Question about update coord in JokeRec/step in rayrllib/recsys/01-Recsys.ipynb

[jamesliu]

centers dimension is like [clusters, users], c dimension will become [users], why do we get c[item]?
For example, if we have cluster =7, users=2000, items=101, shouldn't we get c[user] instead of c[item]?

class JokeRec (gym.Env):
def step(self):
...
# update the coords history: agent observes its distance to each cluster "evolve"
for i in range(len(self.coords)):
c = self.centers[i]
scaled_diff = abs(c[item] - rating) / 2.0
self.coords[i] += scaled_diff ** 2.0