Optimization Tooling

Hi, There are some changes I did on the setting before I run my MIP project in AIMMS. I wish to know what they mean and how they work. Can anyone explain it to me? 1. I change the ‘aggregrator’ to 0. 2. I change the ‘global thread limit’ to 1. Thank you in advance.

Hi dear community, I have a general question regarding the subtour elimination method of DFJ vs MTZ. The “CVRP” example on AIMMS website uses both methods to elinimate subtour and the result shows MTZ is faster than DFJ. However in the example, the MTZ is run together with the model while the DFJ is only used in the callback. So my question is, do we always run MTZ together with the model or it will actually give a better computation time if we use MTZ in callback just like DFJ? And actually in my current project, I’m trying to get a storage assignment solution (400 items to 400 locations) with the minimum total travel distance for the pickers picking multiple batches. Each batch will include at most 5 items. So for this problem, say if we have 1000 batches, it will be 1000 TSP problems among at most 5 locations. So in this case, will there be any huge difference for me to use DFJ vs MTZ since the n is actually relatively small in each batch?  Thanks in advance!

hi all,sorry for the trivial question but was trying to figure out:how to force aimms to show “0” values for parameters and variables/results and correspondingly exporting those parameters to excel with “0”at the moment, whenever the parameter or variable has “0” is appears as empty line/cell.any hints on these two questions much appreciated!thanksnick

Hello,I am trying to print a custom message at the command-line, while running aimms via a batch-file. The goal is to get an information about the status and the progress of the optimization. I have tried the DialogMessage, DialogProgress and the Display function with no success. Can anyone help me with that?Best regardsJonathan 

Dear all, In the accompanied model, I try to decrease the inter-facility transport flows between warehouses by changing the production allocation per factory. However, when I try to solve this model, after +- 20 seconds the solution comes back at '0', and I can see that nothing has changed. Could anyone point out to me why this is happening? Kind regards,

Dear all, I want to find the point on the pareto front (obtained with the epsilon constraint method) that has the minimum distance from the utopia point. How can I do this in aimms? Thanks Best Grazia

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 staff,I would like to receive your help with linearizing the following constraint. Given the indexes i, j, c, a I have the following variables and parameters: x (i,j,a) continuous variabley (i,j,a) continuous variableR (i,j,c,a) binary variableA (i,j) parameterB (c) parameter The constraint that I need to write is the following: y(i,j,a) = (x(i,j,a) / A(i,j)) * (1 - sum((c,a1)|ord(a1) <= ord(a), R(i,j,c,a1))) + sum((c,a1)|ord(a1) <= ord(a), (x(i,j,a) / B(c)) * R(i,j,c,a1)) forall i, j, a I am struggling in particular with the linearization of the second part:sum((c,a1)|ord(a1) <= ord(a), (x(i,j,a) / B(c)) * R(i,j,c,a1)) Please note that there are already other constraints imposing that sum((c,a), R(i,j,c,a)) <= 1 forall i, j, therefore the summation of sum((c,a1)|ord(a1) <= ord(a), R(i,j,c,a1)) is always either 0 or 1. Thank you,Kind regards, 

I am having trouble to find where to set my parameter as Read Only. The most similar from the WinUI Pivot Table functionality was to make my parameter defined then, the user can't change its data inside WebUI. Is there any other way?

I've just about got a handle on the css "rules" for the widgets, but the buttons for the new dialog pages don't follow those rules, it seems. I've tried a gazillon permutations of .dialog-open .dialog-page-container .ui-dialog-buttonpane .ui-dialog-buttonset button:last-child button .ui-button .action-cancel .ui-widget .ui-state-default .ui-corner-all .ui-button-text-only How can I change the button color, text color, etc? At this point the only thing that changes anything is code:.theme-mytheme.dialog-open .ui-button-text and that only changes the background around the text itself, not the button background. Thanks!

Hi everyone,I have been trying to call an AIMMS (academic license) procedure from python although this doesn't seem to work. I got the following code from another thread, which seems to work with a paid license. I also saw on another post that the academic licence might have some limitations in this regard. Is there an API in another language, were I can make Python wrapper around this other language?orIs it possible that AIMMS internally allows to run scripts in some language, in which case a script can be built  in such a way that they exchange model parameters/inputs/results with the outside world? Best regards,

Frequently we run into the limitations of resizing widget. Here is one concrete example which could be solved if we can hide the table header.   In our application we have a table with a 1-dimensional parameter with 4 items. With a table widget of row height 1, we don't see the last item unless we scroll. With a table widget of row height 2, we have a lot of redundant white space we want to use for something else. All items would be visible in the smaller widget, if we could hide /collapse the header. Is there is a way we can remove the column headers via CSS?   As a side note, I believe grid we are limited to when placing widgets is too coarse.

HI everyone, so I have to model a problem but when I run the procedure, it tells me: Warning: CPLEX: Q matrix is not positive semi-definite.Warning: Model status 13: Error no solution, Solver status 9: Error: Setup failure (see message window).I have no idea where my mistakes are, that's why I come to ask for your help.so here is my problem :I have 4 variables, X(j,i) and Q(i,l) are non negative and Y(i) and E(i) are binary variablesMy function to minimize is : sum( (j,i), csb(j,i)*X(j,i) ) + sum( (i,l), cbd(i,l)*Q(i,l) ) + sum( i, ce(i)*E(i) ) + sum( i, co(i)*Y(i) )My constraints are: sum(i, X(j,i)*Y(i)) <= capmp(j)sum(l, Q(i,l)) <= capb(i) + 50*E(i)sum(i, Q(i,l)) >= ed(l)8.333*(sum(j, X(j|j="Afyon",i))+sum(j, X(j|j="Konya",i))) + 9.091*sum(j, X(j| j="Import",i)) = sum(l, Q(i,l))sum(i, Y(i|i="Istanbul")) =1sum(i, Y(i|i="Ankara")) =1sum(i, Y(i|i="Izmir")) + sum(i, Y(i|i="Sakarya")) + sum(i, Y(i|i="Adana")) =1sum(i, E(i|i="Izmir")) + sum(i, E(i|i="Sakarya")) + sum(i, E(i|i="Ada

I am currently working on a vehicle routing problem and get this error when i try to run it. Does anyone know how to fix it.  I have also attached the excel file where the data is stored. (Ignore the emission zones column)   Kind regards Prakash

Dear All, Is possible to retrieve MIP optimalilty gap and Solving Time for each solve in to a parameter? If so, how to do this? Thank you very much.

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?

When querying data from a SQL Server using an ODBC driver (using SQLCreateConnectionString() and ‘trusted_connection=yes’ for the AdditionalConnectionParameters argument), is the authentication carried out for the service account running the AIMMS PRO service on the server or for the user logged into the PRO portal on an AD-linked environment? Is there additional setup required for double-hopping? Or does it depend on whether the AIMMS PRO service account is registered on AD?   I am looking for support to build solutions where the database serving the AIMMS application is restricted for use by specific individuals and not service accounts.

Hello 1- I will try different constraints for my model. For example, I want to disable all constraints and show the results. I tried to created parameters as a below; parameter: IsDisable , range=integer Constraint: MyConstraint , index: (i,j) | not IsDisable But in index section in MyConstraint: " t | t>=2 " I could not add the " | not IsDisable " 2- Also How can I write the solution to excel? Could you please help me? Best Regards.

Hi all, I am constructing an app that a lot of users are using, with a lot of different datasets. These datasets are loaded from and saved to a database. Is there a possibility to show a name on every page in the app specific for that dataset, without having to add a widget to every page? I provided a screenshot below of a page in the app. I was thinking about maybe the word "Menu" that could be editable? Or could I place something before "Masterdata" that shows which dataset someone is using. As people only go to the homepage to change datasets, this would seem logical to me (this page would then display "Dataset 1> Masterdata", or something like that). Or does anyone have a better tip for this?

Can anybody suggest how can i eliminate the following error? Warning: After 66905692 iterations CPLEX 12.8 terminated and leastcost is still infeasible. 

Hi dear community,   I have a constraint as sum((k,z1), y(b,k,z1,l,z2)) <= 1 and I want to add if statement to it: if k = l, then z1 cannot be equal to z2; if k<>l, then there’s no further constraint for z1 and z2. I tryed to add it like this: if k<>l then sum((k,z1), y(b,k,z1,l,z2)) <= 1 endif; if k=l then sum((k,z1)|z1<>z2, y(b,k,z1,l,z2)) <= 1 endif; The AIMMS through out the message “The scope of index "k" has not been specified.” like shown in the screenshot(I’ve highlighted where the error is-the first k appears in if statement). So my question is, is there a way to fix this constraint in the way that I want it to be? (maybe using element parameter)?   Thanks in advance!

Hello everyone, CPLEX returns optimal solution for small instances of a MIP model. But when try to solve a larger instance, CPLEX return a local optimum (solution checked by a heuristic). The model is MIP with a number of Big-M formulations that are replaced by Indicator Constraints. For one of the large instances:  # of constraints: 2086337 #of variables: 1122331 (66225 int)  #of none zero: 7223176 It takes 53557 seconds for CPLEX to close the optimality Gap. Any idea? please share your thought.

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,