option to set all dummy derivatives to zero in linearize

[baggepinnen]

No description provided.

[YingboMa]

Does Julia 1.6 not like ControlSystemsMTK?

[YingboMa]

Could you change the tests such that ControlSystemsMTK isn't needed?

[baggepinnen]

I don't think that ControlSystemsMTK is the problem, since ControlSystemsMTK tests pass on julia v1.6 without problems. I'd also like to keep it as kind-of a downstream test that the simplification in named_ss when input derivatives are present is working as expected.

Running it on v1.6 locally indicates that using ControlSystemsMTK runs, and it gets stuck on

@named link1 = Link(; m = 0.2, l = 10, I = 1, g = -9.807)

If I put @show in front of

@show @parameters t
@show D = Differential(t)

@show @named link1 = Link(; m = 0.2, l = 10, I = 1, g = -9.807)
@show @named cart = Translational.Mass(; m = 1, s_0 = 0)
@show @named fixed = Fixed()
@show @named force = Force()

I get this printed before it gets stuck

#= /home/fredrikb/.julia/dev/ModelingToolkit/test/linearize.jl:181 =# @parameters(t) = Symbolics.Num[t]
D = Differential(t) = Differential(t)

[baggepinnen]

I disabled those tests for Julia v1.6, so the tests are passing now. We could open a separate issue with the freezing of

@named link1 = Link(; m = 0.2, l = 10, I = 1, g = -9.807)