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Why this articleIn this article, we will explain how Machine Learning and AIMMS can work together to complement the mathematical modeling and optimization capabilities of AIMMS as decision support technology. Why? Because we see an increasing need by our customers to understand its potential. Also, we notice that some users feel they need to choose between one or the other when creating decision support systems. We believe the combination is more powerful. This is also why we make it possible for customers to integrate scripting languages like Python and R with AIMMS models.We will start with a brief introduction to AIMMS and the various disciplines for better decision making (optimization, machine learning and business rules). Hereafter, we explore both machine learning and optimization as techniques, followed by how optimization- and thus AIMMS and AIMMS users - can benefit from machine learning. The idea is not to fully explain the two techniques (there are various resources online)
Hi Aimms Community, I’m having trouble using the Sort function in order to obtain the values of a mulit-dimensional array: For example:multi-dimensional array = foo(size,car,color,location) size, car, color, location = some float value [ ‘small’, ‘toyota’, ‘white’, ‘usa’] = 1.25 [ ‘small’, ‘toyota’, ‘green’, ‘greenland’] = .5 [ ‘small’, ‘nissan’, ‘blue’, ‘france’’] = 1.0[ ‘small’, ‘nissan’, ‘green’, ‘france’’] = .3 In this case we are looking to sort foo by the values for all colors and locations where the size and car are the same, meaning that the result would be put into another variable bar(size,car,row)[ ‘small’, ‘toyota’, 1] = .5[ ‘small’, ‘toyota’, 2] = 1.25[ ‘small’, ‘nissan’, 1] = .3[ ‘small’, ‘nissan’, 2] = 1.0 How do I approach this problem? I looked through the documentation but I see that the Sort operator is really trying to sort by an index of an array and not the values for given indexes. Thanks for any help
Hello everyone,I am new to AIMMS, I am trying to solve a unit commitment problem with four thermal generator units and a PV unit. I have added the four generators in a set with index (u) with all their parameters in the model. Now, I want to add another source of power supply which is PV as a fixed parameter, that is, constant power output. How do I add and index the PV as it’s also a generating unit but with different characteristics? This would also affect my power balance constraints of sum of total power supply equal to load demand.
We solved the MIP optimization model. The characteristics of the models and solution times are given in the table below. We used SQLServer Express for data ETL purposes. Input and output data published in two datasets (Dataset: Podporozhye, Dataset: Estonia) in the MendeleyData repository. We will present the results at the IECF2021 conference in September. Estonia Podporozhye Constraints 2904 3203 Variables 2760 3112 Binary 2759 3111 Nonzeros 36890 20174 CBC, s 1.78 3.75 What is of interest to us as AIMMS users in this case study? The use of AIMMS Community Edition with open solver CBC to find solutions for scientific problems in the first approximation. In other words, AIMMS Community Edition allows us to test different models of the problem on a small data set. @bacherikov_iv , @anastasiiasimonenkova Thanks to AIMMS B.V. for providing the lic
Hi all,I’m sorry of the question is too basic, but I recently had to re-run an old code (originally developed in AIMMS 4.47) and I’m having lots of trouble correcting errors.I have a variable ( Ireal(ld) ) that uses another variable ( Vreal(bus,ph) ) in its calculation.I have an string parameter ( load_bus(ld) ) that has the “bus” value for each “ld” and a parameter ( load_ph(ld) ) that has the “ph” value for each “ld”.In the old code I used Vreal(load_bus(ld), load_ph(ld)) to calculate the Ireal(ld), but in the new AIMMS version (4.88) I keep getting “The scope of string parameter “load_bus” has not been specified”.Can anybody please help me in what I’m missing?Thank you in advance.
Hi all,I'm a researcher and I use AIMMS with an Academic License.AIMMS is part of a routine I developed in Python and I used the "AIMMSSelector" to launch AIMMS, but since my license is now a cloud license I've not been able to launch AIMMS that way, it does not recognize the license, and only give me option to add a stand alone license or a network license server.I've been searching for materials regarding this, but couldn't find any. Can you help me? Here is the code I used to launch AIMMS previously:#Initialize AIMMS sys.argv = ["makepy", "AimmsSelector.Selector64"] AimmsObj = win32com.client.Dispatch("AimmsSelector.Selector64") self.AimmsProj = AimmsObj.GetAimmsProject(f'{self.aimmsFileDir}\\{self.aimmsFileName}') self.AimmsProj.StartupMode = 1 #Start minimized self.AimmsProj.ProjectOpen(f'{self.aimmsFileDir}\\{self.aimmsFileName}', 0)
We have had the pleasure of interviewing many academics about their use of AIMMS. Often, they are working on innovative research projects that will shape the future of our economy for years to come. Edwin Zondervan is one of them. Edwin is a professor of process systems engineering at Twente University and has been using AIMMS for several years. His work focuses on the energy transition and topics surrounding the hydrogen economy, biobased production, carbon capture and utilization, and electrochemical energy storage. We were curious about how he applies AIMMS in these areas. Can you tell us a little bit about yourself and your background? How did your interest in optimization and modeling develop? I was born and raised in Leeuwarden, Friesland – in the north of the Netherlands. I got a bachelor’s degree in chemical engineering with a specialization in process automation. This is where my interest in mathematics and chemical engineering was born. I continued with a master's in chemica
AIMMS has long been in the toolbox of energy modelers. With the field undergoing a lot of change today, we were curious to hear from someone who is at the forefront of both energy modeling and one of the biggest challenges of our time: a transition to low-carbon energy systems. We had the pleasure of speaking with Chiara Bordin, Associate Professor of Energy Informatics at UiT, the Arctic University of Norway.Can you tell us a bit about yourself and your background?I am originally from a small town near Bologna, Italy. I did my master’s degree at the University of Bologna, as well as my PhD. In the last year of my PhD, I had the opportunity to spend some time as a visiting researcher in a foreign university and I decided to go to Durham University, in the UK. There was a lecturer there who was doing very interesting things in energy systems modeling. I felt that working with him would be a good experience, so I went there as a visiting student. I ended up staying there for the full yea
AIMMS has always had a tight relationship with academia, so we love to highlight professors, students and researchers who are using our software to solve problems around the world. Recently, we had the pleasure of speaking with Prof. Nnamdi Nwulu from the University of Johannesburg. Nnamdi recently published a book titled “Optimal Operation and Control of Power Systems Using an Algebraic Modelling Language.” He and his co-author, Dr. Saheed Lekan Gbadamosi, used AIMMS to model and solve many of the mathematical optimization problems found in modern power grids. His book is a great entry point for energy modeling students and practitioners. Its aim is to democratize energy system modeling. Read our conversation below. Let's do a quick round of introductions, would you like to start Nnamdi? Yes. My name is Nnamdi Nwulu and I am an Associate Professor at the University of Johannesburg. I am currently the Director of the Centre for Cyber-Physical Food, Energy & Water Systems (CCP-FEW
Integrated Electricity, Hydrogen and Gas Markets Model (I-ELGAS) The future energy system will be increasingly integrated in order to absorb large fluctuations in intermittent renewables. Electricity, gas and hydrogen markets are interlinked via technologies such as water-electrolysis plants, natural gas reformers as well as natural gas and hydrogen-fired power plants. Analysis of the future interactions between energy supply and demand requires a market-based system allocation model which accounts for interactions between these markets and simultaneously represents the infrastructures in these markets. As the interactions between these markets will only increase in the future, an integrated assessment of these markets and systems is necessary. At TNO Energy Transition, AIMMS is used to model the integrated electricity, hydrogen and gas markets (I-ELGAS). The model analyzes future energy system while considering interactions and linkages between these markets. I-ELGAS model schemat
Hello,Since I'm new to aims, I have (I think) a simple question;How can I do a part of a summation?So for example; I've got x1, x2, x3, x4 and x5 as my sets. In my mathematical model is one constraint: x5 = 10*x1 + 18*x2. How do I get this in AIMMS?
Dear Colleague, I warmly invite you to contribute to the Handbook of Smart Energy Systems project https://meteor.springer.com/hses. Considering the importance of energy production, transmission, and distribution systems on the current and future of human living, to adjust to the new normal life of post-covid and cope with the climate change, this book focuses on enabling solutions for energy access to industry development and the general world population in more reliable and sustainable ways, focusing on improving the performance measures of the energy systems. The proposed book consists of four parts. Reliability enhancement of energy systems This part describes the reliability developments for energy systems. For instance, the reliability of the players in an energy distribution system, reliability of data collection procedures, and reliability of the logistics. The major topics may cover (not limited) are as follows:Importance of data reliability in energy demand forecast Influences
Good afternoon!I would like to invite the community to share their favorite blogs on mathematical programming, operations research, and data manipulation.My favorite blog is http://yetanothermathprogrammingconsultant.blogspot.com/The author of the blog uses GAMS. Models created in GAMS can be converted to AIMMS.https://how-to.aimms.com/Articles/312/312-convert-gams-to-aimms.html
Hi all,Every time we update our app, I get e-mails from users that they cannot enter the app and they send me a picture like the one below. We have tried to prevent this from happening by using the ‘latest’ tag option. All links in our information channels link to our app ending with the ‘/tag/latest’ such that they always end up at the right version of the app. But still I get a lot of these e-mails.Mostly this is because, once people have entered the app, they bookmark it (or store the url) and use this bookmark later on. The problem is that once they bookmark it, the url has changed to the current version name and therefore the link doesn’t consist of this latest tag anymore. And thereby causing the problem of the picture below after a new update of the app. I always reply back that they should use the link with the latest tag in there, but as we have a lot of users, this keeps happening. It would be great if there could be a solution, such that my users don’t have be annoyed by the
Hi,I want to write a floor function in my model.Or how to get floor value of a fractional number?how can i write that in AIMMS?
The data for leading times, phasing in capital and life of plant was imported to the model. A new declaration called Lead times was added. It looks like this: All the identifiers in the Lead Times declaration are supposed to take care of the leading times, phasing in capital and economic life. However, that is not happening. Ideally:The new power plants are supposed to be committed any time between 2013 and 2050. No new capacity is supposed to start at 2013 because of leading times. Those power plants with life of plant that pass 2050 are supposed to remain active until their corresponding life of plant comes to an end. Not all the capital can be taken in one year for new capacity, but a portion per each year of the leading time, according to p_phaseIn parameter.The attached model, opens on this page:One will have to:Click the input data button Select the scenario analysis, then click solve the scenario button. This solves the deterministic model. The corresponding results can be view
I have been trying to import the phasing in capital data which is in the attached Excel file. I have added the identifiers on the attached word file. The data I am importing has numbers which I want AIMMS to convert to percentages.On my side the PhasingInCapital is a worksheet inside the Input Data workbook. Here is the error:ExcelSetActiveSheet(Input Data.xlsx, PhasingInCapital) failed: Workbook doesn't contain the specified sheet. Invalid index.I have imported a lot of data files from Excel, I am not sure what am I doing wrong this time.Please assist.
ODH-CPLEX is a high performance solver for Mixed Integer Programming (MIP) and Mixed Integer Quadratic Programming (MIQP/MIQCP) problems. ODH-CPLEX uses the CPLEX solver underneath and is made to run on modern multiprocessor machines. While it is designed for scheduling problems, it’s been deployed effectively on packing and other supply chain applications as well. We have noticed considerable runtime improvements for customers who use the CPLEX solver and ODH add-on. To give you more insight into these benefits, we invited the solver’s creators, Optimization Direct, for a webinar. Get a summary below or watch the full presentation by Dr. Robert Ashford and Dr. Alkis Vazacopoulos here. Improving Solve Times for Large Scale Optimization As supply chains become more complex, models are becoming larger and equally complex to run. ODHeuristics offers a toolset for handling large and/or difficult MIPs. The ODH-CPLEX solver goes further than CPLEX in finding an initial solution. It improves
Hi, My model took more than 14 days to run on i7 core computer with 16GB RAM. And it still does not give an optimal solution yet. What will happen if we stop AIMMS during the middle of running a model when the solution is not optimal yet? The gap in progress window shows 38.2% for 10 days (see attached picture), then it drops to 38.1% on day-13. From what I understand, the gap is the difference between a best known solution and the best bound. If I set the gap to certain values, which part of the model will be affected? Will all the constraints be satisfied/evaluate? Or will AIMMS only satisfied half of the constraints? For your information, my objective is to maximize the preferences of the lecturer. My preferences parameter has the range values from 1 to 5, where 1 is least preferred while 5 is the most preferred. Can anyone help me? Thank you in advance! Gap on Day-12
Good day, I have an electricity capacity expansion planning model which was developed in AIMMS and is working fine. However, now I need to add the following:Lead times, which differ for each technology. Currently, the model assumes that if a technology is selected by the model, it can produce electricity as soon as the model makes it available for capacity allocation. I need this to change and the model should make the technology’s capacity available after the lead time has expired. Phasing in capital, which also differ for each technology. The current model assumes that the capital for a chosen technology is payable immediately. The phasing in capital are connected to lead times. For example if a technology has a lead time of 2 years, the phasing in capital is also over 2 years, say 90% of capital is payable in year 1 and 10% in year 2. I need the capital for each technology to be phased in according to the phasing in capital percentages. Life of plant (Economic life), which also dif
Hello dear AIMMS Community, currently im working on a simulation of robots driving in a parking garage and charging electric vehicles.The first step is done and it is kind of working, but i have currently two major problems. even if i am not putting any demand on the parking lot the robots drive to the lot and “simulate” charging an electric vehicle. → i tried to find a solution in the community, but i was not successful. Is there any possibility, any constraint which could make the robot not to service/drive to that parking lot while Demand(i)=0. As you can see in the picture: even if i put Demand of almost every parking lot=0, the robot drives to all the places, before going back to the depot. Another problem is, that i want to make the robots drive on a specific route, shown as yellow in the picture/simulation. → Is there any chance of making the robots drive a minimum besides the yellow route? My thought is that, despite being able to create that, later in the mathimatical pr
Hello, I am a Master Student at the University of Applied Sciences. I found your website by chance, because you have knowledge in production management. Recently we started working in production management with the software AIMMS. However, I don't know how to transfer or programming the simplex-modeling, which I solved mathematically, into AIMMS. Can you help me with this?
Dear Community; We are working with some MILP problems where we need to identify the ShadowPrice of some constraints. These constraints are made up of both binary and continuous variables. As the duality is not well defined for MILP problems, one method to find the ShadowPrice is to run a LP fixed model right after MILP solution. I see that AIMMS provide ShadowPrice by default for MILP problem when the variable property “ShadowPrice” is defined.