Add R0 slider

[swo]

• User specifies one of R0 or infection rate to specify
• The other value is shown on a grayed-out slider
• On the backend:
  • The upper and lower limits for infection duration are set (with the duration > 0 as a requirement, to avoid infinite infection rate)
  • R0 has upper and lower limits (lower limit is zero)
  • Limits on infection rate are set by limits on duration and R0
• If infection rate is varied, and it is set so high that R0>10, then a warning displays

Resolves #37

[afmagee42]

I had to have the order of the two sliders swap. There's probably some way to do this nicer, but this is a start.

Probably something with either st.empty() or st.session_state. But agreed it's not a serious issue.

Limits on infection rate are set by limits on duration and R0. To get to the maximum value, duration and R0 must both be pulled to their maximum, which maybe is a little weird, but I think it's the only way to make it work.

That is not the experience I'm having running the app. The greyed out bar for infection rate gets a bigger maximum when I set R0 and infection duration to maximum. But then when I toggle to infection rate, it gets set to the default and its range goes to [0,1].

[afmagee42]

I think that if you want persistent behavior across changing the R toggle, you might need session_state?

[swo]

I think that if you want persistent behavior across changing the R toggle, you might need session_state?

Reworked! It took me a while to figure out how to do this, but it was simpler in the end than I expected

The thing I settled on was:

• Give each slider a key
• Set the default values for the sliders by adjusting the session state at the top of the script
• Set the slider values in callbacks using the session state
• Use the output values from the sliders in downstream logic (I think it would be equivalent to use the session state value, but this looks cleaner; the callback logic is in session state, and the downstream logic is all in normal variable)

[afmagee42]

If I mess with the infectious_duration slider at all now I get

AssertionError:
Traceback:
File "ringvax/app.py", line 359, in
app()
File "ringvax/app.py", line 155, in app
assert np.isclose(R0, infection_rate * infectious_duration)

This goes away if I then touch R or the infection rate. Which means... something

[afmagee42]

I have tried adding the R0 callback, alternately the rate callback, to infectious_duration and making sure infectious_duration had a session_default but the error persists.

Print-statement debugging says R0 isn't being recomputed in either case, so while I can't rule out that those are missing, I think the callbacks are not quite right?

[afmagee42]

#50 (comment)