Topics about getting started or leveling up as an AIMMS developer. Datalinks, AIMMS language, building apps...
- 608 Topics
- 1,331 Replies
Thanks to extensive checking and clear reporting of incidents, end-users can often handle several incidents in AIMMS apps themselves. For other incidents, they may need to turn to the specialists in their team who know more about the data and the model. To help these experts facilitate this support, the GuardServerSession library gathers and shares information about the sessions executed by end-users.An overview of this library can be found in our new How-To on Incident Handling, created by @Chris Kuip For more on error handling, check out Chris’ course on AIMMS Academy.
I’m using CSVProvider 126.96.36.199 for writing outputs to CSV. While writing, certain rows are missing in the csv file where the variable values were 0. When checking in AIMMS (right click variable → Data) I see the domain still has that index but empty value (which means it is 0). However, while writing to CSV the index where variable values were 0 is missing. Is it possible to either include a blank row or with values 0 for the index position where the variables were 0 ?
I’m trying to define a limit to RAM memory available to solve a generated mathematical program. Is this function related to this? I tried code below, but it’s stoping my solve before the time_limit defined, before the the GAP defined and also is not using 24 GB available. And before I changed the code to use gmp functions it was taking more than 11 GB.
Hi,how is it possible to obtain a worse outcome on a more powerful PC system? Are there solver options which are benefitial for a faster PC system?In my specific case, I run a Mathematical Program (MIP) minimizing a target function. Since the computation effort is quite high, I introduce an Upper Bound to reduce the solution set. However, if I run the identical probelm instance on two systems, the more powerful one is not able to even calculate a Lower Bound. I use CPLEX 20.1. Any idea why this could be or how to configure solver options? Thanks and best regards
Hi,I want to build a model that can transport stuff from (i to j) directly or by stopping over at facility r.The transportcost (i to r) and (r to j) are cheaper than the direct transport (i to j). Problems:Open(r ) is either 0 or all possible r are opened and the amount is divided up evenlyEven if transportcosts are way lower for the extrastop r than without, the model does never choose to move all products past extrastop r. (capacities are more than enough) (goal is to minimize total cost (fixed cost and transport cost included)Related Constraints:Amount(i,r)+Amount(d,r)<=Demand(i)*OpenRecycling( r) // index (i,d,r) sum(i,Amount(i,r))+sum(d,Amount(d,r))<=Capacity(r)* Open( r) //index (r ) sum(r,Amount(i,r))+sum(r,Amount(d,r))=(Returnrate(i)*(demand(i))) //index (i,r) sum(i,Amount(i,d))<=Capacity(d)*open(d) //index(d) sum(i,Amount(i,d))=sum(r,Amount(d,r)) //index(d) Thanks for your help.I´m more than happy to post my model if that helps
Hello, for a submission I just had to download AIMMS. I have applied for the Academic License to use it. After I received the verification mail, I proceeded exactly as described in the mail. However, I still can't really use AIMMS because I always get the following error message when creating a new project. As soon as I want to open another project, I also get an error message. When I want to implement a new model I can't add new sets, parameters etc. either. Any help is highly appreciated!
Hi, I these days, I realized a new limitation with the new academic license delivery. Before, I was able to run two instances of AIMMS at the same time. However, now I can only run one instance at a time. Here are my two main uses for parallel instances of AIMMS:I am dealing with a quite heavy energy system model that runs around 2 to 20 hours (depending on the level of details). Sometimes I need to run several scenarios for a specific sensitivity analysis. It would be very useful for me if I can run the model on several computers at the same time. Sometimes I want to continue coding in AIMMS while it is running a problem. Would it be possible to run two or more instances of the model at the same time for academia?
I looked into the example of the dex:: library and I tried the DataExchange example. However I still have trouble to get started in my own program. I want to read a JSON file like given in the attachment and use the data in some variables in my AIMMS program. Could someone help me with a simple example program?
I want to write data in Excel. Generally “Spreadsheet::Assign...” commands work fine. However, I fail to include zeros in the output in Excel. I want this:i/t 1 2 1 0 0 2 5 7 I get this:i/t 1 2 2 5 7 Now I found the “axll::” library and the axll::WriteTable command, which seemed promising. Unfortunately this seems to work differently, since commands need an open workbook, which the “spreadsheet::” commands don´t. Combining both worlds doens´t work either. Can someone help? I am very confused. Thanks
Looking at screenshots can anyone tell me why the element parameter Calc(i,t) is not getting calculated? The problem comes when I am using ‘shift’ unit of measurement. If I use standard units like day or hour, the element parameter gives correct answer.I need the data of element parameter to be as follows: For example for t=2021-03-01 00:00 answer for b1: 2021-02-01 08:00 (since we are deducting 2 shifts) and for b2: 2021-02-01 00:00
Hiya! I’m completely new to AIMMS so apologies if this is a really fundamental thing to ask. I’ve been working on a model that I would like to call from within Python using AimmsCmd - for now while I’m just trying to get it to work, my code in Python linking to AIMMS is pretty much identical to the script in the guide to running batch commands:aimmsPath = "C:\\Users\\44750\\AppData\\Local\\AIMMS\\IFA\\Aimms\\188.8.131.52-x64-VS2017\\Bin\\AimmsCmd.exe"command = aimmsPath + " solver.aimms < cmds.txt > log.txt"solve = subprocess.call(command, shell=True)log = open("log.txt","r")print(log.read())log.close()When I execute it however, I get this error:Error: Unable to open AIMMS with "--as-server --ignore-dialogs --hidden "solver.aimms"": Starting up Aimms failed. Program initialization error.Thinking it was probably my model or my code that was flagging up the error, I downloaded the StandAlone example from that same guide and copypasted the Python script - but it returned the exact same
I am trying to open the model that gives the demo of how to connect AIMMS with Python in AIMMS Developer, however I am getting an error and I am not able to open the model. The model given at the below link:https://how-to.aimms.com/Articles/487/487-aimms-with-python.html
The goal of this series is to cover some essential concepts and best practices for app documentation. Check out Part I here. Get to know your audience You probably got the key facts about your users' needs and abilities when you started your project. Don’t forget these needs and abilities when you write your documentation! You’ll need to consider things like: what terms are they familiar with? what assumptions can I make about their knowledge? what do they really need to know? (hint: not your entire thought process when you made it, but how they should use it) how often will they use this app? which features will they use most frequently? Are different users using it in different ways? (hint: identify clearly which parts are useful to which users) Level up your writing skills It may (or may not) sound easy to write documentation, but in fact it takes training and practice for most people to write technical documents that are both useful and usable. One way to build this skill is
I have large a planning problem in AIMMS, which is linear optimization. I am using GUROBI 9.0 for solving it and the solver is set to use the Barrier method based on our experience that Barrier converges faster than Simplex in our large-scale problem. After around 56 hours, the program stopped and I got the “Warning: Model status 13: Error no solution, solver status 1: Normal Completion”.Here are screenshots from the warning and progress panels of AIMMS. Error/Warnings PanelProgress PanelNone of the existing questions and discussions on “Warning: Model status 13” are related to the case that it says “Solver status 1: Normal Completion”. I could not find any more information on software or the AIMMS manual regarding this issue. I need to find what is the source of this problem. I would be grateful if you can help me with this issue.Thanks,
Already have an account? Login
Please use your business or academic e-mail address to register
Login to the community
No account yet? Create an account
Enter your username or e-mail address. We'll send you an e-mail with instructions to reset your password.