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I have downloaded and installed the CPLEX Studio Community Edition 20.1.0.0 on my Linux machine (KUbuntu). I want to use the oplrun tool directly from the terminal. I can run it just fine. However, at the start of the program, it displays a message that says:

IBM ILOG CPLEX Optimization Studio Community Edition.  The CPLEX Optimizers will solve problems up to 1000 variables and 1000 constraints.
Problem size limit exceeded.
CP Optimizer Community Edition solves problems with search spaces up to 2^1000.
Unrestricted version options (including academia) at https://ibm.co/2s0wqSa

The message appears whatever input I use, and then, weirdly enough, it proceeds to solve the problem. I've tested with many different OPL examples at <install-dir>/opl/examples/opl. The above message in particular appeared when I used the input files at <install-dir>/opl/examples/opl/knapsack, which is a small example with just a few variables. So I have two questions:

  1. Why does this message appear?
  2. Why it proceeds to solve the problem if the problem is "supposedly" too large? Is the solution returned valid?
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Indeed even for models that are small enough like knapsack you get the message

IBM ILOG CPLEX Optimization Studio Community Edition. The CPLEX Optimizers will solve problems up to 1000 variables and 1000 constraints. Problem size limit exceeded. CP Optimizer Community Edition solves problems with search spaces up to 2^1000. Unrestricted version options (including academia) at https://ibm.co/2s0wqSa

but you should not see

Problem size limit exceeded.

That's a bug. But it is normal to be able to solve this with the FREE CPLEX community edition.

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