How can I use linear programming to distribute S into two bins?

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Discussion Overview

The discussion revolves around using linear programming to solve a problem of distributing a total amount, denoted as S, into two bins, with one bin further divided into smaller bins. Participants explore how to maintain a specific ratio between the two bins and achieve an even distribution among the smaller bins within the first larger bin.

Discussion Character

  • Exploratory
  • Technical explanation
  • Mathematical reasoning

Main Points Raised

  • One participant describes the problem of distributing S into two bins, S_a and S_b, with S_a containing smaller sub-groups and aims to maintain a specific ratio of items between S_a and S_b.
  • Another participant questions the definition of S_b, suggesting it may be self-referential.
  • A participant provides a clearer example to illustrate the problem, explaining the need to keep the ratio of items between S_a and S_b while also ensuring an even distribution among the smaller groups G_i within S_a.
  • The example includes constraints such as the maximum number of items that can fit in each sub-group and the total budget constraints.

Areas of Agreement / Disagreement

Participants do not appear to reach a consensus on the clarity of the problem statement, with some expressing confusion over the definitions and equations provided. Multiple interpretations of the problem exist, indicating that the discussion remains unresolved.

Contextual Notes

Participants note the importance of defining variables clearly and establishing constraints for the distribution problem. There are indications of missing assumptions and the need for further clarification on the mathematical formulation.

timeone
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I have a problem at work I'm trying to solve and I can't figure out a good way to do it, hoping someone might be able to help. I have put the relevant info in the below pastebin. Basically I want to distribute some amount of S into two bins, one of which is split into smaller bins, in such a way that the amount between the two is as close to some give ratio as it can be, and then the amount in the first larger bin is split as close as equally among the smaller bins inside of it.

I was thinking about the Simplex algorithm but not sure how well it would work...

http://pastebin.com/wsR86rev
 
Last edited by a moderator:
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Sorry, I'm confused; seems you're defining ## S_b## in terms of itself?
 
timeone said:
I have a problem at work I'm trying to solve and I can't figure out a good way to do it, hoping someone might be able to help. I have put the relevant info in the below pastebin. Basically I want to distribute some amount of S into two bins, one of which is split into smaller bins, in such a way that the amount between the two is as close to some give ratio as it can be, and then the amount in the first larger bin is split as close as equally among the smaller bins inside of it.

I was thinking about the Simplex algorithm but not sure how well it would work...

http://pastebin.com/wsR86rev

From Pastebin at the link above:
1.S_a = c_1 * I_1 + c_2 * I_2 + ... + c_n * I_n
2.S_b = c_Sb * I_Sb
3.S_total = S_a + S_b
4.0 <= I_i <= k_i
5.0.00 <= r <= 1.00
6.I_i is a positive integer for all i in {1..n}
7.sum(I_i for all i in {1..n})/I_Sb <= r/(1-r)

9.find all I_i, I_Sb

10.minimize |I_j - I_k| for all j,k in {1..n} and j != k and j,k != Sb (basically want as much of an even split as possible in S_a)

12.known constants: c_i, r, S_total, k_i

13.|x| is absolute value of x
This is gibberish until you tell us more clearly what you're trying to do.
 
Last edited by a moderator:
Hi Mark,
Sorry for being too vague, I was trying to reduce it into a series of equations to make the linear algebra problem more clear. I'll give an example:

Suppose ## S## is the total budget say $100, ## S## should be split into two sub groups, ## S_a## and ## S_b##. ## S_a## contains sub groups, ## G_1## through ## G_n##, and ## G_i## = ## c_i##*## I_i##. Think of ## c_i## as some fixed cost per item for a group of items ## I_i##. The second top level group, ## S_b##, is the spillover group. Give some percentage, say r=30%, I'd ideally like 30% of the items in group ## S_a## and 70% in group ## S_b##. This doesn't necessarily mean the budget is split 30/70, just the items. Only so many items can fit in each sub-group( ## I_i## <= ## k_i## ). If not all the items can fit in ## S_a## , put them in the ## S_b## along with the other 70%.

Basically I'm trying to figure out how many items can go in each group, keeping the ratio of items between ## S_a## and ## S_b##, keeping an even split of items between all sub-groups ## G_i##, and having the sum of all groups equal the total budget.
 

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