Incidence graph

This page documents an experimental feature. You can help out by testing it and recording your experiences.

You can create an incidence graph and view it on-screen if your copy of ASCEND is linked to GraphViz. We have currently only tested this on Linux, but it should transfer to Windows without too many problems.

To show the incidence graph, use the Tools->Incidence Graph menu option in the PyGTK GUI.

For the simple models/johnpye/reynolds.a4c model, the following incidence graph results:

Incidence graph for models/johnpye/reynolds.a4c.

A more complex example is this one, which represents a basic Rankine Cycle power station (models/johnpye/fprops/rankine_fprops.a4c):

Incidence graph for a simple Rankine Cycle calculation (models/johnpye/fprops/rankine_fprops.a4c). Note the upward arrow from the 'mdot' box, which implies some iteration is necessary in the solver.

In both of these diagrams, the fixed variables are shown in green; all other variables are shown in boxes, and equations are shown in ellipses.

There are limits to how complex a model is allowed to be when creating these incidence graphs, with the above being close to the limit of what's really practicable.

We plan to improve the graph by ranking the variables, so that they appear down the page in the order that ASCEND solves them.

See also

• Graphical block debugging
• Incidence matrix