maximizing sum over feasible set of vectors

asked 5 years ago

anonymous user

Anonymous

updated 5 years ago

Let [5] be the set of the first 5 positive integers. We let α_=(αA)A,A[5] consist of a vector with 31 real entries, where each αA is associated with a subset A[5].

Define OBJ(α_)=A[5],AαAlog(|A|), v(α_)=A[5],AαA, and E(α_)=A,B:ABαAαB, where the sum for E(α_) is taken over all unordered pairs of disjoint nonempty sets A and B, where A,B[5].

Also define FEAS(1/4) to be the set of all such vectors α_ with nonnegative real entries such that v(α_)=1 and E(α_)1/4.

I want to learn how to program the following optimization problem: OPT(1/4):=maxα_FEAS(1/4)OBJ(α_)

I was told that I can do this in SageMath. I have some basic knowledge of how to use Sage. How could I create the set FEAS(1/4)? I think that from there I may be able to figure out how to maximize OBJ(α_) over this set.

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Comments

Homework ?

Emmanuel Charpentier gravatar imageEmmanuel Charpentier ( 5 years ago )

Also, go easy on (pseudo-)formalism: I can't make head or tails of your definition of α_... For another example, you define A as a subset of [5] ; but now, what is log(|A|) ???

Emmanuel Charpentier gravatar imageEmmanuel Charpentier ( 5 years ago )
1

|A| means the number of elements in A. To have α_ be a vector one should choose an ordering of the (nonempty) subsets of [5], e.g. by identifying them with binary strings of length 5 (not equal to 00000).

rburing gravatar imagerburing ( 5 years ago )
1

Okay. you want to (pedantly) number the components of α_ in binary. And to ignore α0. Right ?

A is therefore an index of the 31 components of α_,v(α_) is 32i=1αi1. Still right ?

Emmanuel Charpentier gravatar imageEmmanuel Charpentier ( 5 years ago )

I didn't ask the question, but yes that's right. The binary ordering was just a (natural) suggestion. Of course the ordering is irrelevant, but probably some ordering is necessary for the implementation.

rburing gravatar imagerburing ( 5 years ago )