IBM Ponder This Challenge is a monthly puzzle IBM Research started in May 1998. Puzzles are not only games but also very useful at getting better at modeling business problems : turn human sentences into nice equations and solve them. The current IBM puzzle master is Oded Margalit

1- I was first at the IBM Research Ponder This Challenge September 2019 and what I used in order to be fast is IBM CPLEX with the OPL modeling language. Within CPLEX, one can use 2 solvers and I used the linear solver. I even relied for once on a very useful feature : solution pools. This is a way to ask CPLEX not one solution but several solutions.

2- I was second at the the IBM Research Ponder This Challenge May 2018 and what I used in order to be fast is IBM CPLEX with the OPL modeling language. Within CPLEX, one can use 2 solvers and I used the constraint programming solver (CPOptimizer). This solver is very good for scheduling but also for very combinatorial problems.

34- This is my rank in the IBM Research Ponder This TOP 41 solvers. Those puzzles gave me a lot of fun. They are very useful since in my day to day job I have to model business problems , turn them into OPL CPLEX and solve them.

So in a nutshell:

A) I do not know if solving those puzzles helped me get better in solving real business problems or if conversely tackling hard problems at customers was a good training for those IBM Research puzzles.

B) Optimization was described by Jean-François Puget as the best kept secret in IT. Many people know CPLEX but not enough people know that within CPLEX we do not only have the best linear solver but also CPOptimizer, the best constraint programming engine. Forgetting about the two engines is like trying to always use a hammer when you have both a hammer and a screwdriver!

hammer and screwdriver

C) Those 2 puzzles are finance puzzles. The first one is about central banks and the second one is about fraud detection. IBM CPLEX can help all industries save millions. In finance, millions can get billions!