A implementation for CAD

[papyDoctor]

Hello,
Following our discussion here, I've done a small crate from my project where all the rendering and ui are removed to concentrate on the constraint problem, you can find it here. Was a lot of work to bind my data structure to yours.
In the example, I've four points on which I can apply constraint like segment parallel, horizontal, vertical, point fixed, point fixed on x axis, point fixed on y axis...
If I've exactly 8 equations then it's a determined system and the solver find every time the solution.
But if I remove a constraint (undetermined system), sometimes it converges, sometime not.
I can arrange to have always determined system but it will be not easy I think.

What do you think about this?
And do you plan to use Fear soon?

Olivier

[pnevyk]

Thanks!

Was a lot of work to bind my data structure to yours.

If you have any thoughts on how this experience could be improved, I would love to hear that. Were there any specific obstacles? Or would you imagine the API structured differently?

But if I remove a constraint (undetermined system), sometimes it converges, sometime not.

Just to be sure, success/failure is deterministic right? So for a specific problem with specific initial values it always either succeeds or fails.

Likely not the problem, but I suggest to zero the rx vector at the beginning of eval (I believe you could use rx.fill(0)). It's not guaranteed that the passed vector is all zeros (the implementation might use various temp vectors), so zeroing it manually makes sure that there are no leftover non-zero values causing the solver to think that it didn't converge. (I have an idea how to support underdetermined systems more conveniently API-wise, but until then, this is necessary.)

In order to debug the problematic cases, can you install a log-compatible logger (e.g., env_logger) and set it to output debug level logs? It will print a lot of things, but it should give a better idea about what is going on under the hood. If it is possible, you could also paste the logs here so I can try to make sense out of them.

And do you plan to use Fear soon?

Yes, this migration is planned for the upcoming weeks in my job, so unless something unexpected happens, I believe that it will be released soon-ish.