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68 Topics

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)

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)

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)

Global Optimization Solver Lower-Upper Bounds

Dear AIMMS Community: I am using BARON solver to solve a continuous non-convex optimization problem. In small cases, I can see that BARON is finding the global optimum and wherever it is verifiable I am verifying that the results are consistent. So I believe my current modeling is correct. Howev...

Developers (Math, OR, programming)

COVID-19 relief efforts: pro bono support.

Dear all, I write on behalf of baobab soluciones, an AIMMS partner based in Madrid. Since the onset of the pandemics we have decided to support organizations and public authorities and offer our solution development services pro-bono for crisis relief projects. We were thinking route optimisation,...

Supply Chain

CaseCreate Error

Hi! I have just build my first model on AIMMS and when I tried to run the model, the next following error appeared: If the option “Data management style” is set to “Disk files and folders”, the procedure CaseCreate is not valid. Would anyone know how I can solve this problem? Thank you very mu...

Supply Chain

Indexing a variable with an initial value or constraint

Hi everyone. I'm starting with Aimms, I have two questions First How can I index a variable with an initial value or constraint? . For example X (i) is the dependent variable of the set (for example 4 things) with index i. And what I need is X (1)> = 50 X (2) <= 250 Variable X { Index...

Developers (Math, OR, programming)

Article Study 6

Study 6: Accelerate Adoption of Relevant Customer Channels This study can help you ensure resource requirements in your supply chain. Impact – A very likely scenario is an accelerated adoption of certain customer channels, for instance online grocery. These channels might not be able to bear th...

Supply Chain

Article Study 5

Study 5: Refine Capacity Smoothing This study can help you ensure resource requirements in your supply chain. Impact – As certain resources are forced to close, other resources will experience an increased load. Companies may not be able to adequately ramp up capacity and lose sales. Action –...

Supply Chain

Article Study 4

Study 4: Create Multiple Plans for Resource Utilization This study can help you ensure resource requirements in your supply chain. Impact – Manufacturing plants and warehouses will experience a sudden shift in resource utilization. There will most likely be a reduction in labor hours as fewer pe...

Supply Chain

Article Study 3

Study 3: Identify Optimal Sourcing Locations This study can help you anticipate shortages in your supply chain. Impact – As transportation lanes become unavailable, the availability of suppliers and components will decrease. Action – There is a strategic incentive in understanding the optima...

Supply Chain

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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

Article Study 6

Article Study 5

Article Study 4

Article Study 3

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