Common interests

76 Topics

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

Warning: Model is not yet optimal

Hello, I have implemented the simple nonlinear problem in AIMMS which uses the CONOPT 4.0 solver to solve it. But whenever I run the code, the objective function value changes and I get the warnings like: "Warning: After 252 iterations CONOPT 4.0 terminated and BasicStateEstimation is not yet o...

Developers (Math, OR, programming)

Multi-depot VRP

Hello Team, I am working on the multidepot-VRP problem an extension of your practical example capacitated VRP. I want to make a model in which vehicles will depart from their depots to serve different customers and turn back to the same depot where it started from. I made a rough model but facing so...

Supply Chain

Extended formulation returns infeasible

Hello everyone, I am currently working on a Supply Chain problem (LS-U-B) and I am facing some issues that I can not solve. I have a standard formulation where the objective funtion is to minimize the total costs (Inventory and Backlog). The “classical” flow constraints are: Intenvory(s-1) + Produ...

Developers (Math, OR, programming)

Robust Optimization

Hi, After building a deterministic model, I constructed the robust counterpart of the model. I defined an uncertain parameter and I called the GMP GenerateRobustCounterpart. The model seems to be running without errors,however, it does not provide any result. It seems like the variable (vAllcocati...

Developers (Math, OR, programming)

Article Webinar: Analytics for a Better World

Join the second Analytics for a Better World Webinar (ABW-W) Wednesday - May 27, 2020 17:00PM-18:00PM Central European time 8:00AM-9:00AM Pacific time 11:00AM-12:00PM Eastern time Speakers:Koen Peters, Head of Development for Supply Chain Planning at World Food Programme (WFP) and PhD at Z...

Supply Chain

Excel

I am a beginner. I have created my model and now I need to read data from Excel. I have tried following the “ReadingExcelData.ams” example and specifically AXLL, but it doesn't work and keep getting this error: “The first argument of internal procedure "ReadUsingAXLL" must be an explicit identifier....

Developers (Math, OR, programming)

Article Webinar: How to improve the adoption of Robust Optimization by practitioners

Join the next Robust Optimization Webinar - ROW Talk! Date: WEDNESDAY, May 20, 2020 Time: 9.00-10.00 Boston time, 15.00-16.00 Dutch time, 21.00-22.00 Singapore time. Featured speaker: Dick den Hertog (Tilburg University, Tilburg, The Netherlands) Panelists: Aharon Ben-Tal (Technion, Haifa, I...

Developers (Math, OR, programming)

Linear Programming exercises

Came across a nice set of (3) Linear Programming exercises from the Erasmus University of Rotterdam (academic year 2016/2017) that might interest you. https://www.studeersnel.nl/nl/document/erasmus-universiteit-rotterdam/lineair-programmeren/verplichte-opgaven/exercise-set-aimms-16-17/999425/view

Developers (Math, OR, programming)

Article Supporting the Dutch Healthcare System with AIMMS-based Optimization During the COVID-19 Pandemic

This article is based on an interview with Erwin Hans, Professor of Operations Management in Healthcare at the University of Twente and Co-Founder of CHOIR and Rhythm B.V. Erwin is helping care givers address the challenge of critical care capacity and is looking for motivated students with AIMMS kn...

Developers (Math, OR, programming)

Warning: Model status 13: Error no solution, Solver status 9: Error: Setup failure (see message window).

Hello everyone, I am currrently doing a project for my university and I have this type of error : CPLEX cannot handle MIQCP models with quadratic equality constraints like 'BtoWCosts_definition(91789)'. I checked all my variables and my constraints but couldn’t find any “quadritic” ones. And the...

Developers (Math, OR, programming)

Reading excel data

Hi, I have built my first AIMMS model and it is running without any errors now. However, it does not read my excel data and therefore I do not get any result. I was wondering what could be the problem. Do I need to save the project and the input excel sheet in the same folder? Thank you very muc...

Developers (Math, OR, programming)

Ant-Colony Optimization

Dear All, I want to develop Routing Problem Model using Ant-Colony method, does AIMMS possible to generate the method? Are there any example that anyone could share..? Thank you very much

Developers (Math, OR, programming)

1
2
3
4

Page 1 / 4

Article Suggested reading: Academic paper about Constraint Programming with AIMMS

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

Article Webinar: Analytics for a Better World

Article Webinar: How to improve the adoption of Robust Optimization by practitioners

Article Supporting the Dutch Healthcare System with AIMMS-based Optimization During the COVID-19 Pandemic

Sign up

Login to the community

Scanning file for viruses.

This file cannot be downloaded