APMonitor

There are references to APMonitor and Gekko in published articles. If you use APMonitor or Gekko, please consider citing the following articles.

• Hedengren, J. D. and Asgharzadeh Shishavan, R., Powell, K.M., and Edgar, T.F., Nonlinear Modeling, Estimation and Predictive Control in APMonitor, Computers and Chemical Engineering, Volume 70, pg. 133–148, 2014, doi: 10.1016/j.compchemeng.2014.04.013. Article - Google Scholar Citations
• Beal, L.D.R., Hill, D., Martin, R.A., and Hedengren, J. D., GEKKO Optimization Suite, Processes, Volume 6, Number 8, 2018, doi: 10.3390/pr6080106. Article

Benjamin Spivey
Energy Systems Modeling and Control
Department of Chemical Engineering
University of Texas at Austin

APMonitor modeling language has significantly reduced the time required to develop a fuel cell plant model that is central to my PhD dissertation. The modeling language provided an intuitive interface to model a distributed parameter, differential-algebraic dynamic system containing an implicit set of nonlinear algebraic equations. Since the DAE index is greater than 1, this problem could not be solved using Matlab's DAE mass matrices. I was able to quickly test several solvers, APOPT, BPOPT, and IPOPT, that can be interfaced with APMonitor by changing a single parameter. The language has provided a wide variety of configuration parameters to provide control over convergence criteria, varying levels of output for model debugging, and solver modes. A major benefit of the program is inclusion of many advanced solution modes: steady-state and dynamic simulation, parameter identification, real-time optimization, nonlinear control (NLC), and moving horizon estimation (MHE). My only personal experience with similar software is AMPL. The software can be compared to AMPL and GAMS but is unique from these in that it accepts DAE models and performs time discretization automatically versus an algebraic modeling format. The modeling interface is more similar to Honeywell NLC, but it includes additional solution modes, such as MHE, besides nonlinear control. The software may also be compared to gProms; however, gProms is recommended primarily for simulation, and researchers from our lab have reported difficulty linking gProms with a control algorithm. APMonitor competes with similar software in different aspects, but it is unique in the breadth, ease of use, and availability as a freeware software. In addition, an online interface helps facilitate their product support. As a fairly new software platform, APMonitor has had fewer field applications than more established software, but given its benefits, I expect field experience to continue increasing.

Prof. Klaus Schittkowski
Department of Computer Science
University of Bayreuth
D - 95440 Bayreuth, Germany

Your modeling language seems to be very clear and intuitively usable. I like it very much.

Jeff
Department of Chemical and Biomolecular Engineering
Clemson University

Greetings from Clemson University's Department of Chemical and Biomolecular Engineering in South Carolina. I am a senior biomolecular engineering major who is graduating in May. I have watched an extensive amount of your course material covering process dynamics and control and I am now beginning to branch out into some of your other course topics. I was going to leave a YouTube comment containing this information, but I assumed it would probably be overlooked, therefore I wanted to send you an email personally. Thank you for making your materials available online. Not only that, but for providing such a comprehensive amount of corresponding courseware along with the lecture videos, such as the syllabus, course outline and schedule, and much more. I have used your videos for over a year and am now branching out to more advanced courses that you provide, especially dynamic modeling and Python programming. I know it is easy to overlook the influence you make online via these courses, so I wanted to send you a letter reminding you that you are making an enormous difference. Even though you don't directly hear a "thank you" from every viewer that benefits, don't take this to mean that we are not truly thankful.