Solved

I am trying to solve an MIP model with AIMMS. I run the AIMMS for a specific parameters and obtained the optimal solution; I also solved the model with same data/parameters using a heuristic to test the optimal solution- it is indeed the optimal. Now I first change the parameters (i.e., using different values) and save the changes in a new "case" using "save case as" option under different name. Then I set the new case as the "active case" and try the model with the new data. surprisingly AIMMS returns the (same) optimal solution obtained with original "case". I used to use the "single file data management" so I thought this might be the reason. I changed this to "disk files and folders" by going to Menu File > Open > Data file>convert...but it didn't help at all. I also noticed that when I load a case, the model's decision variables contains some values from perhaps previous runs; not sure if this is normal with AIMMS. Any help on this is greatly appreciated in advance. Thank

Hello, my model has the following constraint: s(i,j)*x(j)+sum((m,t_), MW(i,j,m,t_)*y(j,m,t_))+sum((k,t_),MWK(i,j,k,t_))+dM(i,j,t)-dP(i,j,t)=B(i,t) The index domain is: (i,j,t) I want the system to accumulate all MWK(i,j,k,t_) respectively all MW(i,j,m,t_)*y(j,m,t_) from t_0 until t_=t and then to add this solution to s(i,j)*x(j). Because t (periods) is already in the index domain I defined a second index t_ in the period set. Unfortunately the system sums up all MWK(i,j,k,t_) over all periods and add this in every t. So if there is a MWK(1,1,1,5)=1 then the system adds this also in t=0. Is there any possibility to determine that the sum should start at t_=0 and end in t_=t? Thanks in advance!

As we are converting an app to the new theme and want to make use of all the new features, I would like to get rid of (close to) all buttons on the page. But on almost every page we have a 'help' link to an external website, where a lot of reference materials can be found. For this we used the 'ExternalLink' option of the button. Is something similar possible in a page (or widget) action? For instance, I can't find a way to redirect to a url in a procedure.

Hi All, I want to create a user interface or page where i can control some of the constraints to toggle and run the model. e.g. Lets say we have 10 set of constraints and I want to run the model with 8 currently while rest 2 I want to disable for the run. This needs to be dynamic Is there any documentation available for the same or any example. Regards Ankit Bhagat

I would like to implement a modified monthly calendar, where rather than each month being a strict calendar month, I use the 4 week, 4 week, 5 week pattern. Has anyone used this previously, and if so do have any tips to share? Thanks Rachel

I have a model that describes the optimal relocations of stock in a situation where the total inventory is sometimes larger than the in-house warehouse capacity. I defined the set 'products' and 'flows' with indices (respectively) i and j. The decision variable(Xij) is the (integer) amount of products to assign to each flow, minimizing the cost involved. I am currently struggling with implementing one of the constraints: for each i in flow j=3, the value of Xi3 should be some integer (say 0 to 10) times the flowcapacity (=45). After some searching on this forum, I figured I should try adding a parameter Flowcapacity(j), make Flowcapacity(3)=45 and all other Flowcapacity(j=/=3)=0. Then, in the constraint, include an if statement: "if Flowcapacity(j)>0 then X(ij)=Flowcapacity(j)*{0,1,2,3,4,5,6,7,8,9,10}". The program seems to accept the reference to the parameter, but not the subset of integers (which was a long shot). How should I formulate this constraint?

Hi, I am using AIMMS for my bachelorthesis. How can I delete a project from "projects"? Thankyou

In our app we use excel upload and downloads such that users are able to change and distribute data more easily. So we have written procedures that write and read excel files for the data in the app. With the new widget actions, it seems most logical to also place these download and upload actions there. But there is still an option to download the data as a .csv file. As not to confuse any users which download they should use, I would like to disable the option of downloading as a .csv file for certain tables. Is there a way to disable this feature?

I have following unit consistency warning for the expression below: {i| sum((p,yr),TLin(i,p,yr)) <> 0} Warning: The units associated with the expression (sum( ( p, yr ) , TLin(i,p,yr) ) )[m3], and with the expression (0)[] are not commensurate. Is there a trick to get around this? I know I can define a parameter with a value 0 and unit m3, but do not want add modelling complexity for such a minor issue. Any suggestions are welcome. With kind regards, Binod

Hello! I have 5 MPs, three of them running in for cycle, so somehow I want to track which MP is solved in a particular time. 🕖 I imagined that, I make five label, with the name of the MPs, and for those string parameter I make annotation, which defines the mp's status (running, finished). Can I make annotation for non indexed parameters? The css code I use is the following (maybe that here misses something 🤔, without the annotation it's working 😅) .tag-widget[data-widget\.uri="OptimizationLog_lbl_SMG1"] .annotation-Active{ border-radius: 5px; background: rgb(17, 255, 125); border-style: solid; border-width: 5px; border-color: rgb(17, 255, 125); color: #fff; } Thanks for your help!

I'm not able to start any PRO session anymore, keep getting this error "Cannot verify project validity" and it says to check logs. The error message in the server log is: java.io.IOException: C:\Program Files\AimmsPRO 2.0\AimmsPROLibrary\vc141\x64 doesn't exist. What could be wrong?

Hi Community, i have to build a robust optimization model for my masterthesis at the Technical University in Braunschweig. Therefore i choose the Minimax-Regret Function! These approach deals with different scenarios k. I need to implement this function in an existing basic model, which is a single factory location problem. The basic model calculates the minimal sum of all deviations "d" from target values (so it is a Goal Programming approach) and based on these deviations the output of the model is one compromise-optimal location solution (the basic model is based on one scenario). So first i implement a new index k for the scenarios to dealwith more than one scenario. How to deal with a minimax-obejctive function in AIMMS is already explained very well in one of the AIMMS Modeling Guides (https://download.aimms.com/aimms/download/manuals/AIMMS3OM_LinearProgrammingTricks.pdf). But i have some issues with the Regret. The definition of the regret is R = d - d*. Therefore, d is the de

Is it possible to disconnect automatically users in AIMMS PRO after being inactive after some minutes?

Dear, In the attached model, you should only run the procedure ReadFromExcel. This should load all the relevant sets and parameters. When I try to solve this model, I encounter different memory errors. I either see: Memory allocation error Memory allocation error: while assigning "xxx" bytes Are there any steps that I could take with regards to the index domain of some parameters, constraints or variables, such that this model becomes solvable? I think there are no other errors in my model, but would also like to double check this. Kind regards, Koen

Dear Ladies and Gentleman, I use the solver Baron for a NLP and solve several problems with an if function in the Main Execution. After a specific time limit is exceeded, I want to save the Upper and Lower Bounds in a file or even better in a Parameter. Is this possible? Best regards, Jacqueline Wand

Dear all, I have a few questions about my model, which I hope the AIMMS community can answer. Please bear with me, as I should be drawing to the conclusion of my thesis (when this model works). Sum and indices In the accompanied model, I am trying to add several constraints. However, when setting these constraints I often encounter errors like "the index (p) does not denote a subset of the domain of set "FactoryLines"" for instance. I often find that I make mistakes with the indices in the constraint itself and within the constraint definition. I have tried looking at the guides online, but with no effect. Could anyone explain to me (preferably in layman's terms) how the indices in constraints work as well as indices within a sum argument? I am encountering similar problems with the parameters "IncomingStock" and "OutgoingStock" Stock balancing One of the decision variables, StockAtWarehouse is made from the following definition: StockAtWarehouse(p,w,t-1) + sum(p, IncomingStock

Is it possible to select not only one but more tasks on the WEBUI Gantt-chart? I couldn't find any description about that. Does somebody have any infos about that? Thanks, Zsófi

Dear staff, I need your help with an objective function where I have the product of two variables. I have the following variables and parameters: y(i,j,c,a) binary variable x(a) continuous variable P(c) parameter How can I linearise the following objective function: MIN: sum((i,j,c,a), P(c) * y(i,j,c,a) - P(c) * y(i,j,c,a) * x(a)) Thank you

Hi, The CSV Export DLL does seem to export 0-dim identifiers. Therefore I would like to use put. However I can't figure out how to obtain the value of that 0-dim variable. I have the next snippet of code, which works fine, but the value of the variable is still missing. code:for (IndexVariables) do if (IdentifierDimension(IndexVariables)) then !do something else else csv_alt_name := FolderName + IndexVariables + ".csv"; put csv_alt; put IndexVariables + "\n"; put name_of_some_variable; putclose; endif;endfor; The line "put name_of_some_variable;" prints the value of a variable. But it should of course print the value referred to by IndexVariables. How to do that?

The WinUI has a super obvious tab for the Legend of a linechart. But there seems to be NO way whatsoever to display the legend (or anything that will work as a legend) on a WebUI linechart. I even tried the (seemingly obvious) solution of using a legend widget. If this will work, I can't figure out how. Is there a way to show the legend? And if you don't have on yet, is there a workaround and do you have it in the plans in the future?

Dear Staff, I need help writing the following constraint using the AIMMS language. I have two indexes: c a Where "a" indicates years. I have a variable y(c,a) I would like to define a summation over "c" and over "a" as less than or equal to a value. But the summation over "a" should be done only from the first year until the current year. I am trying this formulation but something is wrong with it: sum((c, a1|(a1="A01") and (a1=ord(a))), y(c,a1)) <= Value Can you please help me writing this correctly using the AIMMS syntax? Thank you,

I tried to set my Gantt-chart to readonly, such that users would not be able to move any tasks on the Gantt-chart. Unfortunately I cannot find neither this option in WebUI nor in any AIMMS Manual. Could you help me to set it up? Thanks !

Hi, is there a similar code that I can use if a project has set the option Data Management style to Disk files and folders? The below code was valid for projects using option Single Data Manager file. The code was available from https://techblog.aimms.com/2012/06/05/save-a-case-from-aimms-procedure/ (note this is blog is now not available) ************ !First try to find a case with the name indicated by CaseName. If AIMMS !can find this, it will store a reference to this case in the element !parameter CaseReference if ( not CaseFind( CaseName, CaseReference ) ) then !If no case with the name indicated by CaseName could be found, then !we try to create a case with this name. After creating the case, AIMMS !will store a reference in the CaseReference element parameter to the !newly created case if ( not CaseCreate( CaseName, CaseReference ) ) then !If there was an error while creating the case, notify the developer !by raising an error. If the raised error is not cau

Hi, When I run AIMMS, I’ve got this result in the progress window as shown in the picture attached, I wish to know what they are mean and how they work. Can anyone explain it to me? 1. infeasible 2. integer infeasible 3. intermediate infeasible 4. terminated by the solver 5. solution does not exist 6. solver not called 7. left 8. nodes 9. thread 10. nonzeroes 11. variables Thank you in advance.

Hi, I have an integer set, a parameter with filenames, and a parameters with Aimms'standard date/time. How do I select the newest file, or how to sort a parameter and select the first, or how to select the smallest, largest? Thanks!