Diagnose tool

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This page documents an experimental feature. Please tell us if you experience any problems.

This is an element of the PyGTK GUI that is intended to provide the user with additional solver-derived information regarding block structure of their models. At present it only really works with the NLA solvers such as QRSlv.

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Screenshot of the Diagnose window in ASCEND PyGTK.

Essentially, this window aims at

  1. providing a clear indication of the block structure of a model's equations and variables after reordering (read Piela's "Equation based modeling" from our publication list for some good background on that
  2. showing exactly which variables and equations are present in a particular block, hopefully in a fairly intutiive/easy form,
  3. giving some indication when there are variables at their upper/lower bounds, as that often gives a clue about the reason for divergence of the solver,
  4. giving some indication when variables have a very small/large value relative to their nominal value, as that gives a clue when a variable might be badly scaled, reducing the effectiveness of the solver.

See also How do I fix my model