Community Digest

Top new questions this week:

Where can I find documentation on good practices for efficient formulations of a problem?

I am sort of new to mathematical optimization and have to build some fairly complicated models for my thesis. I was wondering where I could find literature to help me develop more efficient versions ...

mixed-integer-programming modeling reference-request  
asked by J. Dionisio 12 votes
answered by Kuifje 12 votes

How to prove pseudo-convexity of a discrete function?

Given a general function $f:\Bbb Z\to\Bbb R$ is there a simple way to verify whether $f(x)$ is pseudo-convex or not?

combinatorial-optimization convex-optimization optimality-conditions  
asked by Lici 4 votes
answered by Nikos Kazazakis 2 votes

Control & Experimental Group Selection Methodology using STDEV and T-Test?

I would like to know if my methodology was 'correct': I am trying to conduct an experiment on my stores. I would like to find out the effect of a marketing campaign on the number of transactions. Only ...

optimization modeling python  
asked by tom pelletier 3 votes
answered by prubin 1 vote

Model if-else statement

I need to build a if-else constraint for this statement, where $x_P$ and $x_I$ are decision variables, and $C$ is a constant: if $x_P \ge C$ then $x_I = x_P - C$ else $x_I = 0$. Any help is greatly ...

optimization modeling  
asked by or230 3 votes
answered by RobPratt 5 votes

How to find range of values for the first-stage decisions resulting in the same cuts in two-stage stochastic programming?

Suppose we have a two-stage stochastic program as follows: \begin{equation} \begin{split} \min \ & c^Tx + \mathbb{E}_\xi[Q(x,\xi)] \\ & \text{where}\\ &Q(x,\xi)=\min q(\xi)^Ty\\ &Tx+...

stochastic-programming  
asked by Katatonia 3 votes

warmstarting simplex algorithm- how much can problems differ from each other?

I'm working on an implementation of the simplex algorithm. I want to solve problems in real time every 30 minutes. They could be interpreted as a classic transportation problem. I couldn't really say ...

optimization linear-programming python simplex dual-simplex  
asked by ORpyhton 2 votes
answered by prubin 0 votes

Is the Dynamic programming in Operations Research book the same dynamic programming in software industry?

Mostly when I search dynamic programming in google I get : dynamic programming (DP) in python, in C++, in java from web pages like geekforgeeks, litecode, codechef, and so on. But in the operation ...

python dynamic-programming  
asked by Locker05 2 votes

Greatest hits from previous weeks:

Solving a knapsack problem with a lot of items

I am wondering what are the fastest ways(faster than classical dynamic programming) to solve the knapsack problem (to optimality) with $n$ items when $n$ is nearly equal to $10000$ ? Apart from ...

dynamic-programming knapsack  
asked by Joffrey L. 17 votes
answered by Ruslan Sadykov 18 votes

Linear Programming with additional "if-then"/"Default to zero" constraints?

What approaches can I use for a Linear Programming problem with the additional constraint that if a decision variable falls below a certain threshold, then it should just be forced to 0. I'm ...

linear-programming convexity  
asked by Skander H. 17 votes
answered by David Bernal 9 votes

Shortest path problem with boxes

A company sells seven types of boxes, ranging in volume from 17 to 33 cubic feet. The demand and size of each box is given in the following table. The variable cost (in dollars) of producing each box ...

optimization  
asked by The Poor Jew 4 votes
answered by EhsanK 6 votes

Does adding constraint to an optimization model make it solve faster?

Some say adding constraints cuts the feasible region smaller hence the same solver terminates faster due to the less search effort. Others say it adds more complexity to the problem and it may take ...

optimization modeling  
asked by Mahmoud 3 votes
answered by LarrySnyder610 9 votes

What is the purpose of libraries like Pyomo and Google OR tools?

I'm new to the OR world, and trying to learn the various tools available. I originally thought that Pyomo and Google OR tools were open source alternatives to commercial solvers like Gurobi or CPLEX. ...

cplex pyomo gurobi modeling-languages  
asked by Skander H. 18 votes
answered by Bethany Nicholson 16 votes

How to linearize min function as a constraint?

I'm trying to solve an optimization problem including following constraint, and I need to linearize it in a maximization nonlinear programming model. Please help me to reformulate it with mixed ...

mixed-integer-programming optimization linearization logical-constraints  
asked by Vida 6 votes
answered by LarrySnyder610 8 votes

MATLAB vs. Python in industry

I am a beginning PhD student in math, and I would like to focus on optimization. I am learning programming for the first time, and I have written out some rudimentary optimization algorithms in both ...

optimization python matlab industry  
asked by Blue 29 votes
answered by Nikos Kazazakis 48 votes

Can you answer this question?

Gurobi c++: Getting constraint matrix

I'm trying to get the constraint matrix from a Gurobi model in C++. In Python, one can get this by simply calling a method that will populate a scipy object (see this post). However, in a C++ fashion, ...

solver gurobi c++  
asked by gdragotto 2 votes
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