Optimization Tooling

Customers and users frequently bring up ‘latency’ and ‘bandwidth’ effects when using our Cloud SaaS.This post is intended to provide clarity around this topic based on what we hear from customers using the AIMMS Cloud Platform or SC Navigator.First, what are we talking about?DefinitionsLatency refers to the delay or lag between when a user performs an action and when they receive a response from the application. It is influenced by factors such as the physical distance between the user and the server, the network infrastructure, and the speed of data transmission. Higher latency can result in slower response times and can be frustrating for users, especially when real-time analytics or time-sensitive decisions are involved. Bandwidth, on the other hand, refers to the amount of data that can be transmitted within a given timeframe, the data transfer speed. It is measured in bits per second (bps) or megabits per second (Mbps). Bandwidth determines how quickly data can be sent or received

Dear Community, I've noticed a growing interest among clients in leveraging AIMMS' Rest API and ADLSG2 (Azure Data Lake Storage Gen 2) services. To assist you on this journey, here are some helpful pointers: References: Developing an AIMMS Service: Follow this guide to develop an AIMMS service and integrate it with your applications. Develop an AIMMS Service Setting up an Endpoint in AIMMS: Learn how to configure an endpoint in AIMMS to interact with external services. Creating an AIMMS Server app Providing REST APIs Using AIMMS Services from Python: Explore this article to understand how to utilize AIMMS services from Python scripts. Using AIMMS Services with a Python Application Connecting to and Managing ADLSG2: Discover how to connect to ADLSG2 from within AIMMS and perform file operations. Azure Data Lake Storage Use the AIMMS Cloud Azure Data Lake Storage for integrating data How to access the Azure Data Lake Storage from an external location  Quick-start Guide:Here'

app is working well in development environment. after publishing app on AimmsPro, I see error as page id not found.  

Based on an exercise we conducted with a specific customer recently, we would like to offer a framework for building a potential business case for making the switch from PRO On-Premise to PRO Cloud SaaS.Historic contextIn 2011 AIMMS launched AIMMS PRO, a deployment platform for AIMMS applications. It ran on servers inside our customers’ data centers or cloud tenants.It met customers’ needs for:Easily and quickly distributing AIMMS apps to end-users. Lower Total-Cost-of-Ownership (TCO).In 2016 AIMMS launched the AIMMS Cloud SaaS, delivering AIMMS PRO as on-demand cloud-powered Software-as-a-Service. In addition to the needs listed above, it met customers’ needs for:Security, reliability and scalability Not having to ‘manage IT’After that, all new AIMMS customers opted for this new SaaS solution, the AIMMS Cloud SaaS.Because of this customer preference and because almost all companies now have a ‘cloud-first’ policy, AIMMS made the strategic choice in 2022 to focus innovation on the AIMM

Recently one of our customers encountered a REST API that didn't accept Json UTF8 files starting with a Byte Order Mark (BOM). By default, the PUT files created by AIMMS are UTF8 files with a BOM at the start to mark these files as UTF8 files.There are some ways to circumvent this issue:Set the hidden AIMMS Project Setting "Default output character set” to UTF8NoBom. Use the function dex::ConvertFileToEncoding(inputFile, inputEncoding, ouputFile, outputEncoding, noBOM) to convert a file. The .json files created using dex::WriteToFile(dataFile, mappingName, pretty) are UTF8 files without a BOM.

Dear All,I have a linear programming problem (from a book of optimization in power system) with uncertain parameters as:max z = 750x1 + 1000x2subject to:x1 + x2 <= ax1 + 2x2 <= b4x1 + 3x2 <= cx1,x2 >= 0where a, b, and c are uncertain parameters with the probability function as:How to implement this optimization problem in AIMMS?Thank you.

In the realm of data handling, creating large CSV files efficiently is crucial. This article explores four distinct methods to generate a CSV file with 10 million records, comparing their performance in terms of execution time and memory increment. FmtPut Method: Time: 44 seconds Memory Increase: 1276 Mb This traditional approach uses format-based output to write data to a CSV file. While reliable, it’s not the most efficient in terms of memory usage. See FormatString PurePut Method: Time: 36 seconds Memory Increase: 2533 Mb A method that writes data directly, PurePut is faster than FmtPut but requires significantly more memory, making it less ideal for memory-constrained environments. See PUT statement DexCSV Method: Time: 16 seconds Memory Increase: 253 Mb Using the AimmsDEX repository library to write CSV stands out as a high-performance method, striking a balance between speed and memory usage, making it a suitable choice for large-scale data processing. DexParquet Me

Dear Team,I have a problem. I need some helps. I have several coils with weight. I have to load coils on wagons. There are two types of wagons. The capacity of two types of wagons are 64 and 67 respectively. I have to make rakes by joining wagons. There are three types of rakes. In one rake type, 1st type of wagon can be used. It takes 4 wagons to make a rake. In rake type 2, 2nd type of wagon can be used and 5 wagons are required to make a rake. If we club two different types of wagons, then also we can make rake. It takes 3 wagons to make a rake. My objective is to make full rakes and utilize all the coils with minimum cost.  I have designed a variable v_(i_Rake_Type,i_Wagon_Type,i_Wagon,i_Coil). The constraint is sum[(i_Wagon_Type,i_Wagon), v_WagonType(i_Rake_Type,'Wagon_1',i_Wagon)] = 4*sum[i_Wagon_Type, v_RakeTypeUsed(i_Rake_Type,'Wagon_1')];I am finding it sometimes problematic. In the last types of rakes, we need to use two different types of wagons. Am I doing in right way. Kin

I am trying to define a variable with following index domain (i, v in Vehicles_i(i),j, j1 in Nodes_J(j))I am getting a message ', )' is expected.What is the error in this definition?When I am defining as (i, v in Vehicles_i(i),j, j1)  or (i, v, j , j1 in Nodes_J(j)). It does not give any error.

Dear Team,I am facing one problem while writing a constraint. Let's say, I have three boxes with several items. Say box 1 has 4 items, box 2 has 6 items and box 3 has 9 items. I am processing the items day wise considering time as a constraint. I want that, if I am selecting a particular box, I will process all the items of that box 1st then will move to the next box. What I am getting that Day1-box1- 2 itemsDay1-box2-3 itemsDay1-box3-2 itemsDay2-box1-2 items.I do not want it. I want, choose a box on day 1, process all the 4 items based on the available time. I have written a constraint to handle it, which is like sum[d, v(d, boxnumber)] >= p_items(boxnumber) - v_Penalty(boxnumber)It means, I am trying to get the item number in a box while minimizing the penalty in the objective function.  Kindly help if I am doing anything wrong.

Wanted to share an exchange I had with a customer since it may be useful for others: ---------- question ---------Dear Aimms Support, Luis,We have the following case:In the WinUI we have some tables where we have a total row and below that the categories of that total row. For example we have the "Total days" which consists of the sum of other lines.To make it easier to distinguish between the categories and the total, we would like to add a tab/space before the categories. If I add this to the text of the identifier, the spaces will be removed in the WebUI.So my question is, is it possible to add spaces at the beginning of the identifier text? If not, what are the other options in this case?Kind regards, ---------- answer ---------Hello!Yes, you can do this.Here is an example project: Procedure pr_naming { Body: { webui::IdentifierElementText('p_test') := "test"; webui::IdentifierElementText('p_test2') := "   test2"; }}DeclarationSection __unnamed { Parame

Hi,trying to see if I can get AIMMS (running locally on my computer) to talk to one of our internal authenticated API endpoints, but running into a problem with the callback url.In the documentation, I see that the callback URL aimms will use locally is http://localhost/oauth2. However, when I run it from my own computer, I see it is actually using http://localhost:8080/oauth2.Both of these unfortunately are not on the list of approved callback urls….Since I am not the owner of the application that I trying to call, it is quite difficult for me to request a new URL to be added to the list of approved URLs. There is a local developer URL already approved and would like to make AIMMS use that particular one. The URL that is approved is http://localhost:3000/login/azure/authorized. Is there any way I can make AIMMS use this particular callback URL instead of the current hardcoded (which also is different from the documentation).

I have a stochastic optimization model wherein two-stage SP is not applicable. As such, I want to utilize sample average approximation for my solution to consider at least 100 scenarios with equal probabilities then arriving at one single solution. Is this kind of methodology default in AIMMS? Or are there things that I should do first before doing so?

Hello AIMMS Community,My team has encountered an unusual issue on an app released on AIMMS Cloud. This issue is only seen when there are multiple users accessing the application. What is the error? When two users access the application, a “Busy” status is displayed every 3-5 seconds for both users and the app is frozen. This “Busy” displays even when the users are NOT changing anything and starts as soon as the second user’s app finishes starting up. The app has no issue with a single user. Clues to causes of the error? We have narrowed down the line of code that we introduced that causes this issue. “Empty sCoreDataIssues;”. sCoreDataIssues, a set, is assigned to a CDM category. This line is within a procedure “prCoreDataCheckForIssues”. This procedure is called in a number of “UponChange” procedures (called in webui::UponChangeProcedure). Our feeling is that some parameter or set is changing continuously, the upon change is being called, and the “prCoreDataCheckForIssues”, with a non

For some demo project, I am using the secondary page actions on a page to allow the user to initiate certain actions on the current page.After I am finished with the actions, I would like for the seconary page actions to collapse again (which is also an indication for the end-user that something has happened). At the moment, after clicking on an item in the secondary page actions, the page actions stay unfolded.Is there a way that I can change the folding state of the secondary page actions from within my aimms model (most important, to close it, not so interested in opening it from aimms code)

Hi,I am trying to write a constraint with index domain on certain indicesvBinary1('1') + vBinary1('3') + vBinary1('5') = 3 * vBinary2;‘h’ is the index. Here ‘h’ is taking value {‘1’, ‘3’, ‘5’}. Do not consider it as ODD. I tried with ```index domain: | h in {"1", "3", "5"} sum[h, vBinary1(h)] = 3 * vBinary2;```It is giving errors by saying The scope of index "h" has not been specified. Help to understand it. Do not define another set for these indices only. That I know how to do it. 

Hi, is it possible to define a complex variable in AIMMS?

There is an original expression:W = xyW, x, y are all variables.Now I want to define a function which relax the product of two variables into two inequations:f(AB)={AB* >= A+cB; AB*<= dA+eB} (A,B are input variables and c,d,e are parameters)After defining the function, I want to write the primal expression to:W = f(xy).So the W can be relaxed into two inequations by AIMMS automatically.Is it possible to achive this purpose in AIMMS? Or I need to do the function manually and input the inequations on my own?

Hi Everyone, I would like raise warning if Tool tip identifier is not exists for set of parameters.   Let me know if we can check this by code.

May I know how to solve the duplicate column error since I have put the Xconstraint(i,l,g,g0) so that duplicate column does not occur? Whoever is the sender Q(i,l,g,g0) of the product cannot be the same one who is receiving the product Q(i,l,g0,g) to satisfy the local demand. May I know if there is any other way to solve this problem instead of using the constraint such as X(i,l,g,g0) + X(i,l,g0,g) <= 1 since the system does not apply this constraint at all?

I currently have a study concerning bi-objective optimization. To give context, the two objectives are to minimize total cost and to minimize the average travel distance. As of the moment, I am only a beginner in using AIMMS and I only know how to use it for single-objective problems. I just want to know if it is possible in AIMMS to do multi-objective optimization? If yes, how can I do it?

I’m currently doing an optimization model through AIMMS and I want to consider multiple scenarios for my study. Is it possible that I have considered, for example, 100 scenarios and my decision variables will only arrive at one solution that considers all scenarios?In my case, I only have one varying parameter (waste generation) in each scenario. I just want to clarify if it is possible in AIMMS and I want to know how it happens that it will arrive only at one solution. It would be a great help if you can answer my query. Thank you!

When I use the "DistributionInverseCumulative" function for beta distribution, I get the following error message from Visual C++:--Assertion failed!Program: ...Aimms\4.85.5.3-x64-VS2017\Bin\libaimms3.dllFile: c:\gitlab-runner\builds\pvap61xc\0\aimms\a...\beta.cppLine: 173Expression: istat==0--In the MainInitialization I implemented the function as follows:b_p_1 := 6;b_q_1 := 3;b_a_1 := 1;b_b_1 := 5;for n doy(n) := DistributionInverseCumulative(Beta(b_p_1,b_q_1,b_a_1,b_b_1), Uniform(0,1))endfor;For other distributions (e.g. normal distribution) the "DistributionInverseCumulative" works without any problems.I would appreciate any pointers on what I should do so that this function doesn't produce an error message?

I am trying to open a project that was originally written in version 4.37. However I have a Community License so the earliest version I can use is 4.77. I have tried opening this project in both 4.77 and 24.2 and both will crash upon opening the project with no error message.I understand the large difference in versions may be causing an issue but I have no way to test on earlier versions. Is there any way I can identify what exactly is causing this issue and could it be something other than a version issue?

To help us develop relevant data integration support we would like to ask you a few questions about your ‘BI platform’ (PowerBI, Tableau, etc and the data storage for 'feeding’ it):Do you want to visualize or analyze AIMMS data in your this BI platform? Which BI platform do you use (PowerBI, Tableau, etc.)? What data storage technology is used for ‘feeding’ your BI platform? Examples: SQL Server database, Snowflake, Databricks, file storage, etc. What mechanisms and processes are in place to retrieve data from other systems into this data platform? Is it done automatically or manually triggered? How often is data retrieved? Any quality controls in place? Etcetera.Really curious to hear from you.Thanks.