Autodiff fails mysteriously with well-defined nested defaults #2997
Description
I am very confused by this. On my computer, the example
using ModelingToolkit
using ModelingToolkit: t_nounits as t, D_nounits as D
using ForwardDiff
pars = @parameters y0 mh Tγ0 Th0 h ργ0
vars = @variables x(t)
@named sys = ODESystem([D(x) ~ y0], t, vars, pars; defaults = [
y0 => mh*3.1 / (2.3*Th0),
mh => 123.4, # change to 123.3 and everything runs (???)
Th0 => (4/11)^(1/3) * Tγ0,
Tγ0 => (15/π^2 * ργ0 * (2*h)^2/7)^(1/4) / 5,
])
sys = structural_simplify(sys)
function x_at_0(θ)
prob = ODEProblem(sys, [sys.x => 1.0], (0.0, 1.0), [sys.ργ0 => θ[1], sys.h => θ[2]])
return prob.u0[1]
end
ForwardDiff.gradient(x_at_0, [0.3, 0.7])(where all parameter defaults follow from ργ0 and h) unexpectedly fails with
ERROR: LoadError: MethodError: isequal(::ForwardDiff.Dual{ForwardDiff.Tag{typeof(x_at_0), Float64}, Float64, 2}, ::Num) is ambiguous.
Candidates:
isequal(x::ForwardDiff.Dual{Tx}, y::Real) where Tx
@ ForwardDiff ~/.julia/packages/ForwardDiff/PcZ48/src/dual.jl:144
isequal(a::Number, b::Num)
@ Symbolics ~/.julia/dev/SymBoltz/dev/Symbolics/src/num.jl:131
Possible fix, define
isequal(::ForwardDiff.Dual{Tx}, ::Num) where Tx
Stacktrace:
[1] ht_keyindex(h::Dict{Any, Any}, key::ForwardDiff.Dual{ForwardDiff.Tag{typeof(x_at_0), Float64}, Float64, 2})
@ Base ./dict.jl:275
[2] get
@ ./dict.jl:524 [inlined]
[3] #fast_substitute#246
@ ~/.julia/dev/SymBoltz/dev/Symbolics/src/variable.jl:474 [inlined]
[4] fixpoint_sub(x::SymbolicUtils.BasicSymbolic{Real}, dict::Dict{Any, Any}; operator::Type)
@ Symbolics ~/.julia/dev/SymBoltz/dev/Symbolics/src/variable.jl:432
[5] fixpoint_sub(x::SymbolicUtils.BasicSymbolic{Real}, dict::Dict{Any, Any})
@ Symbolics ~/.julia/dev/SymBoltz/dev/Symbolics/src/variable.jl:426
[6] (::ModelingToolkit.var"#126#134"{Dict{Any, Any}})(::Pair{Any, Any})
@ ModelingToolkit ./none:0
[7] iterate
@ ./generator.jl:47 [inlined]
[8] _all(f::Base.var"#384#386", itr::Base.Generator{Dict{Any, Any}, ModelingToolkit.var"#126#134"{Dict{Any, Any}}}, ::Colon)
@ Base ./reduce.jl:1297
[9] all
@ ./reduce.jl:1283 [inlined]
[10] Dict(kv::Base.Generator{Dict{Any, Any}, ModelingToolkit.var"#126#134"{Dict{Any, Any}}})
@ Base ./dict.jl:111
[11] MTKParameters(sys::ODESystem, p::Dict{…}, u0::Vector{…}; tofloat::Bool, use_union::Bool, t0::Float64)
@ ModelingToolkit ~/.julia/packages/ModelingToolkit/K6okj/src/systems/parameter_buffer.jl:109
[12] process_DEProblem(constructor::Type, sys::ODESystem, u0map::Vector{…}, parammap::Vector{…}; implicit_dae::Bool, du0map::Nothing, version::Nothing, tgrad::Bool, jac::Bool, checkbounds::Bool, sparse::Bool, simplify::Bool, linenumbers::Bool, parallel::Symbolics.SerialForm, eval_expression::Bool, eval_module::Module, use_union::Bool, tofloat::Bool, symbolic_u0::Bool, u0_constructor::typeof(identity), guesses::Dict{…}, t::Float64, warn_initialize_determined::Bool, build_initializeprob::Bool, initialization_eqs::Vector{…}, fully_determined::Bool, check_units::Bool, kwargs::@Kwargs{…})
@ ModelingToolkit ~/.julia/packages/ModelingToolkit/K6okj/src/systems/diffeqs/abstractodesystem.jl:845
[13] process_DEProblem
@ ~/.julia/packages/ModelingToolkit/K6okj/src/systems/diffeqs/abstractodesystem.jl:766 [inlined]
[14] (ODEProblem{…})(sys::ODESystem, u0map::Vector{…}, tspan::Tuple{…}, parammap::Vector{…}; callback::Nothing, check_length::Bool, warn_initialize_determined::Bool, eval_expression::Bool, eval_module::Module, kwargs::@Kwargs{})
@ ModelingToolkit ~/.julia/packages/ModelingToolkit/K6okj/src/systems/diffeqs/abstractodesystem.jl:992
[15] (ODEProblem{…})(sys::ODESystem, u0map::Vector{…}, tspan::Tuple{…}, parammap::Vector{…})
@ ModelingToolkit ~/.julia/packages/ModelingToolkit/K6okj/src/systems/diffeqs/abstractodesystem.jl:980
[16] (ODEProblem{true})(::ODESystem, ::Vector{Pair{Num, Float64}}, ::Vararg{Any}; kwargs::@Kwargs{})
@ ModelingToolkit ~/.julia/packages/ModelingToolkit/K6okj/src/systems/diffeqs/abstractodesystem.jl:967
[17] (ODEProblem{true})(::ODESystem, ::Vector{Pair{Num, Float64}}, ::Vararg{Any})
@ ModelingToolkit ~/.julia/packages/ModelingToolkit/K6okj/src/systems/diffeqs/abstractodesystem.jl:966
[18] ODEProblem(::ODESystem, ::Vector{Pair{Num, Float64}}, ::Vararg{Any}; kwargs::@Kwargs{})
@ ModelingToolkit ~/.julia/packages/ModelingToolkit/K6okj/src/systems/diffeqs/abstractodesystem.jl:956
[19] ODEProblem(::ODESystem, ::Vector{Pair{Num, Float64}}, ::Vararg{Any})
@ ModelingToolkit ~/.julia/packages/ModelingToolkit/K6okj/src/systems/diffeqs/abstractodesystem.jl:955
[20] x_at_0(θ::Vector{ForwardDiff.Dual{ForwardDiff.Tag{typeof(x_at_0), Float64}, Float64, 2}})
@ Main ~/.julia/dev/SymBoltz/bug.jl:46
[21] vector_mode_dual_eval!
@ ~/.julia/packages/ForwardDiff/PcZ48/src/apiutils.jl:24 [inlined]
[22] vector_mode_gradient(f::typeof(x_at_0), x::Vector{…}, cfg::ForwardDiff.GradientConfig{…})
@ ForwardDiff ~/.julia/packages/ForwardDiff/PcZ48/src/gradient.jl:89
[23] gradient(f::Function, x::Vector{…}, cfg::ForwardDiff.GradientConfig{…}, ::Val{…})
@ ForwardDiff ~/.julia/packages/ForwardDiff/PcZ48/src/gradient.jl:19
[24] gradient(f::Function, x::Vector{Float64}, cfg::ForwardDiff.GradientConfig{ForwardDiff.Tag{…}, Float64, 2, Vector{…}})
@ ForwardDiff ~/.julia/packages/ForwardDiff/PcZ48/src/gradient.jl:17
[25] top-level scope
@ ~/.julia/dev/SymBoltz/bug.jl:50
in expression starting at /home/hermasl/.julia/dev/SymBoltz/bug.jl:50Strangely, if I change mh => 123.4 to mh => 123.3, the example runs as expected. Many other tiny tweaks also make it run.
Are you able to reproduce this? What could cause this?