Timo Stienstra

I agree. Probably best to introduce a new key word argument `constraint_solver` (feel free to suggest a better name). Some options are: - `'lu'`: default using `LUsolve` - `'numeric'`: uses...

@oscarbenjamin First of thank you for this explanation. [`MatrixSolve`](https://github.com/sympy/sympy/blob/4fb6b42dd0941f05178aa570edf9ef61162ce960/sympy/codegen/matrix_nodes.py#L27) is a node in codegen, which translates to `np.linalg.solve` when using `lambdify` with the `NumPyPrinter`. Therefore this is the best solution...

I just quickly went through the error you get when `convert_now=False`. The error is in this line: `force_lam = sm.lambdify(qL + pL, force, cse=True)` The error is caused by taking...

`Derivative(x(t), (t, 2))` is considered to be a dynamicsymbol. Running `me.find_dynamicsymbols(force)` directly after `force = sm.Matrix.vstack(force1, sm.Matrix([rhsx]))` gives: ``` {Derivative(x(t), (t, 2)), Derivative(x(t), t), mx(t), my(t), q(t), u(t), umx(t), umy(t),...

When adding objects to the system, some checking would be nice. The objects that have to be stored and checked are: - Coordinates (dependent and independent) - Should use the...

If a feature were to be introduced [to choose the generalized speeds efficiently](https://github.com/sympy/sympy/pull/24053#issuecomment-1262468801), then a possible addition to the `System` class would be to have specific add joints functions like:...

Above I proposed using `System(origin, frame)`. This is more minimal, however if you'd like to create a joint, you'll know first have to create a body `RigidBody('newtonian', origin, frame)`, which...

A difference between the constraints definition of `KanesMethod` and `LagrangesMethod` is: - `KanesMethod` uses `configuration_constraints` and `velocity_constraints`, where the `configuration_constraints.diff(dynamicsymbols._t)` should be added to `velocity_constraints` on beforehand . - `LagrangesMethod`...

It would be optimal to also have a method that checks whether a system is valid based on some basic checks. Note that we should add here a note that...

Was currently thinking about an `apply_gravity` function. It could be an option to also add an optional argument to either include or exclude certain bodies. There are a lot of...