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88 Topics

Errors with constraint programming

Hello,I am a beginner with aimms programmation. I added a constraint which is :sum[t,BackLog(i,t)|t>14]=0But when i compile my model, it gives me this message error: Constraint programming constraints cannot be used in combination with real valued variables, only with integer valued variables, el...

Supply Chain

Determine where the robot has to drive

Hello dear AIMMS Community, currently im working on a simulation of robots driving in a parking garage and charging electric vehicles.The first step is done and it is kind of working, but i have currently two major problems. even if i am not putting any demand on the parking lot the robots drive to...

Developers (Math, OR, programming)

Simplex task solved mathematically - how to program it in AIMMS?

Hello, I am a Master Student at the University of Applied Sciences. I found your website by chance, because you have knowledge in production management. Recently we started working in production management with the software AIMMS. However, I don't know how to transfer or programming the simplex-mode...

Developers (Math, OR, programming)

solveFixed using AIMMS

Dear Community; We are working with some MILP problems where we need to identify the ShadowPrice of some constraints. These constraints are made up of both binary and continuous variables. As the duality is not well defined for MILP problems, one method to find the ShadowPrice is to run a LP fixed m...

Developers (Math, OR, programming)

Very long execution time with BARON solver

Hello,I am solving small MINLP problem using BARON solver to find the ‘optimal’ solution. But for such a small system, 8 hours passed and I have not got the solution yet. My question is: why this solver cannot find the solution after such a long time? Is this because of the way I implemented the mod...

Developers (Math, OR, programming)

MIP Start with CPLEX

Hi, I would like to know how I can give an initial integer solution to a MIP solved with CPLEX. I found this link on the topic but I’m not convinced about the option it suggests for CPLEX in particular “Advanced basis” sounds like a setting to warm start an LP, not a MIP. I’m also not sure how to ac...

Developers (Math, OR, programming)

Article How OnLocation Analyzes the Impact of Renewables and Energy Storage on the U.S. Power Grid

OnLocation is an energy consulting company based in the Washington, D.C. area. They have extensive experience using integrated energy modeling to assess the costs and benefits of energy policies and technologies and provide insights into potential implementation challenges. OnLocation’s primary inte...

Developers (Math, OR, programming)

Article Using Machine Learning in AIMMS for better Decision Making

Why this articleIn this article, we will explain how Machine Learning and AIMMS can work together to complement the mathematical modeling and optimization capabilities of AIMMS as decision support technology. Why? Because we see an increasing need by our customers to understand its potential. Also,...

Developers (Math, OR, programming)

Next Analytics for a Better World is on October 28

1. The next Analytics for a Better World Webinar (ABW-W) is on Wednesday, October 28, 2020, EDT 12:00 PM (Boston time), CET 5:00 PM (Amsterdam time). Speaker: Jean-Philippe Vial (Geneva, Switzerland)Title: Analytics for the Design of Gravity-Driven Water Distribution Systems for Poor Rural Communiti...

Developers (Math, OR, programming)

Subset creation/formulation

Hello all,I am trying to create a subset of a main set for a constraint. See the attached figure of the constraint*. The index k should be a subset of its set. The main set consists for example of three classes {1,2,3}, then its subset should consist be{1,2}, so the main (ordered) set minus the last...

Developers (Math, OR, programming)

Memory ram manage

We have 2 aimms licenses, we would like to place them on the same server, is it possible to use one license for each project? Is it possible to manage ram memory used by the program being run by each license?

Developers (Math, OR, programming)

Article Analytics to the Rescue: Join AIMMS' N.S. Krishnan at INFORMS' Virtual Regional Conference

Join us this month at INFORMS' virtual regional conference! AIMMS' N.S. Krishnan (@nsk) will participate on the Panel Discussion "Analytics to the Rescue" on September 24, 12:25pm CST.About the conferenceThe conference will address the relevance of analytics to solve emerging issues, problems and ch...

Developers (Math, OR, programming)

How to delete all elements from a set prior to each execution

Hi,as the title indicates I’d like to delete all elements from a set prior to each execution. Otherwhise elements from the previous execution are messing up my results. Basically I have a set that will only contain elements under a certain condition, but if it doesn’t it still keeps the elements fro...

Developers (Math, OR, programming)

Article Suggested reading: Academic paper about Constraint Programming with AIMMS

Some of you may find this paper interesting - published 2013 but still relevant! “Developing Constraint Programming Applications with AIMMS” by Prof. Willem-Jan van Hoeve of Carnegie Mellon University Download the full paper in PDF from https://www.andrew.cmu.edu/user/vanhoeve/papers/aimms_cp_app.pd...

Developers (Math, OR, programming)

New initiative: Webinar for Analytics Practitioners

New initiative! Webinar for Analytics Practitioners (WAP) Back to School For Analytics practitioners it is difficult to remain up-to-date with respect to the newest scientific developments that are relevant for practice. There are at least two reasons why this is difficult for them: There...

Developers (Math, OR, programming)

How to define a set as empty under a certain condition

Hi,I think it would be helpful to provide a little bit of background regarding my problem first. I’m currently working on a project where a given set of volunteers should be assigned to a given set of people in need. So basically a simple transport problem, where the demand of all people in need is...

Developers (Math, OR, programming)

Minimize (max-min)

Hi, In my model I want to minimize the (maximum_t of a function) - (minimum_t of that function) and I have solved this issue by setting: k >= function for all tp <= function for all tand adding (k-p) to the objective of my model. When I do this for one variable, it works, but: when I do this t...

Developers (Math, OR, programming)

Having multiple solution with AOA

Hello,I am working with the MINLP problem which is solved by AOA in AIMMS. But I get different results whenever I run the code. Could you please tell me why this is happening? I can share my code with you if you need. Please tell me how to upload my code here?Regards

Developers (Math, OR, programming)

Setting initial point (solution) for CONOPT solver

Hello,I am solving a nonlinear problem in AIMMS using CONOPT solver and I need to set the initial solution. I have read the AIMMS language reference and also surf the internet for solving this issue. But according to AIMMS website only CPLEX, GUROBI and CBC support solving with an initial solution....

Developers (Math, OR, programming)

Bad scaling threshold default

Hello,I would like to know if there are any theorical references of why the default value of the bad scaling threshold is “1000”, or this default is due to the many yeras of experience of the Aimms developers?

Developers (Math, OR, programming)

specific constraints vehicle routing

Hello guys, currently im doing a Project at my University. I have to do a Simulation Pretty simular to the tutorial for begginers. But i have some more constraits which i have to imply but have no clue how to.code theese. In General: I have to get my products to the different customers. but i...

Developers (Math, OR, programming)

Modelling Question - if-then constraint

Dear all, I would really like to seek for your kind help regarding an if-then constraint. I found in the community a similar topic but my condition is a bit different from that, therefore I want to show my case and ask for your tips again. Specifically, I have the following variables: A: decis...

Developers (Math, OR, programming)

Robust optimization - applied project guidelines

Tutorial document (4 pages, 1 scheme, for download) Would you like to check how robust are your optimized decisions, if possible, construct better ones? Every project is different, with new people to be introduced to the idea, and it is handy to have a step-by-step guide on what to do to constru...

Developers (Math, OR, programming)

Multi Depot VRP with Intermediate Facilities

Hi teams, I’m working in multi-depot VRP with Intermediate Facilites and used assumptions as follow: vehicles will depart and return in same depot vehicles will only arrive at most one customer vehicles are heterogenous with two type of capacity But the model results infeasible integer solution,...

Supply Chain

Article Webinar (follow-up): Resilient Supply Chain Network Design

Q&A follow-up Many thanks to everyone who joined today's webinar Resilient Supply Chain Network Design presented by @Bhomik Jain, @Paul and @Aanand. We didn't have enough time to go through all submitted questions live during the webinar. In this article you will find our answers to the que...

Supply Chain

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Article How OnLocation Analyzes the Impact of Renewables and Energy Storage on the U.S. Power Grid

Article Using Machine Learning in AIMMS for better Decision Making

Article Analytics to the Rescue: Join AIMMS' N.S. Krishnan at INFORMS' Virtual Regional Conference

Article Suggested reading: Academic paper about Constraint Programming with AIMMS

Article Webinar (follow-up): Resilient Supply Chain Network Design

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