Help trying to program a regression with random walk

Modeling
4

I just re-read what I wrote and feel like a bit of a goof.

Don’t say (what I originally wrote):

logalpha[i] ~ logalpha[i-1] + normal(0, sigmaw);

Say (what I corrected it to):

logalpha[i] ~ normal(logalpha[i-1], sigmaw);

I’m not sure what the first thing means, and it definitely isn’t valid code ~~.