Minimal cyclic dependent DAEs

[YingboMa]

julia> using ModelingToolkit

julia> @variables t x(t) y(t) z(t) ;

julia> @derivatives D'~t;

julia> eqs = [
           D(z) ~ x + y + z
           0 ~ x - sin(y)
           0 ~ y - cos(x)
       ];

julia> alias_elimination(ModelingToolkit.flatten(ODESystem(eqs))).eqs
ERROR: AssertionError: islinear(ex, vars)
Stacktrace:
 [1] A_b(eqs::Vector{Equation}, vars::Vector{Operation})
   @ ModelingToolkit ~/.julia/packages/ModelingToolkit/CEB9b/src/solve.jl:51
 [2] solve_for(eqs::Vector{Equation}, vars::Vector{Operation})
   @ ModelingToolkit ~/.julia/packages/ModelingToolkit/CEB9b/src/solve.jl:68
 [3] alias_elimination(sys::ODESystem)
   @ ModelingToolkit ~/.julia/packages/ModelingToolkit/CEB9b/src/systems/reduction.jl:57
 [4] top-level scope
   @ REPL[132]:1

[shashi]

Not sure if this is possible to reduce though right?

[shashi]

julia> eqs = [
           D(z) ~ x + y + z
           0 ~ x - y
           0 ~ y - x
       ];

hangs right now though...

[ChrisRackauckas]

@YingboMa what's this?

[YingboMa]

This absolutely works right now :-)