ASCEND capabilities: Difference between revisions
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== Language features == | == Language features == | ||
* Equation-based language | * Equation-based language, see ''[http://ascend.cheme.cmu.edu/ftp/pdfPapersRptsSlides/processModeling.pdf Equation-based Process Modeling]'' for an overview. | ||
* Full support for [[units of measurement]]; user never needs to worry about conversion factors. | * Full support for [[units of measurement]]; user never needs to worry about conversion factors. | ||
* Hierarchical [[MODEL]]s allowing modular system models built from reused components | * Hierarchical [[MODEL]]s allowing modular system models built from reused components | ||
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== Solver features == | == Solver features == | ||
* Detection of singular and non-square equation systems | * Detection of singular and non-square equation systems; user is advised on what modifications would help to make system square. | ||
* Steady-state [[QRSlv]] solver with block decomposition | * Steady-state [[QRSlv]] solver with block decomposition | ||
* Optimisation solver [[IPOPT]] as well as linking to commercial [[CONOPT]] solver | * Optimisation solver [[IPOPT]] as well as linking to commercial [[CONOPT]] solver | ||
* ODE and DAE | * ODE and DAE solver for [[dynamic modelling]]: [[IDA]], [[RADAU5]], [[LSODE]] | ||
* Some preliminary support for dynamic switching models with boundaries | * Some preliminary support for dynamic switching models with boundaries, see [[integration of conditional models]]. | ||
* Solver parameters can be set from within the model code (see [[SOLVER]] and [[OPTION]] statements) | * Solver parameters can be set from within the model code (see [[SOLVER]] and [[OPTION]] statements) | ||
* New solvers can easily be added, implemented as [[external libraries]] that access our Solver API. | * New solvers can easily be added, implemented as [[external libraries]] that access our Solver API. | ||
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* Interactive exploration of the numerical/convergence behaviour of the model | * Interactive exploration of the numerical/convergence behaviour of the model | ||
* Capture the state of selected variables for export/plotting via [[Observer]] functionality | * Capture the state of selected variables for export/plotting via [[Observer]] functionality | ||
* View incidence matrix showing block-decomposed structure of steady-state systems | * View [[incidence matrix]] showing block-decomposed structure of steady-state systems | ||
* Diagnose blocks in the model which have been giving numerical problems | * Diagnose blocks in the model which have been giving numerical problems | ||
* View dependency graph for solution process | * View [[incidence graph]] (aka dependency graph) for solution process | ||
* Plot the time-varying values from the solution of dynamic problems | * Plot the time-varying values from the solution of dynamic problems | ||
* Alpha-quality [[canvas-based modeller for ASCEND]] allows 'wiring up' of graphical 'blocks' to construct complex flowsheets | * Alpha-quality [[canvas-based modeller for ASCEND]] allows 'wiring up' of graphical 'blocks' to construct complex flowsheets | ||
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* {{src|models/thermodynamics.a4l}} code for basic-level accuracy of pure species as well as mixtures | * {{src|models/thermodynamics.a4l}} code for basic-level accuracy of pure species as well as mixtures | ||
* [[FPROPS]] code for accurate calculation of pure species properties | * [[FPROPS]] code for accurate calculation of pure species properties | ||
* linkage to [[freesteam]] library for calculation of steam properties by official IAPWS-IF97 correlations. | |||
* A range of models for [[Energy system modelling with ASCEND|energy system modelling], including [[Brayton cycle]], [[Rankine cycle]] and several solar thermal energy component models. | * A range of models for [[Energy system modelling with ASCEND|energy system modelling], including [[Brayton cycle]], [[Rankine cycle]] and several solar thermal energy component models. | ||
* Models of mixers, separators and reactors for chemical process modelling (eg {{src|models/flash.a4l}}) | * Models of mixers, separators and reactors for chemical process modelling (eg {{src|models/flash.a4l}}) | ||
Latest revision as of 05:09, 3 April 2013
The following is a summary of current ASCEND capabilities. It is intended to be a complete list. If you want a more general/introductory overview, see the ASCEND overview. The main page for accessing greater detail on these topics is our documentation index. This page emphasises the newer PyGTK-based GUI for ASCEND. An overview of the features of the older Tcl/Tk GUI is can be obtained from the TclTk screenshots.
Language features
- Equation-based language, see Equation-based Process Modeling for an overview.
- Full support for units of measurement; user never needs to worry about conversion factors.
- Hierarchical MODELs allowing modular system models built from reused components
- Procedural initialisation of models and solver parameters using METHODs
- WHEN syntax for conditional modelling also known as 'variable-structure modelling'.
- Differential as well as algebraic equations can be expressed
- Constants are declared separately from variables
- Multi-modal models with SWITCH statement (switching based on values assigned to constants).
- Externally-defined equations ('external relations') can be added to models via shared libries and the IMPORT statement
- Can run arbitrary Python code in METHODs via ExtPy linkage, useful for custom plotting, reporting, and model initialisation.
Solver features
- Detection of singular and non-square equation systems; user is advised on what modifications would help to make system square.
- Steady-state QRSlv solver with block decomposition
- Optimisation solver IPOPT as well as linking to commercial CONOPT solver
- ODE and DAE solver for dynamic modelling: IDA, RADAU5, LSODE
- Some preliminary support for dynamic switching models with boundaries, see integration of conditional models.
- Solver parameters can be set from within the model code (see SOLVER and OPTION statements)
- New solvers can easily be added, implemented as external libraries that access our Solver API.
GUI features
- View all aspects of a model in a hierarchical tree view
- FIX and FREE variables interactively, set their values, and quickly re-solve the model.
- Interactive exploration of the numerical/convergence behaviour of the model
- Capture the state of selected variables for export/plotting via Observer functionality
- View incidence matrix showing block-decomposed structure of steady-state systems
- Diagnose blocks in the model which have been giving numerical problems
- View incidence graph (aka dependency graph) for solution process
- Plot the time-varying values from the solution of dynamic problems
- Alpha-quality canvas-based modeller for ASCEND allows 'wiring up' of graphical 'blocks' to construct complex flowsheets
Thermodynamics and Engineering features
- models/thermodynamics.a4l code for basic-level accuracy of pure species as well as mixtures
- FPROPS code for accurate calculation of pure species properties
- linkage to freesteam library for calculation of steam properties by official IAPWS-IF97 correlations.
- A range of models for [[Energy system modelling with ASCEND|energy system modelling], including Brayton cycle, Rankine cycle and several solar thermal energy component models.
- Models of mixers, separators and reactors for chemical process modelling (eg models/flash.a4l)
- A growing model library with a wide range of examples and reusable models.