# All Questions

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### Solving pricing problem heuristically in column generation algorithm for VRP

In the set covering/column generation approach for the VRP (Balinski and Quandt (1964), or e.g. this tutorial), the basic idea is: Generate some routes. Solve the set covering problem using those ...
199 views

### How does a warm start work in LP/MIP?

Can someone explain how warm starts/ MIP starts work? How do solvers like CPLEX/GUROBI use warm start with the Simplex algorithm? I am interested in understanding how the entire warm start ...
624 views

### Good textbook for queueing theory and performance modeling

Can someone recommend a good self-study textbook for queueing theory and performance modeling? My interest is in applying this to understanding the behavior of some real-world server networks, ...
247 views

### Is there a way to proportionalize fixed costs in a MILP?

So assume we have a MILP (e.g. inventory or capacity planning) and the objective is to minimize total costs (inventory costs, set-up costs, backorder costs, production costs etc.). The production of a ...
221 views

### Stochastic VRP: Sources of uncertainty and modeling approaches

In one of the archived research topics of mine, I tried to model and solve SVRPs using Multiple Tandem Queues. I have two related questions: What are the sources for uncertainty in Stochastic VRPs? ...
633 views

### Modeling the uncertainty of the input parameters

There are many approaches to deal with the uncertainty such as stochastic programming, robust optimization and fuzzy programming. Finding a suitable approach that is applicable in the real situations ...
197 views

175 views

### Difference between Chance constraints and logical constraints

A logical constraint combines linear constraints using logical operators, such as logical-and, logical-or, negation (that is, not), conditional statements (that is, if ... then ...) to express complex ...
181 views

### Some theories and laws of Operations Research? [closed]

Can I know some theories and laws of Operation Research which has being widely used nowadays?
2k views

### Does the problem of P vs NP come under the category of Operational Research?

I am enrolled in an Operational Research program. I am also interested in Algorithms, and I wish to know whether "P vs NP" is a common point in both of the fields, so that the effort put in ...
130 views

### Can docplex (module for Constraint Programming optimizer CPLEX for Python) read .lp or .mps file?

I want to solve a problem with docplex.cp (module for Constraint Programming optimizer CPLEX for Python), and the problem is available in ...
394 views

### Estimation of the size of Branch-and-Bound trees using ML

A short background: A paper [1] published in 2006 intends to show that the time needed to solve mixed-integer programming problems by branch and bound can be roughly predicted early in the solution ...
117 views

### Are there examples of spatially explicit MIP problems?

Disclosure: I am an MSc student in economics, but not an expert by any means in OR. I am trying to model a spatial MIP problem of an invasive species similar to this academic paper, however, my ...
483 views

### Deploying OR solutions and shipping projects

My background is a bachelor in mathematics. I learned basics OR on my own using the following : Introduction to Operations Research by F. Hillier and G. Lieberman Integer programming by l. Wolsey How ...
2k views

### Applications of pure mathematics in operations research

This is a question that I've been thinking about for a while, as my background is mainly on pure mathematics. From a few OR papers that I've looked at, I could identify some areas of pure mathematics ...
112 views

### How to modify EMSR when capacity for each fare class is different

In the normal EMSRa and EMSRb (Expected Marginal Seat Revenue) algorithms, each fare class is utilizes exactly 1 unit of capacity (for example, one seat on a plane). But I have a similar problem for ...
5k views

### How to innovate in OR

I am a graduate student in OR and I want to build one or two independent projects that go beyond academic projects in my university. I would like to target average people and/or those in the industry ...
496 views

### Complexity of verifying optimality in (mixed) integer programming

I looked around for a while, but I couldn't find a precise answer to the following question. If I'm given a candidate solution for a (mixed) integer (convex) program, what's the complexity of ...
2k views

### A variant of the Multiple Traveling Salesman Problem

I am trying to find a reference (or a reformulation) of a variant of the multiple Traveling Salesman Problem, where multiple agents need to visit each vertex in a graph with minimal cost. Most of the ...
232 views

### How do you keep track of the latest publications in OR

It seems the most common answer to this question is: we periodically scan the websites of our favorite OR journals This approach however has several problems: you are likely to miss articles. you ...