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Dear AIMMS Team,Trust this meets you well? Kindly assist on the problem explained below and find attached the AIMMS file I am working with. I have a variable StateofCharge(t) in which t is 1 to 24. I want to place StateofCharge(t) at t = 1 or StateofCharge(01) on the conditional statement below. if ( (Charging_Power_kW(01) + SoCMin) > SoCMax) then SocMax elseCharging_Power_kW(01) + SoCMinendif;Note: Charging_Power_kW(01) is put as the value of variable Charging_Power_kW(t) at t=1 While StateofCharge(t) at t = 2,….24 should have the conditional statement below. The index t in the statement applies only from t = 2,….24. If Energy_Difference_kW(t) > 0 then if (StateofCharge(t-1) + Charging_Power_kW(t)) > SoCMax SoCMax else StateofCharge(t-1) + Charging_Power_kW(t) elseif (Energy_Difference_kW(t)) < 0 then if (StateofCharge(t-1) - SoCMin) > Discharging_Power_kW(t) else SoCMinendif; Also, if I have a parameter/variable
Hi,I have the following warning : Usage of directly nested for statements is unnecessary and inefficient.How am I supposed to write this code to avoid the warning ? for gdm::iNode do for (gdm::iTime in gdm::calHorizon) do p1(gdm::iNode):=p2(gdm::iNode,gdm::iTime)*p3(gdm::iNode) ; endfor;endfor; Thank you
Machine shop scheduling problem, how to introduce a binaray variable that shows if you have production?
Dear all,I'm quite new to Aimms, therefore I don’t know if my problem is easy to solve or a difficult one. My end goal is to be able to generate an automated production planning for a big pizza bakery. The machine shop scheduling example is in the direction for what I’m looking for, see the link below. https://how-to.aimms.com/Articles/473/473-ProductionPlanning-machinescheduling.htmlThe machine shop scheduling example determines the optimal machine and start time for each order, so that the makespan is minimized. I want to expand this model, so that more contraints can be added. An important binary variable for me is ‘DoYouHaveProductionInAPeriod(i,o,i_hc)’: do you have production at a certain machine i, for a spefic order o, at a certain time period i_hc. An example of a constraint that I want to add and using the variable ‘DoYouHaveProductionInAPeriod(i,o,i_hc)’ is if I have 4 workers available, only 4 machines can run at the same time → for each i_hc, sum((i,o),DoYouHaveProductionI
I have been trying to import the phasing in capital data which is in the attached Excel file. I have added the identifiers on the attached word file. The data I am importing has numbers which I want AIMMS to convert to percentages.On my side the PhasingInCapital is a worksheet inside the Input Data workbook. Here is the error:ExcelSetActiveSheet(Input Data.xlsx, PhasingInCapital) failed: Workbook doesn't contain the specified sheet. Invalid index.I have imported a lot of data files from Excel, I am not sure what am I doing wrong this time.Please assist.
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 the lot and “simulate” charging an electric vehicle. → i tried to find a solution in the community, but i was not successful. Is there any possibility, any constraint which could make the robot not to service/drive to that parking lot while Demand(i)=0. As you can see in the picture: even if i put Demand of almost every parking lot=0, the robot drives to all the places, before going back to the depot. Another problem is, that i want to make the robots drive on a specific route, shown as yellow in the picture/simulation. → Is there any chance of making the robots drive a minimum besides the yellow route? My thought is that, despite being able to create that, later in the mathimatical pr
Dear All, I want to model the power of wind turbine under different wind speeds with respect to the cut-in, cut-out and rated speeds. How can this be implemented in AIMMS. Please, kindly make your response comprehensive as i am new to AIMMS. Thank you. All the terms have been declared as parameters.
In this how-to article a hello world style introduction to leveraging a REST API with an OpenAPI specification is presented. The complete example can be found here.That article discusses creating the attached application. This application can be opened using the AIMMS Community edition. After obtaining an API key from ipTwist, and filling in my own IP address it shows me a location in the Netherlands:
Hi all,I’m sorry of the question is too basic, but I recently had to re-run an old code (originally developed in AIMMS 4.47) and I’m having lots of trouble correcting errors.I have a variable ( Ireal(ld) ) that uses another variable ( Vreal(bus,ph) ) in its calculation.I have an string parameter ( load_bus(ld) ) that has the “bus” value for each “ld” and a parameter ( load_ph(ld) ) that has the “ph” value for each “ld”.In the old code I used Vreal(load_bus(ld), load_ph(ld)) to calculate the Ireal(ld), but in the new AIMMS version (4.88) I keep getting “The scope of string parameter “load_bus” has not been specified”.Can anybody please help me in what I’m missing?Thank you in advance.
Hi,I am solving a huge MIP (481707 integer variables). I set the relative gap to 0% from CPLEX MIP settings. With such a huge model, the solver should take quite some time to solve. Just after 287466.11 sec (3.3 days), the model stop running and the solver status says 'Terminated by solver' why the gap is 1.27%. Why does this happen? I am attaching a screenshot. I'll appreciate any ideas on this. Thanks !
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 challenges. INFORMS Chicago Chapter and INFORMS Analytics Society will bring together innovative and insightful leaders across multiple industries and education for this annual conference. The goal is to have in-depth discussions and exchanges of experience and ideas related to solutions during these tough and uncertain situations. The conference will take place virtually.Areas of focus include AI & machine learning, epidemic and healthcare analytics, and election analytics. Join us to hear from experts and exchange ideas on mission critical and timely applications, strategies, and processes. Will you attend the conference? Are you working on an OR/Analytics project to help address some o
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 Communities: the NeatWork Tool.Abstract: NeatWork is an optimization and simulation tool for the design of water-distribution systems with the aim of providing clean water to poor rural communities. The management of such systems must be cheap and simple, a requirement which prohibits power-driven equipment, such as pumps, and man-operated devices, such as regulators. Therefore, the physical system must be driven by gravity only. It must also be endowed with self-regulation to ensure flow invariance despite stochastic intermittent water withdrawals by independent users. The formulation as a least-cost design problem belongs to the realm of two-stage stochastic optimization, in which the second stage
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-modeling, which I solved mathematically, into AIMMS. Can you help me with this?
[i]This article, originally published in 2013, comes from our Tech Blog archives. As such, some cited data is a bit dated, but we think that the story's value illustrating practical application of OR still holds up.[/i] [b]The mathematical story behind North Star Alliance’s POLARIS[/b] More than 35 million people worldwide are infected with HIV or are living with AIDS, and approximately 70% live in Sub-Saharan Africa. Mobile populations, such as long distance truck drivers, are particularly at risk of contracting and transmitting the virus. In 2007, TNT Express and the United Nations World Food Programme joined forces to form North Star Alliance (North Star) - a public-private partnership that is working to increase access to health services along major transport corridors in sub-Saharan Africa. ORTEC, a longstanding AIMMS partner, joined North Star in 2008 to design their award-winning Corridor Medical Transfer System (COMETS), which enables North Star staff to access and mo
Hello to everyone, i have the following problem i can not solve. So on the one side I have consumers that need a certain amount of energy at a time. On the other side I have a generator plant that produce green electricity. The Problem is, that the demand can not alaways be satisfied by the generators. For this I use batteries. The are charged, if there is more then enough energy available.The express this mathematically, I used a if then formulation: For the charging I use:Demand(t) - Generator (t) >= 0 → Battery(t) = Battery(t-1)*(1-self-discharge-coeffizient)+((Demand(t)-Generator(t))*efficiency_Inverter*efficiency_Battery)For the dischargingDemand(t) - Generator (t) <= 0 → Battery(t) = Battery(t-1)*(1 - self_discharge_coeffizient)+((Demand(t)-Generator(t))/efficiency_Inverter)Demand(t), Generator(t) and Battery(t) are variables.self_discharge_coeffizient, efficiency are parameters I do not have any clue how to solve the problem in AIMMS. If anybody could help me, i would be v
Adding leading time, phasing in capital and economic life to a generation capacity expansion planning model
Good day, I have an electricity capacity expansion planning model which was developed in AIMMS and is working fine. However, now I need to add the following:Lead times, which differ for each technology. Currently, the model assumes that if a technology is selected by the model, it can produce electricity as soon as the model makes it available for capacity allocation. I need this to change and the model should make the technology’s capacity available after the lead time has expired. Phasing in capital, which also differ for each technology. The current model assumes that the capital for a chosen technology is payable immediately. The phasing in capital are connected to lead times. For example if a technology has a lead time of 2 years, the phasing in capital is also over 2 years, say 90% of capital is payable in year 1 and 10% in year 2. I need the capital for each technology to be phased in according to the phasing in capital percentages. Life of plant (Economic life), which also dif
We are currently exploring opportunities for combining Optimization and Machine Learning through collaboration with the OPTIMAL consortium which carries out a large research project entitled "Optimization for and with Machine Learning".The goal of this project is to provide new analysis and tools for Optimization problems and algorithms arising in Machine Learning, but also to use insights and tools from Machine Learning in order to improve Optimization methods.For more information on the OPTIMAL project please visit the site https://optimal.uva.nlWe will try and provide updates on our exploration through more specific posts on this forum.
From quite some AIMMS app developers we have heard demand for ‘enabling AI/ML’ in AIMMS or ‘Run AI/ML, extending the AIMMS platform’. We have ideas how we could indeed deliver this to you. For example:Making it easy to ‘add’ a Python script/program to your AIMMS project that can be fed with model data and from which the results can be returned to AIMMS identifiers. We can think of various ways to run such a Python script, think of Azure Function or maybe as a Docker container, etc.. Making it easy to call ready-to-use services such as ‘Azure Machine Learning’ from your AIMMS model, including the transfer of model data to and from that service.But before we make too many assumptions and start building functionality, we would like to learn more about your needs and expectations.So please tell us: How do you expect AIMMS to support you in applying Machine Learning and other AI technologies, apart from optimization, in your projects? And there is the broader topic. AIMMS has historically f
Good afternoon!I would like to invite the community to share their favorite blogs on mathematical programming, operations research, and data manipulation.My favorite blog is http://yetanothermathprogrammingconsultant.blogspot.com/The author of the blog uses GAMS. Models created in GAMS can be converted to AIMMS.https://how-to.aimms.com/Articles/312/312-convert-gams-to-aimms.html
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