AIMMS Developer

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

  • 607 Topics
  • 1,330 Replies

607 Topics

Z
AIMMS Partner
Zsolt MihályAIMMS Partner
asked in AIMMS Developer

What is the easiest way to find out whether a constraint is binding?

Ideally, I need this information while running a procedure. I would like to assign it to a parameter. Is there maybe a constraint suffix that I could use to get this information? I’m thinking about something like this: ParameterValue := Constraint.binding

1
Marcel Hunting
AIMMSian
8 months 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?

8
C
2 months ago
B
BasteExplorer
asked in AIMMS Developer

Going from Gross Cash Flow to Net Cash Flow without introducing Non-Linearity?

Hello guys! I have a bit of a problem, I am working in a model that includes Gross Cash Flows (in the model defined as Variables, V_GrossCashFlow), which can be positive or negative of course. If the Gross Cash Flows are positive, then a Tax Rate should be applied to them, resulting in Net Cash Flows (V_NetCashFlow). If the Gross Cash Flows are negative, then Net Cash Flow will just be equal to the Gross Cash Flow. For the V_Net Cash Flow variable I am using a definition such as the following:if (V_GrossCashFlow(tr) > 0 [€]) then    V_GrossCashFlow(tr) * (1 - P_TaxationRate)else    V_GrossCashFlow(tr)endif;The obvious problem with this is that the model goes from being LP to NLP. I was wondering if you guys had any idea to model this situation without introducing Non-Linearity. I have tried using binary variables a bit, but every solution I can find with them forces me to define the binary variable using V_GrossCashFlow anyway, so the model is still Non-Linear.I would be very thankf

1
Marcel Hunting
AIMMSian
1 month ago
User Support
AIMMSian
User SupportAIMMSian
posted in AIMMS Developer

Resolve License Error: Nodelock file is read-only

[h2]Error: Update failed - The nodelock file is readonly[/h2][h3] [/h3][h3] [/h3]You are unable to update your license because the nodelock file is read-only. How to resolve, read [url=https://how-to.aimms.com/Articles/89/89-license-nodelock-error.html]here[/url].

0
User Support
AIMMSian
4 years ago
User Support
AIMMSian
User SupportAIMMSian
posted in AIMMS Developer

How to check whether a given combination of value assignments for the variables in your model satisfy all the constraints to produce a feasible solution.

This article explains how to check whether a given combination of value assignments for the variables in your model satisfy all the constraints to produce a feasible solution. You could add an assignment constraint for each of your variables that fixes the variable to the given value and then solve the model again. If the solver returns with the status infeasible, you know that these variable values do not satisfy all constraints. [url=https://how-to.aimms.com/Articles/193/193-check-if-variables-satisfy-constraints.html]Here[/url]

0
User Support
AIMMSian
4 years ago
MattC
MattCEnthusiast
asked in AIMMS Developer

AXLL Library: Keeping Workbook Open for Multiple Procedures

Hello all!I am working with a large Excel file that is used across multiple procedures. Loading/opening the Excel file into memory using axll::OpenWorkbook takes a very long time as a result of its size (think almost a minute long), and if at all possible, I would like to keep it open even after one procedure is done running such that the next procedure does not need to spend the time re-opening the workbook again.My observation is that AIMMS automatically closes a workbook once a procedure is done running. Is there a way/option somewhere to keep the book loaded into memory? It would save our users quite a bit of time!Thank you in advance!

1
Chris Kuip
AIMMSian
11 months ago
M
AIMMS Partner
Marc WingenderAIMMS Partner
asked in AIMMS Developer

model edit create input argument

Hello, Is there a way to define an input argument via model edting? I know I can create a procedure and define the body e.g.: {    _eProc := me::Create(_spProcName, 'procedure', _eSection);    me::SetAttribute(_eProc, 'body', _spBody);}

3
M
AIMMS Partner
8 months ago
Jess Es
Administrator
Jess EsCommunity Manager
published in AIMMS Developer

How to Determine Data Ranges in Excel FilesHow-To

You can provide Excel cell ranges as input data to AIMMS AXLL functions. Here we show how to adapt when the ranges are unknown, for example, when end users upload Excel files as input in the AIMMS app.   We include a modified version of the exampleNFL project used in AIMMS Excel Library - AXLL.   Read more...

380
Jess Es
Administrator
3 years ago
luispinto
Administrator
luispintoCustomer Success Manager
published in AIMMS Developer

Demo impressions 4/3/2022

New internal demo and here I am to share! Remember what I share here is not (necessarily) released yet and can change or even be discarded! I just give the scoop.Connecting the dots is a new functionality in the combination chart that can allow you to “connect the dots” quite literally! So if you have a line chart and have missing data (for some x values), you can still connect the data that is present.Example of connecting dotsAutomatic conversation of classic charts to new combination chart! I really appreciate the effort into building this functionality making life so much easier, but still maintaining the original chart so you'll always be safe in using this. I also enjoyed the improvement to table filtering explicitly separating regex functionality from others. This is already released:  https://documentation.aimms.com/webui/table-widget.html#regular-expressions

380
luispinto
Administrator
1 year 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
5 months ago
Z
zulfan.adiputraEnthusiast
asked in AIMMS Developer

How much data can be plotted in Histogram of AIMMS?

Hi, I’ve been trying to run some Monte Carlo simulations, but apparently if the number of runs is more than 500, the Histogram cannot be made. AIMMS returns some arithmetic error that I don’t understand. How can we increase the number of data that Histogram can make?Thanks,Zulfan

2
Z
1 year ago
Jess Es
Administrator
Jess EsCommunity Manager
published in AIMMS Developer

How to Align Objects in WinUIHow-To

When creating a WinUI page for your AIMMS project you typically want to [b]align[/b] the page objects. Of course, you could manually determine the pixels where each object should be placed, and use the position/size details in the status bar for the selected page object in developer mode. But this is a bit tedious. Fortunately, there is a better way! [url=https://how-to.aimms.com/Articles/234/234-align-multiple-objects-winui.html]Read more...[/url]

380
Jess Es
Administrator
4 years ago
Z
zlingEnthusiast
asked in AIMMS Developer

Superbasic and At Bound Value

Hi!The model aims to optimize the energy flow in my superstructure and minimize the cost. Most of the data in the listing file show that the status is superbasic and some of them are superbasic, at bound. Here is the message showing on top of the listing file.CONOPT 4.1 constructed the following irreducible infeasibility set (IIS).The IIS consists of 1 constraint and 1 variable.HWH(6) .. [ 9 | 273 | IIS ]    + 1 * Techflow(HW,6) - 0.800 * NGflow(HWH,6) = 0 ; (lhs=-25630, scale=3600000) ****    name              lower   level   upper   scale    Techflow(HW,6)     -inf  -25630     inf 3600000    NGflow(HWH,6)         0       0     inf 3600000  <--- pivot columnThe constraint is stated like this:HWH(t):Techflow('HW',t)=EfficiencyNG('HWH')*NGflow('HWH',t)Attached is the zipped file for my model. I would appreciate if anyone could help me to solve this.

4
Z
1 year ago
Jess Es
Administrator
Jess EsCommunity Manager
published in AIMMS Developer

How to install CDM serviceHow-To

Installing CDM service allows multiple users to collaborate on a single AIMMS model. When developing an application using CDM, the embedded CDM server is ideal, as mistakes and restarts are easily captured by manually switching and/or clearing the database that stores the CDM data. When testing or deploying an application with multiple collaborating users, a CDM service needs to be installed that handles commits by storing the data and informing other users of these commits. [url=https://how-to.aimms.com/Articles/280/280-install-cdm-service.html]Read more...[/url]

380
Jess Es
Administrator
4 years ago
L
LowBjornAce
asked in AIMMS Developer

Database table: Is there a (significant) performance difference between reading a view or a query?

In AIMMS it is possible to read data from both a query, or a selected object (e.g. a view). I was wondering if there is a difference in performance between the two methods if the only goal is to read data.In my case, I am considering reading data from a table valued function because that allows me to filter the data according to several parameters. An alternative is reading from a view, where the parameters would appear in the columns and then used as an ‘Index domain’ when reading the database table in AIMMS.I’m generally interested in performance impact, best practices, and overall trade-offs between alternative data retrieval methods (given a database).

1
mohansx
2 years ago
User Support
AIMMSian
User SupportAIMMSian
posted in AIMMS Developer

How to Investigate Memory in Use

Analytic applications may involve a lot of data and subsequently a lot of computer memory. AIMMS hides the technicalities related to memory management from the model developer. These technicalities include, for instance, the allocation and de-allocation of memory for individual data items. Still, the memory usage of applications created with AIMMS grows as the amount of data related to these applications grows. At some point during model development, the memory usage of your application becomes interesting. AIMMS offers tools to monitor and investigate the memory usage of your application. We will discuss a couple of the tools available in AIMMS to investigate memory usage. [url=https://how-to.aimms.com/Articles/170/170-memory-in-use.html]Here[/url]

0
User Support
AIMMSian
4 years ago
V
AIMMS Partner
vishweshpatilAIMMS Partner
asked in AIMMS Developer

Password Protection

Is there a way to lock a page in Web-UI with a password?

1
Gertjan
AIMMSian
2 years 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
5 months ago
Jess Es
Administrator
Jess EsCommunity Manager
published in AIMMS Developer

How to Display Line Numbers in the EditorHow-To

By default, [b]line[/b] [b]numbers[/b] are hidden in the Editor in the AIMMS IDE. However, you can enable line numbers in settings. This is useful when sharing information about your model, so you can point to specific lines in a procedure or a definition. [url=https://how-to.aimms.com/Articles/232/232-display-line-numbers.html]Read more...[/url]

370
Jess Es
Administrator
4 years ago
User Support
AIMMSian
User SupportAIMMSian
posted in AIMMS Developer

How to share your project with other developers

This article gives you an overview of the folder structure of an AIMMS project, and how to share your project with other developers. Read it, [url=https://how-to.aimms.com/Articles/45/45-share-project-files.html]here[/url]

0
User Support
AIMMSian
4 years ago
User Support
AIMMSian
User SupportAIMMSian
posted in AIMMS Developer

How to use different indices to refer to the elements of a set.

This [url=https://how-to.aimms.com/Articles/184/184-use-multiple-indices-for-set.html]article [/url]explains how to use different indices to refer to the elements of a set.

0
User Support
AIMMSian
4 years ago
Jess Es
Administrator
Jess EsCommunity Manager
published in AIMMS Developer

How to identify data differences after refactorizationHow-to

We'll show you a streamlined process to identify the cause of data differences in a model after a refactorization using a diff tool. The process we’re following can be summarized like this: [list=1] [*]You’ll want to separate out each element, so it will be easy to break down the differences. [*]Then send each identifier to a separate output file in an output folder. [*]Do that for each version of the model, so you’ll have two output folders each containing output files to be compared. [*]Finally you’ll compare the two output folders with a diff tool to find the differences between the individual files. [/list] [url=https://how-to.aimms.com/Articles/290/290-identifying-differences.html]Read more...[/url]

360
Jess Es
Administrator
4 years ago
V
AIMMS Partner
vishweshpatilAIMMS Partner
asked in AIMMS Developer

Element Parameter not giving results

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 

1
mohansx
2 years ago
Jess Es
Administrator
Jess EsCommunity Manager
published in AIMMS Developer

How to Write to a database efficientlyHow-to

This article explores a heuristic for writing to databases safely and efficiently. When AIMMS writes data to a database table, it uses structural information of the database table to determine a safe and efficient strategy for writing. In this article we discuss: An example project Foreign key relations Available strategies Database schema design best practices Read more...

360
Jess Es
Administrator
3 years ago
J
jeromeeeExplorer
posted in AIMMS Developer

Creating Subset probem

Hi, I simply need to make a subset “test” of range from 0 to 10 of set “timehour” which the range is from 0 to 140 But I don’t archieve to do it see picture.When i range “test” from 0 to 100 or more It works but when I’m below 100 it doesn’tHelp me pls   

2
Andrew
2 years ago
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