ABACUSS II is the next generation open modeling environment and simulator. Designed from the ground up to be as flexible as possible, ABACUSS II can be used standalone or embedded within another application. For example, ABACUSS II is available as a shared library (DLL in Win32) where it can be used with the graphical user interface (GUI) provided or readily used with a custom user interface (e.g., created using Visual Basic) to solve a wide variety of problems. Alternatively, ABACUSS II can be easily and seamlessly embedded within another application (e.g., Microsoft Excel or an automation software system) where the full functionality and power of ABACUSS II can be obtained with a single click of a button.

ABACUSS II has been deployed in a mission-critical industrial application where the users easily constructed a Visual Basic interface customized for their particular problem. The operators using ABACUSS II were presented with this customized GUI (where the additional features of ABACUSS II were hidden from them) greatly increasing ease-of-use and simplifying training; it appeared as though ABACUSS II was designed specifically for their problem!

The figure below contains a diagram of the architecture adopted when designing ABACUSS II.

The layered design is what gives ABACUSS II its flexibility. The top interface level is where the user communicates with ABACUSS II (this communication may be through an external data interface connected to a database). At this level the user can interact with the rest of ABACUSS II through a command-line interface (CLI) or GUI provided with the system or a GUI created specifically for a particular application. Documentation on creating custom interfaces using FORTRAN or Java or Visual Basic is available.

The middle layer is the ABACUSS II input file translator, symbolic environment, and simulation executive. This part of ABACUSS II is available as a static or shared library.

The bottom layer of the architecture is the numerical environment. Here, the numerical components of the DAEPACK system are used to solve a wide variety of problems. Additional functionality provided by DAEPACK are:

• A means for readily incorporating third party numerical algorithms in order to extend the capabilities of ABACUSS II and
• A means for incorporating heterogeneous models (e.g., models written in Fortran-90 rather than the ABACUSS II input language) into ABACUSS II and automatically extracting the necessary information (e.g., analytical derivatives, sparsity patterns, etc.) required when using the state-of-the-art numerical algorithms provided.

Current users can find a detailed description of the ABACUSS II input file syntax by following this link.

You can download a tutorial with screenshots of ABACUSS II.

This is documentation for Agraph (Abacuss graph), a companion program which plots selected ABACUSS II output.

You can download ABACUSS II from this site.

Information about other projects currently under development can be found by following these links...

DAEPACK site

DSL48S site

Jerry Clabaugh
Project Programmer
Phone: 1.617.253.6642
Fax: 1.617.258.5042

Paul I. Barton
Associate Professor of Chemical Engineering
Phone: 1.617.253.6526
Fax: 1.617.258.5042
Email: pib at mit.edu
Web: http://web.mit.edu/cheme/people/faculty/barton.html

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