Keeping Score

[From Bruce Abbott (941111.2100 EST)]

Bill Powers (941111.0530 MST)

Bill states:

The cases we do NOT see are if dNut > 0 then INCREASE the probability of
a tumble, and if it is < 0 then DECREASE the probability of a tumble.
That is what makes it work. Regardless of the state of NutSave, the
correct relationship between dNut and the change of probability of a
tumble remains correct, although because of using NutSave, half of the
time the wrong probability is changed. That gets corrected the next time
dNut changes sign. The wrong probability, however, is never changed in
the wrong direction for the sign of dNut. Whichever probability you are
using, it should decrease while dNut is positive, and that does happen.
So Ecoli4 eventually gets to the goal, if you wait long enough.

Enough of theses verbal arguments! Correct your copy of ECOLI4 to eliminate
the dNut carryover from pre- to post-tumble time by removing the leaky
integrater, thus leaving:

dNut := (NewNut - NutCon);

Increase the constant ENDSESSION to 50000, or some other big number so you
have plenty of time to watch.

Run ECOLI4 as often, for as long as you like. E. coli will occasionally find
the goal, and sometimes it will stay there a long time, but it will not
consistently go there and it will not consistently stay there when it does.
If it does, I'll buy you a steak dinner. If it doesn't, you buy me one.
Deal?

As to ECOLI2, I'll admit to misunderstanding your statement:

if Speed > 0.3 then Speed := Speed - LearnRate;
implements a little control system which maintains
speed at or less than 0.3.

As the two limits were intended to keep Speed BETWEEN 0.3 and 2.0 (with Speed
being driven up or down by the consequences of moving), it did not compute
with me when you said the system was trying to keep Speed below 0.3 or above
2.0. So I loose this one. Score: Bill 1, Bruce 1 (?)

On more important matters, I've completed my research protocol for the animal
care and use committee on the operant schedules project, and expect to have
approval to order rats in about a month or so. I've also been playing with
Operant3. I'll have some comments when I've had a bit more time to explore
its behavior under various parameters. Regarding the learning model of e.
coli, I've had some thoughts of my own concerning how to handle this; when I
get some "play" time I'll try to model both approaches and see which works
best.

Regards,

Bruce (;->