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I want to to solve several instances of a model with modified input data. This varied input data usually only affects the coefficients; but, it might affect the number of variables and constraints as well. Ideally, the varied instance of the model should use a warm start from the last solution to reduce run-times. I am a bit familiar with GMP functions. However, I am not sure how to effectively implement such procedure. I was wondering if AIMMS has something similar to Gather-Update-Solve-Scatter (GUSS) syntax in GAMS. I would appreciate your comments :)
Hi, I'm Anne here. Im tackling a problem on producing a food menu fulfilling optimal salt intake for every day. The result will be in table form. I have obtained the result on this problem, but now the new problem Is I was supposed to obtain a new table where it shows all the food for all meals (breakfast, lunch, tea, dinner) and for 5 type of patients (normal, hypertension, heart failure, Chronic kidney disease, diabetes) for all 7 days in a week and I'm detail the table should display each food's recipe in the end result. I already declare set of ingredients, and in parameter select the ingredients for the food it belongs to, add the new index set in all areas of constraints and at the decision variables and I run. But it shows main execution could not provide integer solution and it's infeasible. What else I should be correcting?Note: Solving using linear programming model in AIMMS.
Hi,I was a production planner at a rotational molding factory, and now I try to model this environment in Aimms by using the example of the machine shop scheduling problem.For my model I only need one extra ‘dependent’ variable → a variable that tracks starts and ends of products on a machine. The reason is that starts/ends of a product on a machine involves set-up cost, and I want this to be a penalty in the TotalCostOfStartingOrders.So I created the binary variable DoYouStartOrRemoveAProductFromAPosition(m,a,s,p,pn,i_dc), in where m is the machine (2 machines), a is the arm (each machine has 3 arms), s is the side of de arm (each arm has 2 sides: up or down), p the position (each side has 3 positions), pn is the product name (the model contains 12 products) and i_dc is the daily calender in workdays (66 workdays).This binary variable is defined by three contraints:DoYouStartOrRemoveAProductFromAPosition(m,a,s,p,pn,i_dc)<=(DoYouHaveProductionOfAProductInAPeriod(m,a,s,p,pn,i_dc) + D
Hello, I am a beginner at using AIMMS and have my sets, parameters and variables all sorted out. I am, however, stuck with one constraint. I have a variable x(p) (so x(p) needed) and parameter d(p) (max capacity (p)) and want to have a constraint x(p) <= d(p), but without havin to use a sum. How do I so this? Thank you.
This example tackles the growing challenge of optimally placing and sizing electric vehicle (EV) charging stations in urban environments. With EV adoption rising, particularly in the United States, the need for accessible and cost-effective charging infrastructure is critical. Many EV owners rely on home charging, but the availability of well-positioned public charging stations supports market growth and alleviates "range anxiety," where drivers worry about running out of power before reaching a charger. The goal is to maximize accessibility and minimize infrastructure costs, taking into account location density, demand patterns, and geographical constraints. To address this, the example uses the Vulture algorithm, a Particle Swarm Optimization (PSO) method adept at solving non-linear, non-convex problems in continuous spaces. By effectively planning charging station deployment, urban planners can enhance EV infrastructure, helping cities advance toward sustainability goals and facilit
Hi, I’ve been doing my project on course scheduling. However, I’ve encountered problem listed below:My obtained result did not follow my parameter and constraint.Figure below shows the parameter for Group_Classes, for instances, MDA3033_G1_1, MDA3033_G1_2, MDA3033_G1_B1, MDA3033_G1_B2, and MDA3033_G1_B3 are belong to students group under program Analytic Data (Year 2). So i ticked all the boxes that belong to the students group respectively. Then, my on the second figure, it shows my constraint for Conflict_Student. But, when I executed AIMMS, it gave me results like Figure 3. As u can see, in Figure 3, MDA3033_G1 and MDA3044_G1 shared the same students group. So there’s still conflicts between those two subjects. MDA3033_G1_1 & MDA3033_G1_2 are assigned to t=45,46, meanwhile MDA3044_G1_B1 , MDA3044_G1_B2 & MDA3044_G1_B3 are assigned at t=46,47,48. The conflicts occurred at t=46. Can anyone explain to me which part did i do wrong?Figure 1Figure 2Figure 3
Hi, I created a gantt chart that to display p_taskStartTimePerEmployee(i_task,i_employee)p_taskDurationPerEmployee(i_task,i_employee) How can I show the task number or name on top of each task bar like the in the below photo (this photo taken from aimms help not my model)? For example I'm interested in showing i_task value on top of each task bar.thank you inadvance
One of the most frequently asked questions in the process industry is whether a given stream is measured by volume or weight. With AIMMS, this can be easily determined by examining the unit of measurement (UoM) assigned to the stream. In AIMMS, UoMs are managed as data and stored in what are known as unit parameters.For example, consider three streams: a, b, and c. The units for these streams can be specified in AIMMS as follows:data { a : [kg], b : [ton], c : [m3] }To determine if a stream is a weight, you need to check if its UoM is commensurate with the base unit of weight. Assuming we have a function fnc_isCommensurate(up_a, up_b), you can use the following expression:fnc_isCommensurate(up_strUnit(i_stream), up_baseUnitWeight)This will indicate for each stream whether it is measured by weight.Using the AIMMS intrinsic function AtomicUnit, the fnc_isCommensurate function can be implemented as:fnc_isCommensurate := AtomicUnit(up_a) = AtomicUnit(up_b);
Machine efficient data sources often identify objects via numbers. Human friendly representations of same data uses names instead. When exchanging data with both machine efficient data sources and human friendly data sources translations are common.The attributes binds-to-display-name and range-display-name, introduced with AimmsDEX 24.6, facilitate translations between element representations, for instance a translation from number to name and visa versa. InterfaceThe running example uses locations and connections, and its interface looks as follows:The locations are actually numbers, and the annotation webui::ElementTextIdentifiers translates these numbers to names in the UI. InputThe input is in SQLite tables, such as: The input identifies each location by its number, and has a name as attribute Writing Excel directly: With this data, it can be directly written to an Excel sheet.The mapping file this table looks as follows: And the corresponding data sheet that comes out of i
The other day a customer was asking about the statements empty, cleanup, cleandepedents, and rebuild. In addition, that customer wanted advice on memory management when running multiple data instances for the operations research problem at hand.These two questions will be handled in two subsections below.Quick overview of some data management functions. If S is a set, index i in S, and parameters P(i), Q(i,j) exist,then the statementEmpty S ;will remove all data from S, P, and Q.There is a variant of the Empty statement that operates onsubsets of AllIdentifiers. Let the set sIds, subset of AllIdentifiers, be { P, Q }.Then the statement:Empty sIds ;is implemented as emptying the data of P and Q, not of sIds.Additionally, if S used to be data { a, b }, but is now { b },and P used to have data { a : 1, b : 2 }then:('a':1 ) is called an inactive element of P.To remove the inactive data in P, there are two alternatives:Alternative 1. The statementCleanup P ;will remove the inactive data fr
Hi community,we have the below (screenshot) calendar identifier in AIMMS and are writing data indexed over iWeek (elements of the form "w44-2024") to Parquet files using DEX. Now, whenever DEX does this for us, these elements are written to the Parquet file as "2024-10-28 01:00:00" instead, looking like a datetime object being the first time instant of this week. Similarly, for months, a datetime object is written being the first time instant of this month. However, when reading in these Parquet files again using DEX, with the same mapping, these month elements are read in correctly while the week elements are not. I.e., the element "2024-10-28 01:00:00" above cannot be mapped back again to "w44-2024". We would be interested to hear any best practices regarding reading and writing calendar elements using DEX and if we are overlooking something here. Thanks!
Hello everyone!I’m reaching out to know how can I use multiselect in showing nodes and arcs in my network map. It is part of my project to make the UI interactive, however, I’m having difficulty doing so. I have tried testing if the same multiselect-table interaction can also work here, but it doesn’t. Any tips or examples you can provide?Thank you!
When displaying a gantt chart, the colors of the jobs come from the standard 16 color palette as far as I can see.For example, when I have a gantt chart defined on pGanttChartJobStart(iJob, iSku, iLine) and pGanttChartJobDuration(iJob, iSku,iLine) and in the gantt chart the iLine is corresponding to the resources and the combination (iSku, iJob) are corresponding to the jobs.If I understand it correctly, AIMMS will take the coloring from the first component in the Jobs section, which is exactly what I want (i.e. every job for a given sku always has the same color, namely the ‘sku’ color) However, sometimes, this results in two jobs that are consecutive on one line, but have colors that are quit close to eachother.I know I can easily create my own annotations and define my own colors for that with CSS, but then I will have lost the connection to the standard aimms palette. Do you know if it is possible to define custom annotations and in the CSS for those annotations indicate you want t
Hi community,I’ve noticed that the WebUI filtering applied to table widgets persists through AIMMS PRO sessions (even if they are closed). Is this filtering user dependent and is there a way to reset this default filtering of a deployed AIMMS PRO app?Thanks!Dani
Hello, I am in need of urgent help because my entire WebUI is gone because of an error code for grid sizing, do you know how can I address this?
In this practical example, an efficient plan is developed for delivering large cargoes using oil tankers. The model assumes each ship can carry only one cargo at a time, and once the time horizon begins, all vessels head directly to the loading port. Upon loading, each vessel proceeds directly to the delivery location within its designated time window. Constraints include ensuring each cargo is loaded inside the determined time window, each cargo being transported by only one vessel, and each charter vessels being assigned to only one route at a time. The objective is to minimize costs associated to combinations of cargoes and routes. Click here to download the full project! Reference: Gustavo Diz, Luiz Felipe Scavarda, Roger Rocha, Silvio Hamacher (2014) Decision Support System for PETROBRAS Ship Scheduling. Interfaces 44(6):555-566.
Hi all,I’ve seen here and there some things mentioned on the following items below, but I lost track on the latest developments. Can someone share a status update on them?Have the capability to specify file decimals per identifier (instead of per widget) ? Support for unit (parameters) in WebUI ? Library support for WebUI , i.e. that some WebUI parts / pages become shareable across different AIMMS apps Visible/hidden option per identifier in widget settingsDepending on this I might post an improvement idea for the backlog.Thanks,Joost
Hi,I am working on a University Examination Timetabling Problem (UETP) using Binary Integer Programming, and I am running the model in AIMMS. The model is taking an unexpectedly long time to solve.Previously, I set the optimality relative tolerance to 0.01, and while the results were not 100% optimal, I was able to obtain optimal solutions in a reasonable amount of time. However, when I set the optimality relative tolerance to 0, the model has been running for an extended period. After 5 to 9 days, the gap was 0.38%, and after 10 to 16 days, the gap only reduced to 0.37%, this model still running.I ran this model on two different machines to compare performance, and both showed similar results:Server: Intel(R) Xeon(R) Silver 4214 CPU @ 2.20 GHz (2 processors), 16 GB RAM, Windows 10 Pro Desktop PC: 13th Gen Intel(R) Core(TM) i7-13700 @ 2.10 GHz, 64 GB RAM, Windows 11 ProMy questions are:What could be causing such a long execution time with this model? Are the specifications of these mac
Our users want to be able to store case files locally on their computer and reupload to the cloud environment at a later stage. It looks like the WebUI data manager does not support this requirement. What is the best way to enable users with such a feature?
Hello Everyone!One more renewed example is live! Come check!This example introduces a knapsack problem. The example considers a data set of 16 items which can be included in the knapsack. The objective is to maximize the accumulated value of the items. The number of items is restricted by the maximum weight that can be carried in the knapsack.We used a lot WebUI new features, you can find the full example app here. Feel free to use this thread to anything you need about this example.
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:
This week, our partner CQM published a great use case on "valorization." The article is in Dutch, so I asked ChatGPT to translate it.https://cqm.nl/nl/cases/vips-maakt-planning-vion-datagedreven In agriculture, food production, and food processing industries, "valorization" is crucial. It increases the value, utility, or profitability of a product. In the meat processing industry, this means utilizing every part of the animal as efficiently as possible and making the most out of the meat. It’s a highly complex process with many variables. Together with meat producer Vion, CQM developed the VIPS application, which has made Vion's planning data-driven.Vion Food Group's largest production site is located in Boxtel. Vion is an international producer of meat, meat products, and plant-based alternatives. From this location, fresh meat and processed meat products are supplied to national and international retailers, food service industries, and the meat processing industry. Due to their scale
Hi, everyone! I’m trying to import a parameter based on a excel sheet. The cell is empty and the parameter is set with a default value of inf, but the parameter keep assuming value of zero. There’s anything that I can do to, if the cell is empty, the value assumed be different than zero?I don’t know if this should happen or if it’s an issue that has already been fixed. I’m using the verison 4.85, by the way. Thank you very much!
Hello! I was writting to see if anyone would be able to help me; you see, when I start up my AIMMS project file I get an error (which can be seen on the shared screenshot) about missing some kind of element in my project library. This started happening after moving my AIMMS project files from one computer to another, so I suspect that some data might not have transfered properly. In any case, I was hoping someone would be able to help me, as this is kind of urgent to be honest. Thank you very much in advance! Pablo
