Thank you Christian. That thread with the updated API yields the following code, which will fix the shaker volume variables so they do not update:
import theano.tensor as tt
rand_stream = tt.random.utils.RandomStream()
with pm.Model() as model:
yeast_conc = pm.Normal("yeast conc",
mu=2 * billion, sd=0.4 * billion)
shaker1_vol = pm.Deterministic("shaker1 vol",
rand_stream.normal(9.0, 0.05))
shaker2_vol = pm.Deterministic("shaker2 vol",
rand_stream.normal(9.0, 0.05))
shaker3_vol = pm.Deterministic("shaker3 vol",
rand_stream.normal(9.0, 0.05))
I added similar code to an example in the notebook link (previous post) in case others need to solve the same problem.
Thanks,
Greg