Plot loops as plate notations

[yebai]

The current plotting extensions will "unroll" all loops, resulting in a rather cluttered graph. It would be good to investigate whether it is possible to plot loops as plate notations, as in the original BUGS software.

[sunxd3]

Plate notation maybe available via Tikz and bayesnet.
But in general this is difficult, because sometimes the BUGS program is not regular as the original graph interface of BUGS, because programmer can create indices more freely.

A possible approach is to do some graph analysis and put nodes with common parents and/or children in the same class and plot the classes.

[sunxd3]

daft looks like a good candidate for the work.

[yebai]

But in general this is difficult, because sometimes the BUGS program is not regular as the original graph interface of BUGS, because programmer can create indices more freely.

Not sure I understand your point fully. But maybe one can check whether all LHS indices are loop variables (instead of the derivative of loop variables), and only plot in plate notations when this constraint is satisfied.

[sunxd3]

But maybe one can check whether all LHS indices are loop variables (instead of the derivative of loop variables), and only plot in plate notations when this constraint is satisfied.

This can be done, and actually align with my recent thinking. A lot of BUGS programs fits this constraint, I would love to support the plate notation for these models.

[sunxd3]

Drawing plate with respect to nodes seems to be a hard job, I think both bayenet(tikz) and Daft requires some level of manual maneuver. Maybe we can use color to say "these nodes are in the same plate" and have a legend explain the plate variable.

[sunxd3]

Also, a good starting point now is to define a subset of BUGS that's easy to draw.
For instance, one variable should only appear once on the LHS, i.e.

x[1] = ...
for i in 2:3
    x[i] = ...
end

is not allowed.

The indices can only contain loop variable and constant.