AIMMS Language

Model descriptionWe have a non-linear mathematical model with the following set, variables, and parameters: Set t in [1,N_T]     Variables x_t y   Parameters A B C_t  And the following objective function:min{sum((x_t-A)/A) for all t}Subject to:x_t = x_{t-1} + B(Ay - x_{t-1}y - C_{t-1})

Dear All, I want to generate an integer parameter based on the combination of a number of component as shown as:   K1 K2 K3 C1 1 1 1 C2 1 1 0 C3 1 0 1 C4 1 0 0 C5 0 1 1 C6 0 1 0 C7 0 0 1 C8 0 0 0   where K1 … Kn is the number of component and C1 .. Cn is generated combination based on component number. The value of 1 means that the component is available and the value of 0 is otherwise. Is it possible to do this in AIMMS? Thank you very much.

Hi, Is there any way of looping through a for-loop backwards? The subset is ordered by user, for example {1,4,3,5}. I want to loop backwards so from 5 to 3 to 4 to 1.   

This article discusses some elements from the popular software methodology Test Driven Development in relation to the AIMMS Library AIMMSUnitTest. Gather requirements from stakeholders What are small examples? What are the edge cases, including error cases, performance? Implement requirements as unit tests and see them fail! Development Write the code for the functions Execute tests and see them pass! Refactor until performance is acceptable. Repeat Read more...

Hi all, I am modelling production routes per production order in which the production routes provide the sequence of the jobs to follow. I created a subset ProductionRoute(i) that is a subset of all possible jobs. See below a production order i that follows the sequence: SMD → AOI → REW. When implementing this in the subset and when running the model, it will follow the sequence AOI → REW → SMD since operations is stated ascending. Such as below.   Is there a possibility to model in AIMMS that it should follow the production route as stated  in the first figure? Instead of looking to the ascending order of the subset. 

Hey everyone, I´m currently using Aimms to build a model for my Bachelor Thesis. I have never worked with Aimms before so I´m pretty clueless in some regard.   So my problem is the following constraint: sum [i, aSP(h,i)*x(i,t)] + sum [j, sum [m, aFP(h,m)*(y(j,m,t))]] <= Capacity(h)   Here x(i,t) and y(j,m,t) are the decision variables which represent the accepted requests for two Product types. i are the different types of Product x and j are different types for Product y. t stands for different Periods. aSP and aFP indicate if product x(i) or y(j) needs Ressource h for its production. I have declared Capacity(h) as a parameter with values for each h. My Problem is now that the Programm takes these values for each seperate period, but the capacity in period 2 is of course lower than the capacity in period 1 and so on. I also cant just declare Capacity parameters for each period, because the remaining capacity in the periods

 Good morning all,Please, can someone tell me why I keep getting this error ? Both SOC(agg,t) and P_Charging(agg,t) are variables.Thanks so much.  

Dear community,I just rolled into AIMMS, so the application is very new to me.I came across a problem with implementing constraints into my model. You can see the specific constraint and my model in the attached illustrations. After filling in the definition for the constraint, an error popped up, saying "The scope of index "cred" has not been specified.", where "cred" is the index domain for the variable "CarbonCredits".I already tried to re-implement the whole model, change the index and i messed around with different brackets in different positions. Nonetheless, i kept getting the same error.I would appreciate it if someone could help me out. A picture (of an example) on how the definition of this constraint should look like would be phenomenal as well.Thanks in advance, Stijn

Hello everyone the following constraint       0<= P_cotw <= sum PMAX_c 'tau' w 'tau<=t How can I declare the right side of the restriction   c, o, t, w subscripts. 'tau' t = {1,2}   My case is: Constraint LimProdCan {     IndexDomain: (c,o,t,s);     Definition: PotGenCan(c,o,t,s)<=CapConstruir(c,t,s); }   Thank you

Hi everyone, I need to make a simulation in Aimms to simulate the mechanism on the following picture:   Order Release Mechanism I have no problem in declaring all the sets and parameters, but my main 2 problems are too make the periods pass correctly and repeat all processes in the periods and too update the loads and sets at the right points in time.  I have too do this via simulation so without an objective function thats also something that throws me off cause i cant use a Mathematical Programm so solve this.  Maybe the solution is simple but i havent ever worked with Aimms and that is a very big project for me, which is also very urgent so i really appreciate any help i can get.  With kind regards AlexPS.: The programm i made so fa

Hi! I’m doing a supply chain optimization using AIMMS for my master project and I have a problem with my binary determinant variable as well as the result error computed. Since this is my first time using AIMMS, I am not sure on how to debug it.The constraint of my binary is X(i,l,g,g2) + X(i,l,g2,g) ; where g≠g2.After I run the program, it saysWarning: The rows "TransportationBinary(liquid hydrogen,truck,g1,g3)" and "TransportationBinary(liquid hydrogen,truck,g3,g1)" are equal in the generated mathematical program "MinimizeDailyCost".  This may lead to non-unique shadow prices.  For more information regarding potential causes and consequences, see the help associated with the option "Warning_duplicate_row". Can anyone help me explain what is the problem? I am also confuse on which section to declare the g≠g2 in the transportation constraint (g represents the grid squares/ supply demand location).Appreciate your help!

Hi, I have been following the Employee Training example. However, I cannot run the code (attached). It is said that the solution does not exist. I don’t know what causes it.Furthermore, how do I check and know if the equations are not feasible ya? I’ve been looking into this Math Inspector, but somehow it’s difficult to understand for me. Thanks,  

Dear all, I want to write a code in the MainExecution section. I want to consider in the first cycle a constraint, but I wan't to consider this constraint in the second cycle. How can I write this? Thanks Best GL

I'm liking the group widget in WebUI, but I'd sure like to put more than a few buttons across it. I want to have a row of buttons all the way across the top of the page, and the only way I can get the buttons to not be 2 columns wide each is to use a group. But the group cuts off any buttons that exceed about 4 columns wide! How can I get either more buttons in a group all in a row or smaller buttons that I can place individually? Thanks!

Hello everyone,I am trying to implement a supply and demand model in AIMMS. This is the first time using it for me and I'm having some issues. The case is as follows: There are Printer companies that supply books to Retailers. These Printers can send the books directly to retailers, or through crossdocks to be consolidated. I have modelled the set of Printers with index P, the set of Crossdocks with index C and the set of retailers with index R. The case asks for a set of locations as the union of these three sets L = P ∪  C ∪ R. I am not sure how to model this union of sets and can't seem to find any info on this. Does anyone know how to do this?Not sure if it matters, but the amount of Printers, Crossdocks and Retailers should be variable and dependent on an Excel input file. Thanks!

Hi, I have a question regarding some best practices in terms of reading excel files with the axll library. Here, we have to specify the header / dataranges before reading. Often, we don't know exactly how many rows of data we have. We can of course set the max row number arbitrary large (or to the excel sheet row limit of 1,048,576), but that feels like a ‘dirty’ solution. Is there another way we can only read the rows which actually have data? Ideally, I would like some sort of functionality which ‘peeks’ into the file and tells us where the data is. Curious to hear possibilities in this regard. Thanks!

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 ad

Dear all, I have a matrix T(i,j,k,s).I want that for each s, i and j are equal.How can I do this?Best

Is there an extension or language config so I can view my AIMMS Text Representation with syntax highlighting in VS Code? It would be super helpful. I think I can create one, but if someone's already invented that wheel, no sense in re-inventing it. Thanks, y'all! ~Bon

I would like to report the contents of the Progress window such as the number of variables, parameters, non-zeros, objective function, solve-time, used method, etc. to a customized log file in a preferably .txt or .xlsx file formats. My goal is to have separate log files for each run so I can analyze specific parameters,  e.g. the relation between objective function, solver method, and solving time.  I already found a way, in which the solver (I use Gurobi) writes this information together with a specific number of solving iterations to a log file in the log folder. This method has two major drawbacks for me: First, with every run, the new log will be added to the older log in the same .txt file. So I have to exit the AIMMS after each run to have separate log files! Second, there is a lot of information in this log file that I have no interest in. So I need to write an algorithm in a third-party application to fish the needed values.   Are y

Hi, I was trying to play around with Monte Carlo simulation in AIMMS. I can save the results from MP.Objective for every run. But, how can I save the solution for every run? I tried to use something like below for every run:Variable_Result(run, param1, param2) := Variable(param1,param2);It’s in the procedure “RunMonteCarlo” in the attached file. But, it doesn’t work. Any idea?Thanks,Zulfan

Dear all, I must to set the non anticipativity constraints in aimms for the stochastic problem.Then for s scenarios and x decision variable I must to write thatx1=x2=x3=..xsHow can I write this in aimms?Thanks 

Dear All,I have a question on how to limit the range of an index and since I’m new to Aimms I can’t find a proper solution. I just want to limit certain indices to a certain range for a specific constraint.First example (Constraint):Index Domain:tDefinition: e(t) <= e(t-1) |t<Tmax |t>TminError Message:In an inclusion only the middle term is allowed to contain variables, however in the inclusion e(t) <= e(t-1) $ t < Tmax $ t the left term contains variables. Second Example (Constraint):Index Domain: (i,j,k,t)Definition: r(i,j,k,t) <= o(i,k-1,t-1)*RM(i,j) |k>1|t>1Error Message: The operators <= and > should to be the same for numerical inclusion (or use parenthesis). As I’m new to aimms I dont seem to understand the principles properly. May someone point me to the right way to do this?Thank you very much in advance!Best RegardsJonas 

Dear All, I have been trying to use ellipsoid uncertainty in a simple problem that I have.The problem is an assortment optimization. Then, I have the Demand Mean for each products Dem(p) and the Covariance matrix or the variance Var(p,p1) for each par of products. The objective is to select the products what will maximize the expected demand Dem(p) at the same time, penalizes products with high variance. The uncertainty set will be a ellipsoid uncertainty. I would like to create the eelipsoid uncertainty using the uncertainty region like:Demand(p).level - sum[p1 , Var(p,p1) * …………There is a example in the book on page 341. but it’s not clear for me.  Could you help me to model the ellipsoid uncertainty using the uncertainty property? Thank you 

When you solve a Mathematical Program in AIMMS, the default behavior is that AIMMS will let the solver solve the problem to (local) optimality. There might be situations where you want to stop the solve procedure after a set time period, or once a solution within a given percentage of the best value is available. This article will show you how to apply different stop criteria to a 'solve' statement in AIMMS. Read More...