AIMMS Developer

Topics about getting started or leveling up as an AIMMS developer. Datalinks, AIMMS language, building apps...

  • 578 Topics
  • 1,259 Replies

578 Topics

C
ChunyangEnthusiast
asked in AIMMS Developer

How to include a variable with different domain in equation

The variable X is with the index domain i, while the variable Y is with the index domain j. The number of element in j is twice that of i, which means J = 2*I when seeing these two index as number.Now I want to write a constraint:X(i) <= Y(2*i)How can I do this in AIMMS? 

1
gabiservidone
AIMMSian
1 day ago
M
MZwanenburg
asked in AIMMS Developer

Summation over index domain

Hi, I am trying to model the following constraint:with x as a nonnegative value indication the hours processed of job j-1 in time bucket t and Y as binary variable indicating that job j in time bucket t may start or not. The problem is that t is in the index domain and I need a summation over t’ based on t. How can I properly model this? I already have two indices for the set time buckets: t and h. But how do I model that x(i,j,t) is the same as x(i,j,h)? Preferably in one variable if that is possible? If I just simply say x(i,j,h) in the constraint I get the error: The parentheses in variable "x" do not match. Which is true since I modelled the variable as x(i,j,t).  

1
M
5 days ago
N
Noob9000Enthusiast
asked in AIMMS Developer

Export Set on Separate Tabs using AXLL

Hello - I'm creating a script to export a bunch of vars/params to Excel/CSV. It needs be pretty clean/standardized so it can be read into a UI.I tried:write AllVariables to file export_file;But the output was too messy.  - Is there a way to silence Basic/NonBasic? - My output is often Nodes x Time, which AIMMS seems to prefer as (n,t), but then it shows Time as columns instead of rows (which is SUPER ugly in the text file). So I have to duplicate everything as parameters with (t,n) for the export. Or am I wrong? So now I'm looking at using AXLL, but it's pretty tedious.This is what I'm currently doing:axll::CreateSheet("VarName1");axll::WriteTable(Var1, "A2:A5", "B1:AZ1", "", 1, 1);axll::CreateSheet("VarName2");axll::WriteTable(Var2, "A2:A5", "B1:AZ1", "", 1, 1);… ad nauseam There has to be a better way. Is there something like:for i in MySet do   axll::CreateSheet(FormatString(“%e”, i));   axll::WriteTable(i, “A2:A5”, “B1:AZ1”, "”, 1, 1);endfor; I want to print one variable per tab in

2
gabiservidone
AIMMSian
1 day ago
RoxannaBindenga
AIMMSian
RoxannaBindengaAIMMSian
published in AIMMS Developer

Friday Demo Impressions (May 12, 2023)

On Friday, May 12th, we had our internal Demo & Feedback session. The following topics were discussed: WebUI: enhancement in collapsing parent tasksPreviously, it was not possible to collapse the parent if one of its child steps was active: Based on users’ feedback this has now changed. It is possible to collapse the parent, and a blue line will indicate that one of its children is still active, hovering over it showing the name of the active step: New function: webui::RefreshAllWidgetsBy default, the AIMMS UI will only update after a procedure has fully run. However, sometimes you want to inform the user in between; a function for which, in WinnUI, PageRefreshAll was introduced. This function however didn’t work for WebUI. For the same purpose @Koos Heerink now introduced the new function webui::RefreshAllWidgets:You can use this function in combination with webui::UseTransparantVeil to make the ‘overlay’ on the page transparent for as long as the procedure is running (but bear in

320
RoxannaBindenga
AIMMSian
7 days ago
L
lksqwertzExplorer
asked in AIMMS Developer

Initial condition

Hi all,I am relatively new to AIMMS and have a problem with the initial condition.I have a variable Y_jkt which is the number of machines of type 𝑗 needed in each shift to satisfy thedemand in period 𝑡 with 𝑘 work shifts.  the initial condition is:∑k∈K k(Yjk0)=Aj/ ̄Oj ∀ j (8)So my question is how do I program this since t just takes the value 0?

0
L
13 days ago
H
HazirahEnthusiast
asked in AIMMS Developer

Integer Solution to Minimize Daily Cost does not exist

Hi! I’m working on my small project and I’m a beginner in programming and AIMMS. I tried to run the model that I have developed but it resulted into “Warning: After zero iterations CPLEX 22.1 concluded that an integer solution to MinimizeDailyCost does not exist.” I attach my model and data.I’m not sure where to start rectify this problem. Appreciate if anyone can help.

2
Marcel Hunting
AIMMSian
11 days ago
C
ChunyangEnthusiast
asked in AIMMS Developer

How to calculate variance of a time series variable efficiently in AIMMS?

There is a time series variable A={a1,a2,a3...at}, and I want to constraint the fluctuation of the variable. I did this in AIMMS with the following way:1) I define a variable series_mean to calculate the mean of the series, 2) I define a constraint to make the variance of the series be no larger than 10000.   series_mean = sum(t,A(t))/T;sum(t,(A(t)-series_mean)^2)/T<=10000; However, this seems burden the computation and the solving time soars even though the constraint didn’t work in optimization. Like in one scenario, with or without the constraint I get the same result, however the solving time with the constraint is 10 times that in the case without this constraint. (The constraint is a must though) .So I hope to know is there a better way to do the same things in AIMMS?Thanks.

2
C
15 days ago
K
kin006Explorer
asked in AIMMS Developer

Error when solving non-linear model with AIMMS Outer Approximation Algorithm

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})x_t >= 01<= y <= 2499999With the initial value of the variable x_t being:x_1 = 19,500The values of the set are:t = [1 2 3 4 5 6 7 8 9 10]The values of the parameters are:A = 21,500B = 0.00095C_t = [50,000 50,240 50,300 51,000 51,040 50,700 50,800 50,200 49,000 48,700]SolvingThe non-linearity in the problem lies in the following product in the constraint:x_{t-1}yWe have implemented the model in AIMMS and tried the Outer Approximation algorithm for this problem, but get the following error message:The generated mathematical program “OA_NLP” has type “QCP” which cannot be changed into “RMINLP”.What might be causing this message? Also, does anyone have suggesti

3
Marcel Hunting
AIMMSian
7 days ago
M
MZwanenburg
asked in AIMMS Developer

For-loop: loop backwards

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.   

8
Chris Kuip
AIMMSian
22 days ago
C
ChunyangEnthusiast
asked in AIMMS Developer

Wrong rank in set data

I defined a set with the element {1..25}, in the data it shows like the figure. What’s the matter? 

2
C
27 days ago
C
ChunyangEnthusiast
asked in AIMMS Developer

How to get the convergence process?

Is there anyway to export the convergence process in one solve?

2
C
27 days ago
C
ChunyangEnthusiast
asked in AIMMS Developer

Is there a function for absolute value?

Hi everyone, is there a predefined function to get the absolute value of variables? 

2
C
28 days ago
C
ChunyangEnthusiast
asked in AIMMS Developer

Unable to access repository

When I tried to add library from repository, I got the error:Unable to get the list of available libraries from repository.Can you tell me how to deal with it?

4
C
23 days ago
M
MZwanenburg
asked in AIMMS Developer

Read data Excel in an order

Hi all, I want to read data from Excel but it should be sorted customly. In Excel the data is like this:  The result in AIMMS should be this:  I can create this with a text join in Excel and paste the value in the data field in AIMMS but the data changes frequently so I want to automate this with AXLL functions. It is important that the order of a, b and c holds.  Does anyone have an idea to do this? 

2
M
1 month ago
luispinto
Administrator
luispintoCustomer Success Manager
published in AIMMS Developer

Publishing, Running and Deleting apps on the CloudNews

I recently published a “how-to” article that provides an example of Python code that can be used to publish a project, run a specific task on it and delete the published project. Use case?“When using a CI/CD pipeline” you may want to test the app as follows: Publish Run scenario Cleanup (including removing the app)  https://how-to.aimms.com/Articles/571/571-publish-run-delete.html

240
luispinto
Administrator
1 month ago
luispinto
Administrator
luispintoCustomer Success Manager
published in AIMMS Developer

How to setup a CI/CD pipeline with AIMMSNews

What is CI/CD?CI/CD introduces ongoing automation and continuous monitoring throughout the lifecycle of apps, from integration and testing phases to delivery and deployment. These are desirable characteristics to have in application development and can be implemented with the context of AIMMS. We recently published an article in our How-To describing the required steps to create a CI/CD pipeline for your AIMMS projects. We try to be as agnostic as possible in terms of platforms.Each pipeline can be setup in a way that better suits your companies needs, such as controlling when a new version is published in testing environment and when it will be published in production.  Check out the article here:https://how-to.aimms.com/Articles/571/571-ci-cd-guide.html

390
luispinto
Administrator
1 month ago
C
ChunyangEnthusiast
posted in AIMMS Developer

How can I formulate multi-layer optimization?

Here is the problem:“k” is a parameter in optimization problem A, for a specific “k1”, we can get the optimum solution “S1” for problem “A”. Now I hope the solution “S” is closer to a specific solution “S*”, so I will need to change the “k” to minimize |S-S*|. How can I formulate this double-layer problem in AIMMS?

4
C
1 month ago
MattC
MattCEnthusiast
asked in AIMMS Developer

Hide Thousands Separators in Scalar Objects

Hello all!  Is there a way to hide thousands separators in WebUI? We want to have years displayed in a scalar widget (e.g. 2023), but currently, WebUI automatically adjusts this data (e.g. to 2,023).  Thank you in advance for your help!

1
gabiservidone
AIMMSian
1 month ago
C
ChunyangEnthusiast
asked in AIMMS Developer

Why I can't constrain the objective variable with inequality？

The objective variable is A(t) contains t = 1 to 24. The mathematical program is to maximize the sum of all the elements in A, i. e. Max sum(A(t)), t = 1 to 24. At the same time I hope to constrain the property of the objective variable that the standard deviation SD(A) is no larger than a constant “a”. So I defined a variable “SD(A) = standard deviation of A”. Then a constraint “SD(A) <= a”. When I run the program, it reminds me of “constraint programming constraints cannot be used in combination with real valued variables, only with integer valued variables, element valued variables, and activities. The real valued objective variable is an exception. The mathematical program has both constraint programming constraints and real valued variables.” However, when I revise the constraint from inequality to equality, i.e. SD(A) = a. Then no error arises and I get the answer. Why dose this happen? And How can I deal with it if I want the inequality constraint?

2
C
1 month ago
C
ChunyangEnthusiast
asked in AIMMS Developer

How can I use part of an index

 Like one day have 24 hours, I need to calculate the variables for 24 periods, but these variables are defined by 25 points, so I define the index t as “25”. For example variable A contains 24 elements, A(1) = B(2)-B(1)…...A(24)=B(25)-B(24).  If I define an index “t” as 25, I can simply define the B as B(t) using t (1 to 25) as the domain. But How can i define A which only contains 24 elements, actually from 1 to 24, can I use part of t domain from 1 to 24? 

2
C
1 month ago
W
waishengEnthusiast
posted in AIMMS Developer

Vehicle Routing Problem on the Constraints

Good day, I am currently working a vehicle routing problem for the refinery simulation VRP. I am model runs without error but couldn’t give out the best solution. I would like to request for assistance upon this issue. Thank you.

3
gabiservidone
AIMMSian
1 month ago
C
ChunyangEnthusiast
asked in AIMMS Developer

How can AIMMS solve different scenarios (initial data) at one run?

I want to run the model with different scenarios (data), can I import all the scenarios once and get the result for each scenario in one run?

4
C
1 month ago
V
ValqueEnthusiast
asked in AIMMS Developer

set and subset in the index domain

Hi community!I have a problem about a formulation and I am looking for help!I have defined a set “Input” index i, and two subsets “input1d” index id and “input1s” index is. Here is my formulation of a constraint:Identifier : MassConservation12Index domain : (i,id,is,r)Definition : sum(t, S1(i,t,r))+Stock1(i,r-1)=sum(d, Y1(id,d,r))+sum(s, uu1(is,s,r))+Stock1(i,r)+ZZ1(id,r) Should I modify the index domain in order to make clear that id and is are subsets of i? Thank you!

2
V
1 month ago
Chris Kuip
AIMMSian
Chris KuipAIMMSian
posted in AIMMS Developer

Dynamically assign value

I recently got the question, how to assign a value to a given parameter; for instance the end user enters the name of a configuration parameter and its new value. This question is similar to obtaining the value of an arbitrary identifier, and runtime libraries can be used to code this generically; see https://how-to.aimms.com/Articles/146/146-value-dynamic-identifier.htmlI created a small example model, whereby three parameters can be changed by naming them in the bottom scalar widget and entering a new value as illustrated below:Demo app after entering a value for AB987.Please find the demo app attached to this post.

0
Chris Kuip
AIMMSian
2 months ago
R
RwitamJExplorer
posted in AIMMS Developer

How to use parallel solver session in a AIMMS project

We are trying to use multiple solver session to solve a large scale problem. We have taken the case of flow shop problem given in AIMMS. We are trying to change the “Number of parallel workers = 2/3/4”, but after solving it is resetting this value to 1 after solve and the solution time is also not improving. We have used the following for delegate to serverif not ProjectDeveloperMode then    if pro::DelegateToServer(timeout : 108000000,completionCallback:'pro::session::loadResultsCallBack', waitforcompletion:1) then        return;    endif;endif;Kindly help and let us know how to use multiple solver session for a large scale optimization problem. Thanks.

0
R
2 months ago
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