Learn with Phoebe ยท Data Science

Learn Prescriptive Analytics with Phoebe

Ravensworth Mills makes three feeds. Show earns 71 a tonne, nearly double Standard at 38, so the obvious move is to make more Show. The optimal plan makes none of it at all, because Show eats 2.3 milling hours a tonne against Standard's 1.1, and the mill is not allocating margin, it is allocating hours. That is the whole subject in one result: prediction tells you what will happen, and something else entirely tells you what to do about it. Six leader sessions on reading and challenging a plan, ten practitioner sessions building the solver that produces one, and every figure here computed by a real simplex implementation running in the page.

16sessions, two tracks
1,100problems cross-checked against brute force
2faults that check found
60the cost of rounding the answer
45min per session

Leader track ๐Ÿงญ ยท six sessions, no code

For anyone handed a plan and asked to approve it. Why the obvious allocation is usually wrong, what a constraint is actually worth and for how long, what "optimal" quietly assumed, and the five questions to ask about a plan you did not produce.

Practitioner track ๐Ÿ—๏ธ ยท ten sessions, hands on

For the people who build the model. Writing the problem down, the feasible region, simplex, shadow prices and their range, integers, formulation traps, Monte Carlo, robust planning, a solver that was wrong twice, and a capstone bench.

Foundations Working depth Advanced Hardest

The whole thing on one page

Every idea in the course and the session that owns it. Click any node to jump there.

Three ways through

Everyone starts at session 1 of their track. These are the shortest useful routes if you cannot take all sixteen.

Somebody hands me a plan Allocation, not rankingโ†’ Optimal for whatโ†’ Five questions
Someone wants to buy capacity What it is worthโ†’ And for how longโ†’ Under uncertainty
I build the model Write it downโ†’ Simplexโ†’ Integersโ†’ The bench

What is real here

The solver is a simplex implementation written from the method, with branch and bound over its relaxation. Every plan on every page is computed, not stored.

The solverCarries three problems whose optima can be checked by hand, and runs them on load
And it was wrongPassing those three was not enough. A cross-check over 1,100 generated problems found two faults in opposite directions, one in the solver and one in the checker
Every shadow priceQuoted with the range it holds over, because 33.79 an hour stops being true after 0.46 of an hour
Every planRun against drawn demand as well as average demand, because those give different answers