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Academics using AIMMS

A dedicated space for academics and researchers to connect, ask questions, share research insights, and explore academic opportunities with AIMMS.

211 Topics
Jess Es
Jess EsGrand Master
published in Academic News & Opportunities
How to cite AIMMS in a publication

If you use AIMMS software for publications in scientific research (e.g. for the Academic Community), please reference it as shown in our guidelines below.AIMMS Developer (typical academic use) Cite version number and year of release. This can be found in the “About AIMMS” menu item in AIMMS IDE.Example:For this publication, the AIMMS software, an optimization modeling platform, was used. AIMMS version 4.74. Copyright © 2020 AIMMS B.V. All rights reserved. AIMMS is a registered trademark of AIMMS B.V. www.aimms.com   AIMMS PRO Platform Cite version number and year of release. This can be found in the “About” page in the AIMMS PRO portal.Example: For this publication, the AIMMS PRO software, an optimization deployment platform, was used. AIMMS PRO Platform version 2.34. Copyright © 2020 AIMMS B.V. All rights reserved. AIMMS is a registered trademark of AIMMS B.V. www.aimms.com  AIMMS Cloud Platform (fully managed AIMMS PRO) Cite version number and year of release. This can be found in th

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Jess Es
cmurray3
cmurray3Enthusiast
published in Research & AIMMS Questions
Help us test a new tool to automatically generate AIMMS code

Hi, Community members, I'm excited to share a new online tool that has been developed by Dowon Lee, a graduate student in Industrial & Systems Engineering at the Univ. at Buffalo, with the generous support of AIMMS. tex2solver generates AIMMS code from LaTeX, or even pictures of an optimization model.  In addition to generating AIMMS code, tex2solver also works with Python (using the PuLP package).   I'm posting to the Community forum:To publicly thank AIMMS for their support of this project; To let the AIMMS user community know about the free tex2solver tool; and  To ask for your assistance to help us test tex2solver.Regarding the last point, tex2solver is still in its development phase.  Your feedback is very valuable to help us find bugs and add new functionality.  Registration is easy (and free) at https://tex2solver.com.    In return, we hope that tex2solver helps streamline your workflow from conceptualizing a model to solving it in AIMMS...like this:   Happy optimizing,-chas

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cmurray3
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kira.west2020Enthusiast
posted in Research & AIMMS Questions
AIMMS academic license not found

I'm having trouble using an academic license on a machine that previously used it. I now get an error: “failed to get AIMMS license” though I have checked that my license is still valid and my machine is connected to the internet. Any idea what might be happening?  

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aleksandar.velkov
AIMMSian
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hariharangatechEnthusiast
asked in Research & AIMMS Questions
Long .ams file - AIMMS MOPTA

Hi, So I have a very long model(.ams file) of 14MB. It is taking forever for the model to create and run. The window is always in a not responding mode and the status always stays in compiling. Can anybody help me get this long model running?Immediate help would be appreciated. This is the scalar version. Thanks 

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Chris Kuip
AIMMSian
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hugo.fabrisExplorer
asked in Research & AIMMS Questions
Access to AIMMS 4.90 for Legacy Project Conversion from AIMMS 3

Hi everyone,I'm currently working on an academic project that requires accessing and adapting a legacy model originally developed in AIMMS 3. When I try to open the project using the current version (AIMMS 25.4.2.1), I get a message saying I need to first open it in AIMMS 4.90 or earlier to convert it to the new format.Would anyone happen to have access to the AIMMS 4.90 installer (or the latest version prior to it that supports AIMMS 3 project conversion)?Also, does anyone know if a license tied to version 25.4.2.1 is compatible with AIMMS 4.90? Or would I need a separate license for that? If so, how can I ask for it?This is for academic, non-commercial research. Any help would be much appreciated!Thanks in advance,Hugo

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gabiservidone
Administrator
Vasilakakis Konstantinos
Vasilakakis KonstantinosEnthusiast
asked in Research & AIMMS Questions
DIET PROBLEM IN INTERVAL ANALYSIS

Hello, I would like to turn the diet problem into a problem that can be solved by defining the results in the logic of interval analysis. To outputs results within an interval and not in absolute value. Let's say nutrients and costs for a beginning.Is there a sample of some problem that solves in aimms with this logic so I can study it? Sincerely,Konstantinos Vasilakakis, PostDoc

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Vasilakakis Konstantinos
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JacopoExplorer
asked in Research & AIMMS Questions
How to create a new set which is a transformation of a previous set

Basically ill provide here the formulation:We have set t →       t ∈ T = {1,2,...,tn}           ∀t ∈ TAnd we need to create and use set tau where tau stands fortau →      ∀τ =t+1,...,min(t+Li −1,tn) Please, it would be so helpful if someone could provide a solution. Thank you so much.

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luispinto
AIMMSian
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SheebsPatsExplorer
asked in Academic News & Opportunities
MOPTA 2025 Question

Some of the files shared are json files and aren’t accessible.I also tried to look up pre-existing files and the tutorial for beginners after installing the software, but it throws an error. How do I proceed as it is my first time using AIMMS and the deadline is nearing 

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AIMMSian
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kimia moosavianEnthusiast
posted in Research & AIMMS Questions
Results

Hello community,I’d really appreciate some help as I’m quite lost. I'm trying to optimize a bi-level system where:The upper level maximizes the leader’s profit. The lower level minimizes consumer costs in an integrated energy system.I received this model from another PhD student, and it should work reliably with three energy types: gas, electricity, and hydrogen. However, I keep getting negative profit in all cases.Following my professor’s guidance, I’m analyzing cost sources to understand why production continues despite negative profits. It seems our revenue doesn’t cover costs such as maintenance, CO₂, investment, and exchange costs.To troubleshoot, I set system capacity to zero to force no production or at least reach a positive result, but it hasn’t worked. Any insights on how to go on? Thanks a lot

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deannezhang
AIMMS Champ
Wanie Saidi
Wanie SaidiEnthusiast
posted in Research & AIMMS Questions
Clarification on Optimality Gap and Multi-Objective Handling in AIMMS for University Exam Timetabling

I am currently working on a university examination timetabling problem to produce an effective final exam schedule that considers student and lecturer complaints as well as basic scheduling requirements. Upon execution, AIMMS provided a solution with 99.02% optimality, indicating an optimality gap of 0.08% (showed in the progress window). I have a few questions to better understand this result.(1) What exactly does it mean by optimality gap. Does a 99.02% optimality indicates that the solution meets all hard constraints included and is 99.02% optimal relative to an ideal solution? How is this percentage determined. We are curious about whether AIMMS has checked every single hard constraint. (2) Our problems involve 3 objective functions. We are interested to know how AIMMS handles multiple objective functions. Does it calculate each objective function separately or simultaneously? How does this impact the overall optimality percentage? Which objective function might AIMMS be prioritizi

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Wanie Saidi
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RwitamJEnthusiast
asked in Research & AIMMS Questions
Index issues in a Cutting Stck Model

Hi,I have written one cutting stock model, the constraint is that cutting width should not exceed mother coil width. The indices are mc (mother coil number), mct (mother coil type), bct (baby coil type). Two different bct can be slitted from a same mc and mct.The constraint is thatIndexDomain: (mc,mct)|pMotherCoilTonnage(mc,mct)>0sum[(bct)|pBabyCoilQuantity(bct)>0,vNosBabyCoilMotherCoil(mc,mct,bct)*pBabyCoilWidth(bct)] <= (pMotherCoilWidth(mc,mct) - pTrimLoss(mc,mct))*vMotherCoilSlit(mc,mct).Now the problem is my parameter on trim loss pTrimLoss(mc, mct) is dependent on mc, mct and bct. The trim loss of a ‘mc’ will be differnet for two different bct. I have taken the parameter as pTrimLoss(mc,mct, bct). I am unable to fit it in the constraint. How to address it. 

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R
Wanie Saidi
Wanie SaidiEnthusiast
posted in Research & AIMMS Questions
Prolonged Execution Time for University Examination Timetabling Problem in AIMMS

Hello,Excuse the long explanation below. We are trying our best to make you understand the whole problem.I am a Masters student currently conducting research on the University Examination Timetabling Problem (UETP) using Binary Integer Programming. The problem is the same examination problem whereby it is to assign exams to suitable slots and venues accordingly to the requirements stated (hard constraints). The number of exams to be assigned, the number of slots available, the number of rooms available are declared as SETS. Also, the same goes for the parameters such as the capacity of each room, students taking specific exams, specific courses that requires 2 hours or 3 hours of exams and etc are known in advanced. We have successfully formulated all the constraints into BIP. Just to let you know that we are executing all models through AIMMS.Below are the constraints and objective functions involved in the model:Constraints: (numbers of constraint below will be used in the table give

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Wanie Saidi
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Mitosz01Enthusiast
asked in Research & AIMMS Questions
OCTERACT error: [json.exception.parse_error.101]

I have run into the following problem, when I was trying to solve my MINLP model. The error massage is the following“OCTERACT error: [json.exception.parse_error.101] parse error at line 1, column 1: syntax error while parsing value - unexpected end of input; expected '[', '{', or a literalWarning: Model status 13: Error no solution, Solver status 9: Error: Setup failure.Warning at line 1 in user-defined function section "MainExecution":Model status 13: Error no solution, Solver status 9: Error: Setup failure.OCTERACT error: [json.exception.parse_error.101] parse error at line 1, column 1: syntax error while parsing value - unexpected end of input; expected '[', '{', or a literalWarning: Model status 13: Error no solution, Solver status 9: Error: Setup failure.Warning at line 1 in user-defined function section "MainExecution":Model status 13: Error no solution, Solver status 9: Error: Setup failure.”The strange thing is that with another solver that my teacher got “BARON” it runs just f

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nelson.limaExplorer
asked in Research & AIMMS Questions
Doubts about how to declare specific parts in the definition field

Dear colleagues, I would like to ask for your assistance in order to declare specific parts in the definition field. I have three doubts:1) How to implement a sum in definition in AIMMS in which one of the variables does not start from the first item?Example: i=14j=16(Cprod.Pi,j+Cest.Ei,j)+j=26(Caum.∆Pi,j++Cred.∆Pi,j-) 2) How to implement an expression in definition in AIMMS that considers operations with two subsequent items (in different times)?Example:  Ei,j=Pi,j+Ei,j-1-PDi,j 3) How to implement a value assignment for a specific indexed item in definition in AIMMS?Example: P1,6=1500 Thanks for you assistance.

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Chris Kuip
AIMMSian
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ccfcuentoEnthusiast
asked in Research & AIMMS Questions
Extracting an index from a variable

t = time indexM = vehicle indexI = supply nodeJ = intermodal nodeI have a variable with (t,M,I,J) index which determines the number of units delivered to a specific node. However, I want to determine the time of delivery of each set of units as a separate variable. Thus, it’s like extracting t from the variables (t,M,I,J). How do I approach this?Thaank you!

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gabiservidone
Administrator
Wanie Saidi
Wanie SaidiEnthusiast
asked in Research & AIMMS Questions
AIMMS License

Hi.I am currently using AIMMS software for my research and have a query regarding the usage of the license I received from AIMMS. Could you please clarify how many machines a single AIMMS license can be used on? Is there a limit to the number of machines where the license can be activated?Thank you in advance for your assistance.

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D
AIMMSian
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Julia ZimmermannExplorer
asked in Research & AIMMS Questions
Help on Vehicle Routing Problem

Hey everyone,I'm working on a vehicle routing problem (VRP) project where the routing will involve more than one company, and customers may have orders from more than one company. So, the idea would be for the companies to collaborate with each other, and the customer would receive just one delivery.Given the larger set of available companies, I need to use in my constraints subsets that contain only the companies used for each customer. For example, if I have three companies, A, B, and C, how can I create a set with only companies A and B for customer I, another set with companies A and C for customer J, another set with only company B for customer K, and so on?My idea was to create a binary parameter, 1 when the customer requests that company and 0 otherwise. But can I write this parameter in the set definition? I thought about using if and else, but I'm having trouble because the parameter depends on two variables (customer and company) and the company set only on one (company).I'm

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gdiepen
AIMMS Champ
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ChiaraExplorer
posted in Modeling for Impact
KES Conference Session - Intelligent and data-driven decision making in green urban mobility

Dear colleagues,we are welcoming submissions to the invited session titled “Intelligent and data-driven decision making in green urban mobility” that is organized within the KES International Conference Sustainability in Energy and Buildings. The conference will take place in Santa Cruz, Madeira, Portugal, from the 18th to the 20th of September 2024.This is the Invited session link with details: http://seb-24.kesinternational.org/cms/userfiles/is05.pdfAnd this is the link to the conference website: http://seb-24.kesinternational.org/index.php Deadline for papers submission is: 13th May 2024 The conference proceedings will be published by Springer as book chapters in a volume of the KES Smart Innovation Systems and Technologies series, submitted for indexing in Scopus and Thomson-Reuters Conference Proceedings Citation Index (CPCI) and the Web of Science.For more information on the invited Session please contact: chiara.bordin@uit.no Kind regards,ChiaraAssociate ProfessorUiT, The Arctic

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kin006Enthusiast
asked in Research & AIMMS Questions
Solving time Octeract and Gurobi

Hello!I have a MIQCP problem that I solve in AIMMS. I have tried to solve it both with Octeract and Gurobi. I solve the same problem with different data sets.For one of the data sets, the solving time for Gurobi is 319 seconds and the gap is 0%, while after 1 hour of solving with Octeract the gap is still 420%.For another data set, the solving time for Gurobi is 1834 seconds and the gap is 0%, while after 1 hour of solving with Octeract, the gap is still 9000%.Does this sound reasonable? I am not that familiar with how these two solvers work, but I thought it was a bit strange that the two solvers give very different results.Thank you in advance :)

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Marcel Hunting
AIMMSian
gabiservidone
Administrator
gabiservidoneAIMMSian
published in Academic News & Opportunities
16th AIMMS-MOPTA Optimization Modeling Competition

Would a Fully Renewable Energy Grid benefit from adding Green Hydrogen as a Supplemental Power Source? To meet decarbonization targets, renewable energy technologies need to be integrated into electricity and gas grids on a large scale. The energy grid baseload needs stability that renewable energy sources cannot always provide. Decarbonizing the grid requires that coal and natural gas no longer provide baseload support to the energy grid. To operate a fully renewable energy grid, the baseload must be supported by a stable energy source. Green hydrogen could play a key role in decarbonizing heavy industry, as well as supporting baseload power. To design a fully renewable energy system, green hydrogen electrolyzers and fuel cells could be used to support the integration of intermittent electricity sources, namely, wind and solar.See the full problem description for more information:Problem Description: MOPTA_2024_Competition.pdfStarter Project and Data files: Microsoft OneDrive that con

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gabiservidone
Administrator
J
Jingfan LiuEnthusiast
asked in Research & AIMMS Questions
Whether Set and Element associated with a stochastic Paramater can be use in stochastic optimization

“outage_status(cd)” is a stochastic Paramater, and “outage_units(cd)” is a set and colects u if  “outage_status(cd)” >0. I wonder whether the data of set “outage_units(cd)” will change with the variable “outage_status(cd)” in different scenarios.   

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Marcel Hunting
AIMMSian
X
XinhuiEnthusiast
asked in Research & AIMMS Questions
Resource balance for resource transport between zones

Hi AIMMS community! I’m currently working on a resource transport model using AIMMS and I've encountered a symmetry challenge for resource balance between zones.In the case when I would like to transport 200MW of power from zone 1 to zone 2, the net outflow of power from zone 2 must be equal to the net inflow of power into zone 1, which can be represented by the equation below:F_in (z,z’) = F_out (z, z’)whereby F_in (z,z’) is represented as the net inflow into zone z (zone 1) from zone z’ (zone 2);while F_out (z,z’) is represented as the net outflow from zone z (zone 2) to zone z’ (zone 1).Does anyone know of an AIMMS function that can seamlessly handle this equation? Any insights or tips are highly appreciated! Thanks so much!

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Dana.PnsgExplorer
posted in Research & AIMMS Questions
Trace the calculation path for the result of the target function

Hello Everyone,I have integrated a vehicle routing problem in AIMMS and was able to solve the model with a case study. I can display the result of the minimized objective function in the Page Manager using a scalar. How can I understand the calculation path for this result? Can I see somewhere which partial results have been calculated for the individual routes or can I display the complete calculation structure? If so, how? Thank you in advance! :)

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Marcel Hunting
AIMMSian
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aaahmedExplorer
posted in Research & AIMMS Questions
Multi Depot Multi Vehicles

I am building a multi depot multi vehicle transportation model. The model is running but gives 0 as optimal.I am just about to introduce the vehicles set and this is where i am having trouble now. I want each depot to have two type of vehicles. This is the best way I can get to right now.  I want a set of vehicle type and a set of depot. I want to tell the model that each depot in this example: depot 1 has 2 scooters, and 1 truck, and depot 2 has 3 scooters and 1 truck. Is there a better way to do this, and how to resolve the error. Attached is my model.   

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Dana.PnsgExplorer
asked in Research & AIMMS Questions
Help Opmization Model Vehicle Routing Constraint

Hi Everyone,I need help in implementing an optimization problem concerning the Vehicle Routing in AIMMS.  I am currently indiciating the constraints for the mathematical problem. The index i and j is for the customers or nodes and k is for the vehicles. I now want to implement the constraint, that each vehicle can only leave the material-depot once. The material-depot i indicated by the value “0” for i or j.  The mathematical formulation is now: sum x(0,j,k) <= 1In AIMMS it is indicated as follows: sum(j, x((0,j,k) <= 1)In this case, the index i is directly indicated with the value 0 for the depot but wenn I integrate this formulation in AIMMS, I receive a warning: “The symbol 0 is not expected”.  How can I indicate this formulation in AIMMS in the correct way so that the system understands that “0” is the value for i?  Maybe someone can help me.. Thank you in advance!! :)  

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gdiepen
AIMMS Champ
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