L-M-Sherlock]

Due to #520, the workload scheduled by the new load balancer is not as smooth as the previous one. In #520, the Helper's load balancer is consistent with Anki's built-in load balancer, which introduced more randomness and tend to alleviate the impact on retention.

[ratman-codes]

Thank you. OK, so just to be clear this is working as intended? If so that's all good, I can stomach the worse load balancing if it means better retention rates.

[L-M-Sherlock]

Yes, it's intended, especially when your daily workload is less than 100.

[JSchoreels]

@ratman-codes with recent #624 it could also have an impact, if you disabled the LB, because now there won't be smoothing unless you enabled the LB. But there are also other PR that could also impact that #626

[ratman-codes]

thanks for the info. I actually don't see where I can turn on Load balancing anymore in anki or fsrs helper.

[JSchoreels]

Open the debug console of Anki : https://docs.ankiweb.net/misc.html#debug-console

Then :

# Enable LB
mw.col._set_load_balancer_enabled(True)
# Disable LB
mw.col._set_load_balancer_enabled(False)
# See status
print(mw.col._get_load_balancer_enabled())

[ratman-codes]

oh got it, thank you for sharing. I'm assuming this isn't meant to be turned on if it has to be done via console, dont want to screw something up.