# Issue with Differential Equation Solver

**URL:** <https://discourse.julialang.org/t/issue-with-differential-equation-solver/105008>\
**Category:** General Usage\
**Tags:** question, package, diffeq\
**Created:** [October 16, 2023, 11:05am UTC](https://discourse.julialang.org/t/issue-with-differential-equation-solver/105008 "2023-10-16T11:05:37Z")\
**Posts on this page:** 20\
**Page:** 1

<div class="post-metadata">

**Author:** ![A\_09](https://avatars.discourse-cdn.com/v4/letter/a/f1d935/32.png) [@A\_09](https://discourse.julialang.org/u/A_09)\
**Post date:** [October 16, 2023, 11:05am UTC](https://discourse.julialang.org/t/issue-with-differential-equation-solver/105008/1 "2023-10-16T11:05:39Z")

</div>

For this code:

begin

# Parameters, variables, and derivatives

`@parameters t x `@variables T(..)  
Dt = Differential(t)  
Dx = Differential(x)  
Dxx = Differential(x)^2

# MOL Discretization parameters

x\_max = L  
x\_min = 0  
nc = 20  
t\_min = 0 # Experiment 28  
t\_max = 6000 # Experiment 28

x\_num = range(x\_min, x\_max, length = nc)  
dx = (x\_max - x\_min) / (nc - 1)

eq = V\*Dx(T(t, x)) + Dt(T(t, x)) ~ 0

bcs = [T(t\_min, x) ~ Ts,  
- ks \* Dx(T(t, x\_max)) ~ 0,  
- ks \* Dx(T(t, x\_min)) ~ (- ϵ \* σ \* ((T(t, x\_min)^4))) + Q - h \* (T(t,x\_min) - Ts) - 91.64]

# Space and time domain

domains = [t ∈ Interval(t\_min, t\_max),  
x ∈ Interval(x\_min, x\_max)]

# Defining the PDE system

`@named pdesys = PDESystem([eq], bcs, domains, [t, x], [T(t, x)])

# Solving using MOL

order = 2  
discretization = MOLFiniteDifference([x =\> dx], t, approx\_order = order)

# Convert the PDE problem into an ODE problem

prob = discretize(pdesys, discretization)

# Solve ODE problem

sol = solve(prob, saveat = 3)  
T\_exp = sol.u[T(t, x)]

md"“”

## Numerical Solution

“”"  
end`

I am getting this error:

`MethodError: no method matching SciMLBase.PDETimeSeriesSolution(::SciMLBase.PDETimeSeriesSolution{Float64, 1, Dict{Symbolics.Num, Matrix{Float64}}, MethodOfLines.MOLMetadata{Val{true}(), MethodOfLines.DiscreteSpace{1, 1, MethodOfLines.CenterAlignedGrid}, MethodOfLines.MOLFiniteDifference{MethodOfLines.CenterAlignedGrid, MethodOfLines.ScalarizedDiscretization}, ModelingToolkit.PDESystem, Base.RefValue{Any}, MethodOfLines.ScalarizedDiscretization}, SciMLBase.ODESolution{Float64, 2, Vector{Vector{Float64}}, Nothing, Nothing, Vector{Float64}, Vector{Vector{Vector{Float64}}}, SciMLBase.ODEProblem{Vector{Float64}, Tuple{Float64, Float64}, true, Vector{Float64}, SciMLBase.ODEFunction{true, SciMLBase.AutoSpecialize, ModelingToolkit.var"#k#545"{RuntimeGeneratedFunctions.RuntimeGeneratedFunction{(:ˍ₋arg1, :ˍ₋arg2, :t), ModelingToolkit.var"#\_RGF\_ModTag", ModelingToolkit.var"#\_RGF\_ModTag", (0xe5c93a32, 0x2cbe7883, 0x421b7a96, 0x66e7a7df, 0xc00fbc62), Nothing}, RuntimeGeneratedFunctions.RuntimeGeneratedFunction{(:ˍ₋out, :ˍ₋arg1, :ˍ₋arg2, :t), ModelingToolkit.var"#\_RGF\_ModTag", ModelingToolkit.var"#\_RGF\_ModTag", (0xa72d68a9, 0xa06a2668, 0xbf287d64, 0x6dfb1292, 0xdc5dd793), Nothing}}, Matrix{Float64}, Nothing, Nothing, Nothing, Nothing, Nothing, Nothing, Nothing, Nothing, Nothing, Nothing, Nothing, Vector{Symbol}, Symbol, Vector{Any}, ModelingToolkit.var"#607#generated\_observed#555"{Bool, ModelingToolkit.ODESystem, Dict{Any, Any}, Vector{Any}}, Nothing, ModelingToolkit.ODESystem}, Base.Pairs{Symbol, Union{}, Tuple{}, NamedTuple{(), Tuple{}}}, MethodOfLines.MOLMetadata{Val{true}(), MethodOfLines.DiscreteSpace{1, 1, MethodOfLines.CenterAlignedGrid}, MethodOfLines.MOLFiniteDifference{MethodOfLines.CenterAlignedGrid, MethodOfLines.ScalarizedDiscretization}, ModelingToolkit.PDESystem, Base.RefValue{Any}, MethodOfLines.ScalarizedDiscretization}}, OrdinaryDiffEq.Rodas5P{1, false, LinearSolve.DefaultLinearSolver, typeof(OrdinaryDiffEq.DEFAULT\_PRECS), Val{:forward}, true, nothing}, OrdinaryDiffEq.InterpolationData{SciMLBase.ODEFunction{true, SciMLBase.AutoSpecialize, ModelingToolkit.var"#k#545"{RuntimeGeneratedFunctions.RuntimeGeneratedFunction{(:ˍ₋arg1, :ˍ₋arg2, :t), ModelingToolkit.var"#\_RGF\_ModTag", ModelingToolkit.var"#\_RGF\_ModTag", (0xe5c93a32, 0x2cbe7883, 0x421b7a96, 0x66e7a7df, 0xc00fbc62), Nothing}, RuntimeGeneratedFunctions.RuntimeGeneratedFunction{(:ˍ₋out, :ˍ₋arg1, :ˍ₋arg2, :t), ModelingToolkit.var"#\_RGF\_ModTag", ModelingToolkit.var"#\_RGF\_ModTag", (0xa72d68a9, 0xa06a2668, 0xbf287d64, 0x6dfb1292, 0xdc5dd793), Nothing}}, Matrix{Float64}, Nothing, Nothing, Nothing, Nothing, Nothing, Nothing, Nothing, Nothing, Nothing, Nothing, Nothing, Vector{Symbol}, Symbol, Vector{Any}, ModelingToolkit.var"#607#generated\_observed#555"{Bool, ModelingToolkit.ODESystem, Dict{Any, Any}, Vector{Any}}, Nothing, ModelingToolkit.ODESystem}, Vector{Vector{Float64}}, Vector{Float64}, Vector{Vector{Vector{Float64}}}, OrdinaryDiffEq.Rosenbrock5Cache{Vector{Float64}, Vector{Float64}, Vector{Float64}, Matrix{Float64}, Matrix{Float64}, OrdinaryDiffEq.Rodas5Tableau{Float64, Float64}, SciMLBase.TimeGradientWrapper{SciMLBase.ODEFunction{true, SciMLBase.AutoSpecialize, ModelingToolkit.var"#k#545"{RuntimeGeneratedFunctions.RuntimeGeneratedFunction{(:ˍ₋arg1, :ˍ₋arg2, :t), ModelingToolkit.var"#\_RGF\_ModTag", ModelingToolkit.var"#\_RGF\_ModTag", (0xe5c93a32, 0x2cbe7883, 0x421b7a96, 0x66e7a7df, 0xc00fbc62), Nothing}, RuntimeGeneratedFunctions.RuntimeGeneratedFunction{(:ˍ₋out, :ˍ₋arg1, :ˍ₋arg2, :t), ModelingToolkit.var"#\_RGF\_ModTag", ModelingToolkit.var"#\_RGF\_ModTag", (0xa72d68a9, 0xa06a2668, 0xbf287d64, 0x6dfb1292, 0xdc5dd793), Nothing}}, Matrix{Float64}, Nothing, Nothing, Nothing, Nothing, Nothing, Nothing, Nothing, Nothing, Nothing, Nothing, Nothing, Vector{Symbol}, Symbol, Vector{Any}, ModelingToolkit.var"#607#generated\_observed#555"{Bool, ModelingToolkit.ODESystem, Dict{Any, Any}, Vector{Any}}, Nothing, ModelingToolkit.ODESystem}, Vector{Float64}, Vector{Float64}}, SciMLBase.UJacobianWrapper{SciMLBase.ODEFunction{true, SciMLBase.AutoSpecialize, ModelingToolkit.var"#k#545"{RuntimeGeneratedFunctions.RuntimeGeneratedFunction{(:ˍ₋arg1, :ˍ₋arg2, :t), ModelingToolkit.var"#\_RGF\_ModTag", ModelingToolkit.var"#\_RGF\_ModTag", (0xe5c93a32, 0x2cbe7883, 0x421b7a96, 0x66e7a7df, 0xc00fbc62), Nothing}, RuntimeGeneratedFunctions.RuntimeGeneratedFunction{(:ˍ₋out, :ˍ₋arg1, :ˍ₋arg2, :t), ModelingToolkit.var"#\_RGF\_ModTag", ModelingToolkit.var"#\_RGF\_ModTag", (0xa72d68a9, 0xa06a2668, 0xbf287d64, 0x6dfb1292, 0xdc5dd793), Nothing}}, Matrix{Float64}, Nothing, Nothing, Nothing, Nothing, Nothing, Nothing, Nothing, Nothing, Nothing, Nothing, Nothing, Vector{Symbol}, Symbol, Vector{Any}, ModelingToolkit.var"#607#generated\_observed#555"{Bool, ModelingToolkit.ODESystem, Dict{Any, Any}, Vector{Any}}, Nothing, ModelingToolkit.ODESystem}, Float64, Vector{Float64}}, LinearSolve.LinearCache{Matrix{Float64}, Vector{Float64}, Vector{Float64}, SciMLBase.NullParameters, LinearSolve.DefaultLinearSolver, LinearSolve.DefaultLinearSolverInit{LinearAlgebra.LU{Float64, Matrix{Float64}, Vector{Int64}}, LinearAlgebra.QRCompactWY{Float64, Matrix{Float64}, Matrix{Float64}}, Nothing, Nothing, Nothing, Nothing, Nothing, Nothing, LinearAlgebra.LU{Float64, Matrix{Float64}, Vector{Int64}}, Tuple{LinearAlgebra.LU{Float64, Matrix{Float64}, Vector{Int64}}, Vector{Int64}}, Nothing, Nothing, Nothing, LinearAlgebra.SVD{Float64, Float64, Matrix{Float64}, Vector{Float64}}, LinearAlgebra.Cholesky{Float64, Matrix{Float64}}, LinearAlgebra.Cholesky{Float64, Matrix{Float64}}}, LinearSolve.InvPreconditioner{LinearAlgebra.Diagonal{Float64, Vector{Float64}}}, LinearAlgebra.Diagonal{Float64, Vector{Float64}}, Float64, Bool}, FiniteDiff.JacobianCache{Vector{Float64}, Vector{Float64}, Vector{Float64}, Vector{Float64}, UnitRange{Int64}, Nothing, Val{:forward}(), Float64}, FiniteDiff.GradientCache{Nothing, Vector{Float64}, Vector{Float64}, Float64, Val{:forward}(), Float64, Val{true}()}, Float64, OrdinaryDiffEq.Rodas5P{1, false, LinearSolve.DefaultLinearSolver, typeof(OrdinaryDiffEq.DEFAULT\_PRECS), Val{:forward}, true, nothing}}}, DiffEqBase.Stats, Nothing}, Nothing, Vector{Float64}, Tuple{Vector{Float64}, StepRangeLen{Float64, Base.TwicePrecision{Float64}, Base.TwicePrecision{Float64}, Int64}}, Vector{SymbolicUtils.BasicSymbolic{Real}}, Vector{Symbolics.Num}, SciMLBase.ODEProblem{Vector{Float64}, Tuple{Float64, Float64}, true, Vector{Float64}, SciMLBase.ODEFunction{true, SciMLBase.AutoSpecialize, ModelingToolkit.var"#k#545"{RuntimeGeneratedFunctions.RuntimeGeneratedFunction{(:ˍ₋arg1, :ˍ₋arg2, :t), ModelingToolkit.var"#\_RGF\_ModTag", ModelingToolkit.var"#\_RGF\_ModTag", (0xe5c93a32, 0x2cbe7883, 0x421b7a96, 0x66e7a7df, 0xc00fbc62), Nothing}, RuntimeGeneratedFunctions.RuntimeGeneratedFunction{(:ˍ₋out, :ˍ₋arg1, :ˍ₋arg2, :t), ModelingToolkit.var"#\_RGF\_ModTag", ModelingToolkit.var"#\_RGF\_ModTag", (0xa72d68a9, 0xa06a2668, 0xbf287d64, 0x6dfb1292, 0xdc5dd793), Nothing}}, Matrix{Float64}, Nothing, Nothing, Nothing, Nothing, Nothing, Nothing, Nothing, Nothing, Nothing, Nothing, Nothing, Vector{Symbol}, Symbol, Vector{Any}, ModelingToolkit.var"#607#generated\_observed#555"{Bool, ModelingToolkit.ODESystem, Dict{Any, Any}, Vector{Any}}, Nothing, ModelingToolkit.ODESystem}, Base.Pairs{Symbol, Union{}, Tuple{}, NamedTuple{(), Tuple{}}}, MethodOfLines.MOLMetadata{Val{true}(), MethodOfLines.DiscreteSpace{1, 1, MethodOfLines.CenterAlignedGrid}, MethodOfLines.MOLFiniteDifference{MethodOfLines.CenterAlignedGrid, MethodOfLines.ScalarizedDiscretization}, ModelingToolkit.PDESystem, Base.RefValue{Any}, MethodOfLines.ScalarizedDiscretization}}, OrdinaryDiffEq.Rodas5P{1, false, LinearSolve.DefaultLinearSolver, typeof(OrdinaryDiffEq.DEFAULT\_PRECS), Val{:forward}, true, nothing}, Dict{Symbolics.Num, Interpolations.GriddedInterpolation{Float64, 2, Matrix{Float64}, Interpolations.Gridded{Interpolations.Linear{Interpolations.Throw{Interpolations.OnGrid}}}, Tuple{Vector{Float64}, Vector{Float64}}}}, DiffEqBase.Stats}, ::MethodOfLines.MOLMetadata{Val{true}(), MethodOfLines.DiscreteSpace{1, 1, MethodOfLines.CenterAlignedGrid}, MethodOfLines.MOLFiniteDifference{MethodOfLines.CenterAlignedGrid, MethodOfLines.ScalarizedDiscretization}, ModelingToolkit.PDESystem, Base.RefValue{Any}, MethodOfLines.ScalarizedDiscretization})

Closest candidates are:

SciMLBase.PDETimeSeriesSolution(!Matched::SciMLBase.AbstractODESolution{T}, ::MethodOfLines.MOLMetadata) where T at ~/.julia/packages/MethodOfLines/uGynQ/src/interface/solution/timedep.jl:2

1. **wrap\_sol** (::SciMLBase.PDETimeSeriesSolution{Float64, 1, Dict{Symbolics.Num, Matrix{Float64}}, MethodOfLines.MOLMetadata{Val{true}(), MethodOfLines.DiscreteSpace{1, 1, MethodOfLines.CenterAlignedGrid}, MethodOfLines.MOLFiniteDifference{MethodOfLines.CenterAlignedGrid, MethodOfLines.ScalarizedDiscretization}, ModelingToolkit.PDESystem, Base.RefValue{Any}, MethodOfLines.ScalarizedDiscretization}, SciMLBase.ODESolution{Float64, 2, Vector{Vector{Float64}}, Nothing, Nothing, Vector{Float64}, Vector{Vector{Vector{Float64}}}, SciMLBase.ODEProblem{Vector{Float64}, Tuple{Float64, Float64}, true, Vector{Float64}, SciMLBase.ODEFunction{true, SciMLBase.AutoSpecialize, ModelingToolkit.var"#k#545"{RuntimeGeneratedFunctions.RuntimeGeneratedFunction{(:ˍ₋arg1, :ˍ₋arg2, :t), ModelingToolkit.var"#\_RGF\_ModTag", ModelingToolkit.var"#\_RGF\_ModTag", (0xe5c93a32, 0x2cbe7883, 0x421b7a96, 0x66e7a7df, 0xc00fbc62), Nothing}, RuntimeGeneratedFunctions.RuntimeGeneratedFunction{(:ˍ₋out, :ˍ₋arg1, :ˍ₋arg2, :t), ModelingToolkit.var"#\_RGF\_ModTag", ModelingToolkit.var"#\_RGF\_ModTag", (0xa72d68a9, 0xa06a2668, 0xbf287d64, 0x6dfb1292, 0xdc5dd793), Nothing}}, Matrix{Float64}, Nothing, Nothing, Nothing, Nothing, Nothing, Nothing, Nothing, Nothing, Nothing, Nothing, Nothing, Vector{Symbol}, Symbol, Vector{Any}, ModelingToolkit.var"#607#generated\_observed#555"{Bool, ModelingToolkit.ODESystem, Dict{Any, Any}, Vector{Any}}, Nothing, ModelingToolkit.ODESystem}, Base.Pairs{Symbol, Union{}, Tuple{}, NamedTuple{(), Tuple{}}}, MethodOfLines.MOLMetadata{Val{true}(), MethodOfLines.DiscreteSpace{1, 1, MethodOfLines.CenterAlignedGrid}, MethodOfLines.MOLFiniteDifference{MethodOfLines.CenterAlignedGrid, MethodOfLines.ScalarizedDiscretization}, ModelingToolkit.PDESystem, Base.RefValue{Any}, MethodOfLines.ScalarizedDiscretization}}, OrdinaryDiffEq.Rodas5P{1, false, LinearSolve.DefaultLinearSolver, typeof(OrdinaryDiffEq.DEFAULT\_PRECS), Val{:forward}, true, nothing}, OrdinaryDiffEq.InterpolationData{SciMLBase.ODEFunction{true, SciMLBase.AutoSpecialize, ModelingToolkit.var"#k#545"{RuntimeGeneratedFunctions.RuntimeGeneratedFunction{(:ˍ₋arg1, :ˍ₋arg2, :t), ModelingToolkit.var"#\_RGF\_ModTag", ModelingToolkit.var"#\_RGF\_ModTag", (0xe5c93a32, 0x2cbe7883, 0x421b7a96, 0x66e7a7df, 0xc00fbc62), Nothing}, RuntimeGeneratedFunctions.RuntimeGeneratedFunction{(:ˍ₋out, :ˍ₋arg1, :ˍ₋arg2, :t), ModelingToolkit.var"#\_RGF\_ModTag", ModelingToolkit.var"#\_RGF\_ModTag", (0xa72d68a9, 0xa06a2668, 0xbf287d64, 0x6dfb1292, 0xdc5dd793), Nothing}}, Matrix{Float64}, Nothing, Nothing, Nothing, Nothing, Nothing, Nothing, Nothing, Nothing, Nothing, Nothing, Nothing, Vector{Symbol}, Symbol, Vector{Any}, ModelingToolkit.var"#607#generated\_observed#555"{Bool, ModelingToolkit.ODESystem, Dict{Any, Any}, Vector{Any}}, Nothing, ModelingToolkit.ODESystem}, Vector{Vector{Float64}}, Vector{Float64}, Vector{Vector{Vector{Float64}}}, OrdinaryDiffEq.Rosenbrock5Cache{Vector{Float64}, Vector{Float64}, Vector{Float64}, Matrix{Float64}, Matrix{Float64}, OrdinaryDiffEq.Rodas5Tableau{Float64, Float64}, SciMLBase.TimeGradientWrapper{SciMLBase.ODEFunction{true, SciMLBase.AutoSpecialize, ModelingToolkit.var"#k#545"{RuntimeGeneratedFunctions.RuntimeGeneratedFunction{(:ˍ₋arg1, :ˍ₋arg2, :t), ModelingToolkit.var"#\_RGF\_ModTag", ModelingToolkit.var"#\_RGF\_ModTag", (0xe5c93a32, 0x2cbe7883, 0x421b7a96, 0x66e7a7df, 0xc00fbc62), Nothing}, RuntimeGeneratedFunctions.RuntimeGeneratedFunction{(:ˍ₋out, :ˍ₋arg1, :ˍ₋arg2, :t), ModelingToolkit.var"#\_RGF\_ModTag", ModelingToolkit.var"#\_RGF\_ModTag", (0xa72d68a9, 0xa06a2668, 0xbf287d64, 0x6dfb1292, 0xdc5dd793), Nothing}}, Matrix{Float64}, Nothing, Nothing, Nothing, Nothing, Nothing, Nothing, Nothing, Nothing, Nothing, Nothing, Nothing, Vector{Symbol}, Symbol, Vector{Any}, ModelingToolkit.var"#607#generated\_observed#555"{Bool, ModelingToolkit.ODESystem, Dict{Any, Any}, Vector{Any}}, Nothing, ModelingToolkit.ODESystem}, Vector{Float64}, Vector{Float64}}, SciMLBase.UJacobianWrapper{SciMLBase.ODEFunction{true, SciMLBase.AutoSpecialize, ModelingToolkit.var"#k#545"{RuntimeGeneratedFunctions.RuntimeGeneratedFunction{(:ˍ₋arg1, :ˍ₋arg2, :t), ModelingToolkit.var"#\_RGF\_ModTag", ModelingToolkit.var"#\_RGF\_ModTag", (0xe5c93a32, 0x2cbe7883, 0x421b7a96, 0x66e7a7df, 0xc00fbc62), Nothing}, RuntimeGeneratedFunctions.RuntimeGeneratedFunction{(:ˍ₋out, :ˍ₋arg1, :ˍ₋arg2, :t), ModelingToolkit.var"#\_RGF\_ModTag", ModelingToolkit.var"#\_RGF\_ModTag", (0xa72d68a9, 0xa06a2668, 0xbf287d64, 0x6dfb1292, 0xdc5dd793), Nothing}}, Matrix{Float64}, Nothing, Nothing, Nothing, Nothing, Nothing, Nothing, Nothing, Nothing, Nothing, Nothing, Nothing, Vector{Symbol}, Symbol, Vector{Any}, ModelingToolkit.var"#607#generated\_observed#555"{Bool, ModelingToolkit.ODESystem, Dict{Any, Any}, Vector{Any}}, Nothing, ModelingToolkit.ODESystem}, Float64, Vector{Float64}}, LinearSolve.LinearCache{Matrix{Float64}, Vector{Float64}, Vector{Float64}, SciMLBase.NullParameters, LinearSolve.DefaultLinearSolver, LinearSolve.DefaultLinearSolverInit{LinearAlgebra.LU{Float64, Matrix{Float64}, Vector{Int64}}, LinearAlgebra.QRCompactWY{Float64, Matrix{Float64}, Matrix{Float64}}, Nothing, Nothing, Nothing, Nothing, Nothing, Nothing, LinearAlgebra.LU{Float64, Matrix{Float64}, Vector{Int64}}, Tuple{LinearAlgebra.LU{Float64, Matrix{Float64}, Vector{Int64}}, Vector{Int64}}, Nothing, Nothing, Nothing, LinearAlgebra.SVD{Float64, Float64, Matrix{Float64}, Vector{Float64}}, LinearAlgebra.Cholesky{Float64, Matrix{Float64}}, LinearAlgebra.Cholesky{Float64, Matrix{Float64}}}, LinearSolve.InvPreconditioner{LinearAlgebra.Diagonal{Float64, Vector{Float64}}}, LinearAlgebra.Diagonal{Float64, Vector{Float64}}, Float64, Bool}, FiniteDiff.JacobianCache{Vector{Float64}, Vector{Float64}, Vector{Float64}, Vector{Float64}, UnitRange{Int64}, Nothing, Val{:forward}(), Float64}, FiniteDiff.GradientCache{Nothing, Vector{Float64}, Vector{Float64}, Float64, Val{:forward}(), Float64, Val{true}()}, Float64, OrdinaryDiffEq.Rodas5P{1, false, LinearSolve.DefaultLinearSolver, typeof(OrdinaryDiffEq.DEFAULT\_PRECS), Val{:forward}, true, nothing}}}, DiffEqBase.Stats, Nothing}, Nothing, Vector{Float64}, Tuple{Vector{Float64}, StepRangeLen{Float64, Base.TwicePrecision{Float64}, Base.TwicePrecision{Float64}, Int64}}, Vector{SymbolicUtils.BasicSymbolic{Real}}, Vector{Symbolics.Num}, SciMLBase.ODEProblem{Vector{Float64}, Tuple{Float64, Float64}, true, Vector{Float64}, SciMLBase.ODEFunction{true, SciMLBase.AutoSpecialize, ModelingToolkit.var"#k#545"{RuntimeGeneratedFunctions.RuntimeGeneratedFunction{(:ˍ₋arg1, :ˍ₋arg2, :t), ModelingToolkit.var"#\_RGF\_ModTag", ModelingToolkit.var"#\_RGF\_ModTag", (0xe5c93a32, 0x2cbe7883, 0x421b7a96, 0x66e7a7df, 0xc00fbc62), Nothing}, RuntimeGeneratedFunctions.RuntimeGeneratedFunction{(:ˍ₋out, :ˍ₋arg1, :ˍ₋arg2, :t), ModelingToolkit.var"#\_RGF\_ModTag", ModelingToolkit.var"#\_RGF\_ModTag", (0xa72d68a9, 0xa06a2668, 0xbf287d64, 0x6dfb1292, 0xdc5dd793), Nothing}}, Matrix{Float64}, Nothing, Nothing, Nothing, Nothing, Nothing, Nothing, Nothing, Nothing, Nothing, Nothing, Nothing, Vector{Symbol}, Symbol, Vector{Any}, ModelingToolkit.var"#607#generated\_observed#555"{Bool, ModelingToolkit.ODESystem, Dict{Any, Any}, Vector{Any}}, Nothing, ModelingToolkit.ODESystem}, Base.Pairs{Symbol, Union{}, Tuple{}, NamedTuple{(), Tuple{}}}, MethodOfLines.MOLMetadata{Val{true}(), MethodOfLines.DiscreteSpace{1, 1, MethodOfLines.CenterAlignedGrid}, MethodOfLines.MOLFiniteDifference{MethodOfLines.CenterAlignedGrid, MethodOfLines.ScalarizedDiscretization}, ModelingToolkit.PDESystem, Base.RefValue{Any}, MethodOfLines.ScalarizedDiscretization}}, OrdinaryDiffEq.Rodas5P{1, false, LinearSolve.DefaultLinearSolver, typeof(OrdinaryDiffEq.DEFAULT\_PRECS), Val{:forward}, true, nothing}, Dict{Symbolics.Num, Interpolations.GriddedInterpolation{Float64, 2, Matrix{Float64}, Interpolations.Gridded{Interpolations.Linear{Interpolations.Throw{Interpolations.OnGrid}}}, Tuple{Vector{Float64}, Vector{Float64}}}}, DiffEqBase.Stats}, ::MethodOfLines.MOLMetadata{Val{true}(), MethodOfLines.DiscreteSpace{1, 1, MethodOfLines.CenterAlignedGrid}, MethodOfLines.MOLFiniteDifference{MethodOfLines.CenterAlignedGrid, MethodOfLines.ScalarizedDiscretization}, ModelingToolkit.PDESystem, Base.RefValue{Any}, MethodOfLines.ScalarizedDiscretization})@_pde\_solutions.jl:119_
2. **wrap\_sol** (::SciMLBase.PDETimeSeriesSolution{Float64, 1, Dict{Symbolics.Num, Matrix{Float64}}, MethodOfLines.MOLMetadata{Val{true}(), MethodOfLines.DiscreteSpace{1, 1, MethodOfLines.CenterAlignedGrid}, MethodOfLines.MOLFiniteDifference{MethodOfLines.CenterAlignedGrid, MethodOfLines.ScalarizedDiscretization}, ModelingToolkit.PDESystem, Base.RefValue{Any}, MethodOfLines.ScalarizedDiscretization}, SciMLBase.ODESolution{Float64, 2, Vector{Vector{Float64}}, Nothing, Nothing, Vector{Float64}, Vector{Vector{Vector{Float64}}}, SciMLBase.ODEProblem{Vector{Float64}, Tuple{Float64, Float64}, true, Vector{Float64}, SciMLBase.ODEFunction{true, SciMLBase.AutoSpecialize, ModelingToolkit.var"#k#545"{RuntimeGeneratedFunctions.RuntimeGeneratedFunction{(:ˍ₋arg1, :ˍ₋arg2, :t), ModelingToolkit.var"#\_RGF\_ModTag", ModelingToolkit.var"#\_RGF\_ModTag", (0xe5c93a32, 0x2cbe7883, 0x421b7a96, 0x66e7a7df, 0xc00fbc62), Nothing}, RuntimeGeneratedFunctions.RuntimeGeneratedFunction{(:ˍ₋out, :ˍ₋arg1, :ˍ₋arg2, :t), ModelingToolkit.var"#\_RGF\_ModTag", ModelingToolkit.var"#\_RGF\_ModTag", (0xa72d68a9, 0xa06a2668, 0xbf287d64, 0x6dfb1292, 0xdc5dd793), Nothing}}, Matrix{Float64}, Nothing, Nothing, Nothing, Nothing, Nothing, Nothing, Nothing, Nothing, Nothing, Nothing, Nothing, Vector{Symbol}, Symbol, Vector{Any}, ModelingToolkit.var"#607#generated\_observed#555"{Bool, ModelingToolkit.ODESystem, Dict{Any, Any}, Vector{Any}}, Nothing, ModelingToolkit.ODESystem}, Base.Pairs{Symbol, Union{}, Tuple{}, NamedTuple{(), Tuple{}}}, MethodOfLines.MOLMetadata{Val{true}(), MethodOfLines.DiscreteSpace{1, 1, MethodOfLines.CenterAlignedGrid}, MethodOfLines.MOLFiniteDifference{MethodOfLines.CenterAlignedGrid, MethodOfLines.ScalarizedDiscretization}, ModelingToolkit.PDESystem, Base.RefValue{Any}, MethodOfLines.ScalarizedDiscretization}}, OrdinaryDiffEq.Rodas5P{1, false, LinearSolve.DefaultLinearSolver, typeof(OrdinaryDiffEq.DEFAULT\_PRECS), Val{:forward}, true, nothing}, OrdinaryDiffEq.InterpolationData{SciMLBase.ODEFunction{true, SciMLBase.AutoSpecialize, ModelingToolkit.var"#k#545"{RuntimeGeneratedFunctions.RuntimeGeneratedFunction{(:ˍ₋arg1, :ˍ₋arg2, :t), ModelingToolkit.var"#\_RGF\_ModTag", ModelingToolkit.var"#\_RGF\_ModTag", (0xe5c93a32, 0x2cbe7883, 0x421b7a96, 0x66e7a7df, 0xc00fbc62), Nothing}, RuntimeGeneratedFunctions.RuntimeGeneratedFunction{(:ˍ₋out, :ˍ₋arg1, :ˍ₋arg2, :t), ModelingToolkit.var"#\_RGF\_ModTag", ModelingToolkit.var"#\_RGF\_ModTag", (0xa72d68a9, 0xa06a2668, 0xbf287d64, 0x6dfb1292, 0xdc5dd793), Nothing}}, Matrix{Float64}, Nothing, Nothing, Nothing, Nothing, Nothing, Nothing, Nothing, Nothing, Nothing, Nothing, Nothing, Vector{Symbol}, Symbol, Vector{Any}, ModelingToolkit.var"#607#generated\_observed#555"{Bool, ModelingToolkit.ODESystem, Dict{Any, Any}, Vector{Any}}, Nothing, ModelingToolkit.ODESystem}, Vector{Vector{Float64}}, Vector{Float64}, Vector{Vector{Vector{Float64}}}, OrdinaryDiffEq.Rosenbrock5Cache{Vector{Float64}, Vector{Float64}, Vector{Float64}, Matrix{Float64}, Matrix{Float64}, OrdinaryDiffEq.Rodas5Tableau{Float64, Float64}, SciMLBase.TimeGradientWrapper{SciMLBase.ODEFunction{true, SciMLBase.AutoSpecialize, ModelingToolkit.var"#k#545"{RuntimeGeneratedFunctions.RuntimeGeneratedFunction{(:ˍ₋arg1, :ˍ₋arg2, :t), ModelingToolkit.var"#\_RGF\_ModTag", ModelingToolkit.var"#\_RGF\_ModTag", (0xe5c93a32, 0x2cbe7883, 0x421b7a96, 0x66e7a7df, 0xc00fbc62), Nothing}, RuntimeGeneratedFunctions.RuntimeGeneratedFunction{(:ˍ₋out, :ˍ₋arg1, :ˍ₋arg2, :t), ModelingToolkit.var"#\_RGF\_ModTag", ModelingToolkit.var"#\_RGF\_ModTag", (0xa72d68a9, 0xa06a2668, 0xbf287d64, 0x6dfb1292, 0xdc5dd793), Nothing}}, Matrix{Float64}, Nothing, Nothing, Nothing, Nothing, Nothing, Nothing, Nothing, Nothing, Nothing, Nothing, Nothing, Vector{Symbol}, Symbol, Vector{Any}, ModelingToolkit.var"#607#generated\_observed#555"{Bool, ModelingToolkit.ODESystem, Dict{Any, Any}, Vector{Any}}, Nothing, ModelingToolkit.ODESystem}, Vector{Float64}, Vector{Float64}}, SciMLBase.UJacobianWrapper{SciMLBase.ODEFunction{true, SciMLBase.AutoSpecialize, ModelingToolkit.var"#k#545"{RuntimeGeneratedFunctions.RuntimeGeneratedFunction{(:ˍ₋arg1, :ˍ₋arg2, :t), ModelingToolkit.var"#\_RGF\_ModTag", ModelingToolkit.var"#\_RGF\_ModTag", (0xe5c93a32, 0x2cbe7883, 0x421b7a96, 0x66e7a7df, 0xc00fbc62), Nothing}, RuntimeGeneratedFunctions.RuntimeGeneratedFunction{(:ˍ₋out, :ˍ₋arg1, :ˍ₋arg2, :t), ModelingToolkit.var"#\_RGF\_ModTag", ModelingToolkit.var"#\_RGF\_ModTag", (0xa72d68a9, 0xa06a2668, 0xbf287d64, 0x6dfb1292, 0xdc5dd793), Nothing}}, Matrix{Float64}, Nothing, Nothing, Nothing, Nothing, Nothing, Nothing, Nothing, Nothing, Nothing, Nothing, Nothing, Vector{Symbol}, Symbol, Vector{Any}, ModelingToolkit.var"#607#generated\_observed#555"{Bool, ModelingToolkit.ODESystem, Dict{Any, Any}, Vector{Any}}, Nothing, ModelingToolkit.ODESystem}, Float64, Vector{Float64}}, LinearSolve.LinearCache{Matrix{Float64}, Vector{Float64}, Vector{Float64}, SciMLBase.NullParameters, LinearSolve.DefaultLinearSolver, LinearSolve.DefaultLinearSolverInit{LinearAlgebra.LU{Float64, Matrix{Float64}, Vector{Int64}}, LinearAlgebra.QRCompactWY{Float64, Matrix{Float64}, Matrix{Float64}}, Nothing, Nothing, Nothing, Nothing, Nothing, Nothing, LinearAlgebra.LU{Float64, Matrix{Float64}, Vector{Int64}}, Tuple{LinearAlgebra.LU{Float64, Matrix{Float64}, Vector{Int64}}, Vector{Int64}}, Nothing, Nothing, Nothing, LinearAlgebra.SVD{Float64, Float64, Matrix{Float64}, Vector{Float64}}, LinearAlgebra.Cholesky{Float64, Matrix{Float64}}, LinearAlgebra.Cholesky{Float64, Matrix{Float64}}}, LinearSolve.InvPreconditioner{LinearAlgebra.Diagonal{Float64, Vector{Float64}}}, LinearAlgebra.Diagonal{Float64, Vector{Float64}}, Float64, Bool}, FiniteDiff.JacobianCache{Vector{Float64}, Vector{Float64}, Vector{Float64}, Vector{Float64}, UnitRange{Int64}, Nothing, Val{:forward}(), Float64}, FiniteDiff.GradientCache{Nothing, Vector{Float64}, Vector{Float64}, Float64, Val{:forward}(), Float64, Val{true}()}, Float64, OrdinaryDiffEq.Rodas5P{1, false, LinearSolve.DefaultLinearSolver, typeof(OrdinaryDiffEq.DEFAULT\_PRECS), Val{:forward}, true, nothing}}}, DiffEqBase.Stats, Nothing}, Nothing, Vector{Float64}, Tuple{Vector{Float64}, StepRangeLen{Float64, Base.TwicePrecision{Float64}, Base.TwicePrecision{Float64}, Int64}}, Vector{SymbolicUtils.BasicSymbolic{Real}}, Vector{Symbolics.Num}, SciMLBase.ODEProblem{Vector{Float64}, Tuple{Float64, Float64}, true, Vector{Float64}, SciMLBase.ODEFunction{true, SciMLBase.AutoSpecialize, ModelingToolkit.var"#k#545"{RuntimeGeneratedFunctions.RuntimeGeneratedFunction{(:ˍ₋arg1, :ˍ₋arg2, :t), ModelingToolkit.var"#\_RGF\_ModTag", ModelingToolkit.var"#\_RGF\_ModTag", (0xe5c93a32, 0x2cbe7883, 0x421b7a96, 0x66e7a7df, 0xc00fbc62), Nothing}, RuntimeGeneratedFunctions.RuntimeGeneratedFunction{(:ˍ₋out, :ˍ₋arg1, :ˍ₋arg2, :t), ModelingToolkit.var"#\_RGF\_ModTag", ModelingToolkit.var"#\_RGF\_ModTag", (0xa72d68a9, 0xa06a2668, 0xbf287d64, 0x6dfb1292, 0xdc5dd793), Nothing}}, Matrix{Float64}, Nothing, Nothing, Nothing, Nothing, Nothing, Nothing, Nothing, Nothing, Nothing, Nothing, Nothing, Vector{Symbol}, Symbol, Vector{Any}, ModelingToolkit.var"#607#generated\_observed#555"{Bool, ModelingToolkit.ODESystem, Dict{Any, Any}, Vector{Any}}, Nothing, ModelingToolkit.ODESystem}, Base.Pairs{Symbol, Union{}, Tuple{}, NamedTuple{(), Tuple{}}}, MethodOfLines.MOLMetadata{Val{true}(), MethodOfLines.DiscreteSpace{1, 1, MethodOfLines.CenterAlignedGrid}, MethodOfLines.MOLFiniteDifference{MethodOfLines.CenterAlignedGrid, MethodOfLines.ScalarizedDiscretization}, ModelingToolkit.PDESystem, Base.RefValue{Any}, MethodOfLines.ScalarizedDiscretization}}, OrdinaryDiffEq.Rodas5P{1, false, LinearSolve.DefaultLinearSolver, typeof(OrdinaryDiffEq.DEFAULT\_PRECS), Val{:forward}, true, nothing}, Dict{Symbolics.Num, Interpolations.GriddedInterpolation{Float64, 2, Matrix{Float64}, Interpolations.Gridded{Interpolations.Linear{Interpolations.Throw{Interpolations.OnGrid}}}, Tuple{Vector{Float64}, Vector{Float64}}}}, DiffEqBase.Stats})@_basic\_solutions.jl:98_
3. **var"#solve#40"** (::Nothing, ::Nothing, ::Nothing, ::Val{true}, ::Base.Pairs{Symbol, Int64, Tuple{Symbol}, NamedTuple{(:saveat,), Tuple{Int64}}}, ::typeof(CommonSolve.solve), ::SciMLBase.ODEProblem{Vector{Float64}, Tuple{Int64, Int64}, true, Vector{Float64}, SciMLBase.ODEFunction{true, SciMLBase.AutoSpecialize, ModelingToolkit.var"#k#545"{RuntimeGeneratedFunctions.RuntimeGeneratedFunction{(:ˍ₋arg1, :ˍ₋arg2, :t), ModelingToolkit.var"#\_RGF\_ModTag", ModelingToolkit.var"#\_RGF\_ModTag", (0xe5c93a32, 0x2cbe7883, 0x421b7a96, 0x66e7a7df, 0xc00fbc62), Nothing}, RuntimeGeneratedFunctions.RuntimeGeneratedFunction{(:ˍ₋out, :ˍ₋arg1, :ˍ₋arg2, :t), ModelingToolkit.var"#\_RGF\_ModTag", ModelingToolkit.var"#\_RGF\_ModTag", (0xa72d68a9, 0xa06a2668, 0xbf287d64, 0x6dfb1292, 0xdc5dd793), Nothing}}, Matrix{Float64}, Nothing, Nothing, Nothing, Nothing, Nothing, Nothing, Nothing, Nothing, Nothing, Nothing, Nothing, Vector{Symbol}, Symbol, Vector{Any}, ModelingToolkit.var"#607#generated\_observed#555"{Bool, ModelingToolkit.ODESystem, Dict{Any, Any}, Vector{Any}}, Nothing, ModelingToolkit.ODESystem}, Base.Pairs{Symbol, Union{}, Tuple{}, NamedTuple{(), Tuple{}}}, MethodOfLines.MOLMetadata{Val{true}(), MethodOfLines.DiscreteSpace{1, 1, MethodOfLines.CenterAlignedGrid}, MethodOfLines.MOLFiniteDifference{MethodOfLines.CenterAlignedGrid, MethodOfLines.ScalarizedDiscretization}, ModelingToolkit.PDESystem, Base.RefValue{Any}, MethodOfLines.ScalarizedDiscretization}})@_solve.jl:930_
4. **top-level scope** @_[Local: 41](http://localhost:1234/edit?id=06ed7d92-627c-11ee-1bff-a91b67f089e4#)_ [inlined]`

I have used this differential solver with for this code below and it works fine:  
`begin # Parameters, variables, and derivatives ` @parameters t x  
` @variables T(..)  
Dt = Differential(t)  
Dx = Differential(x)  
Dxx = Differential(x)^2

```
# MOL Discretization parameters
x_max = L 
x_min = 0

t_min = 0 # Experiment 28
t_max = 6737 # 6737 # Experiment 28

nc = 20
x_num = range(x_min, x_max, length=nc)
dx = (x_max - x_min) / (nc - 1)

eq = ((52000 * exp(-1.24e-5 * T(t, x)) / (T(t, x) + 437)) / 1000) * Dxx(T(t, x)) + I0 * exp(-2300 * T(t, x)) ~ ρs * Cps * Dt(T(t, x))

bcs = [T(t_min, x) ~ Ts,
    - ((52000 * exp(-1.24e-5 * T(t, x)) / (T(t, x) + 437)) / 1000) * Dx(T(t, x_max)) ~ 0,
    -((52000 * exp(-1.24e-5 * T(t, x)) / (T(t, x) + 437)) / 1000) * Dx(T(t, x_min)) ~ (-(ϵ * σ * ((T(t, x_min)^4) - (Ts)^4)) + Q)]

# Space and time domain
domains = [t ∈ Interval(t_min, t_max),
    x ∈ Interval(x_min, x_max)]

# Defining the PDE system
@named pdesys = PDESystem([eq], bcs, domains, [t, x], [T(t, x)])

# Solving using MOL
order = 2
discretization = MOLFiniteDifference([x => dx], t, approx_order=order)

# Convert the PDE problem into an ODE problem
prob = discretize(pdesys, discretization)
# Solve ODE problem
sol = solve(prob, saveat=3)
T_exp = sol.u[T(t, x)]

md"""
## Numerical Solution
"""

```

end`

I am unsure of how to address this error, would appreciate some help!

---

<div class="post-metadata">

**Author:** ![ChrisRackauckas](https://sea2.discourse-cdn.com/julialang/user_avatar/discourse.julialang.org/chrisrackauckas/32/77_2.png) [@ChrisRackauckas](https://discourse.julialang.org/u/ChrisRackauckas)\
**Post date:** [October 16, 2023, 11:40am UTC](https://discourse.julialang.org/t/issue-with-differential-equation-solver/105008/2 "2023-10-16T11:40:04Z")

</div>

What versions? Share `]st`

---

<div class="post-metadata">

**Author:** ![A\_09](https://avatars.discourse-cdn.com/v4/letter/a/f1d935/32.png) [@A\_09](https://discourse.julialang.org/u/A_09)\
**Post date:** [October 16, 2023, 11:47am UTC](https://discourse.julialang.org/t/issue-with-differential-equation-solver/105008/3 "2023-10-16T11:47:10Z")

</div>

The Julia version is 1.8

---

<div class="post-metadata">

**Author:** ![ChrisRackauckas](https://sea2.discourse-cdn.com/julialang/user_avatar/discourse.julialang.org/chrisrackauckas/32/77_2.png) [@ChrisRackauckas](https://discourse.julialang.org/u/ChrisRackauckas)\
**Post date:** [October 16, 2023, 12:05pm UTC](https://discourse.julialang.org/t/issue-with-differential-equation-solver/105008/4 "2023-10-16T12:05:49Z")

</div>

That’s not the full list of package versions.

---

<div class="post-metadata">

**Author:** ![A\_09](https://avatars.discourse-cdn.com/v4/letter/a/f1d935/32.png) [@A\_09](https://discourse.julialang.org/u/A_09)\
**Post date:** [October 16, 2023, 9:42pm UTC](https://discourse.julialang.org/t/issue-with-differential-equation-solver/105008/5 "2023-10-16T21:42:46Z")

</div>

**Status** `~/.julia/environments/v1.8/Project.toml`

⌃ [093aae92] BSplineKit v0.4.0

⌃ [336ed68f] CSV v0.10.9

⌃ [35d6a980] ColorSchemes v3.20.0

[2e2c70e5] DataFitting v0.1.0

⌃ [a93c6f00] DataFrames v1.3.6

⌃ [0c46a032] DifferentialEquations v6.18.0

[607db5a9] DifferentialEvolutionMCMC v0.7.6

⌅ [5b8099bc] DomainSets v0.5.15

⌃ [f6369f11] ForwardDiff v0.10.35

⌃ [34004b35] HypergeometricFunctions v0.3.15

⌃ [4345ca2d] Loess v0.5.4

⌅ [2fda8390] LsqFit v0.11.0

⌃ [961ee093] ModelingToolkit v8.1.0

[76087f3c] NLopt v1.0.0

⌅ [8913a72c] NonlinearSolve v0.3.22

⌃ [429524aa] Optim v1.7.4

⌃ [7f7a1694] Optimization v3.11.2

⌃ [36348300] OptimizationOptimJL v0.1.5

⌅ [1dea7af3] OrdinaryDiffEq v5.55.1

[58dd65bb] Plotly v0.4.1

⌃ [91a5bcdd] Plots v1.38.7

⌃ [c3e4b0f8] Pluto v0.19.9

⌃ [7f904dfe] PlutoUI v0.7.50

⌃ [f3b207a7] StatsPlots v0.15.1

⌃ [24249f21] SymPy v1.1.12

⌃ [fdbf4ff8] XLSX v0.9.0

[b77e0a4c] InteractiveUtils

[10745b16] Statistics

**Info** Packages marked with ⌃ and ⌅ have new versions available, but those with ⌅ are restricted by compatibility constraints from upgrading. To see why use `status --outdated`

---

<div class="post-metadata">

**Author:** ![Zentrik](https://sea2.discourse-cdn.com/julialang/user_avatar/discourse.julialang.org/zentrik/32/35409_2.png) [@Zentrik](https://discourse.julialang.org/u/Zentrik)\
**Post date:** [October 16, 2023, 9:53pm UTC](https://discourse.julialang.org/t/issue-with-differential-equation-solver/105008/6 "2023-10-16T21:53:50Z")

</div>

If you run `]st` in the terminal it should print out the versions of the packages.

---

<div class="post-metadata">

**Author:** ![Zentrik](https://sea2.discourse-cdn.com/julialang/user_avatar/discourse.julialang.org/zentrik/32/35409_2.png) [@Zentrik](https://discourse.julialang.org/u/Zentrik)\
**Post date:** [October 16, 2023, 10:00pm UTC](https://discourse.julialang.org/t/issue-with-differential-equation-solver/105008/7 "2023-10-16T22:00:06Z")

</div>

You seem to be running fairly old versions of packages, perhaps run `status --outdated` and try to work that out.

---

<div class="post-metadata">

**Author:** ![ChrisRackauckas](https://sea2.discourse-cdn.com/julialang/user_avatar/discourse.julialang.org/chrisrackauckas/32/77_2.png) [@ChrisRackauckas](https://discourse.julialang.org/u/ChrisRackauckas)\
**Post date:** [October 17, 2023, 7:20am UTC](https://discourse.julialang.org/t/issue-with-differential-equation-solver/105008/8 "2023-10-17T07:20:06Z")

</div>

> [@A\_09](#):
>
> [607db5a9] DifferentialEvolutionMCMC v0.7.6

This package isn’t managing its dependencies well and is keeping everything else outdated. It’s keeping everything back to before PDEs even existed in SciML. I would recommend deleting it.

---

<div class="post-metadata">

**Author:** ![A\_09](https://avatars.discourse-cdn.com/v4/letter/a/f1d935/32.png) [@A\_09](https://discourse.julialang.org/u/A_09)\
**Post date:** [October 17, 2023, 2:53pm UTC](https://discourse.julialang.org/t/issue-with-differential-equation-solver/105008/9 "2023-10-17T14:53:51Z")

</div>

If I updated and deleted the DifferentialEvolutionMCMC v0.7.6 package and the code still does not work, any other suggestions?

---

<div class="post-metadata">

**Author:** ![ChrisRackauckas](https://sea2.discourse-cdn.com/julialang/user_avatar/discourse.julialang.org/chrisrackauckas/32/77_2.png) [@ChrisRackauckas](https://discourse.julialang.org/u/ChrisRackauckas)\
**Post date:** [October 17, 2023, 6:10pm UTC](https://discourse.julialang.org/t/issue-with-differential-equation-solver/105008/10 "2023-10-17T18:10:45Z")

</div>

> [@A\_09](#):
>
> [2e2c70e5] DataFitting v0.1.0

Well this doesn’t even exist. Did you try removing that?

---

<div class="post-metadata">

**Author:** ![A\_09](https://avatars.discourse-cdn.com/v4/letter/a/f1d935/32.png) [@A\_09](https://discourse.julialang.org/u/A_09)\
**Post date:** [October 18, 2023, 10:10am UTC](https://discourse.julialang.org/t/issue-with-differential-equation-solver/105008/11 "2023-10-18T10:10:53Z")

</div>

Yes, I have removed it. It seems that the differential solver is not working, I updated the package and I am facing the same error.

---

<div class="post-metadata">

**Author:** ![ChrisRackauckas](https://sea2.discourse-cdn.com/julialang/user_avatar/discourse.julialang.org/chrisrackauckas/32/77_2.png) [@ChrisRackauckas](https://discourse.julialang.org/u/ChrisRackauckas)\
**Post date:** [October 18, 2023, 10:16am UTC](https://discourse.julialang.org/t/issue-with-differential-equation-solver/105008/12 "2023-10-18T10:16:40Z")

</div>

What does `]st` show now that you have updated everything?

---

<div class="post-metadata">

**Author:** ![A\_09](https://avatars.discourse-cdn.com/v4/letter/a/f1d935/32.png) [@A\_09](https://discourse.julialang.org/u/A_09)\
**Post date:** [October 18, 2023, 10:49am UTC](https://discourse.julialang.org/t/issue-with-differential-equation-solver/105008/13 "2023-10-18T10:49:49Z")

</div>

**Status** `~/.julia/environments/v1.8/Project.toml`

⌃ [093aae92] BSplineKit v0.4.0

⌃ [336ed68f] CSV v0.10.9

⌃ [35d6a980] ColorSchemes v3.20.0

⌃ [a93c6f00] DataFrames v1.3.6

⌃ [0c46a032] DifferentialEquations v6.18.0

⌅ [5b8099bc] DomainSets v0.5.15

⌃ [f6369f11] ForwardDiff v0.10.35

⌃ [34004b35] HypergeometricFunctions v0.3.15

⌃ [4345ca2d] Loess v0.5.4

⌃ [2fda8390] LsqFit v0.11.0

⌃ [961ee093] ModelingToolkit v8.1.0

[76087f3c] NLopt v1.0.0

⌅ [8913a72c] NonlinearSolve v0.3.22

[429524aa] Optim v1.7.8

⌃ [7f7a1694] Optimization v3.11.2

⌃ [36348300] OptimizationOptimJL v0.1.5

⌅ [1dea7af3] OrdinaryDiffEq v5.55.1

[58dd65bb] Plotly v0.4.1

[91a5bcdd] Plots v1.39.0

⌃ [c3e4b0f8] Pluto v0.19.9

⌃ [7f904dfe] PlutoUI v0.7.50

⌃ [f3b207a7] StatsPlots v0.15.1

⌃ [24249f21] SymPy v1.1.12

⌃ [fdbf4ff8] XLSX v0.9.0

[b77e0a4c] InteractiveUtils

[10745b16] Statistics

---

<div class="post-metadata">

**Author:** ![nilshg](https://sea2.discourse-cdn.com/julialang/user_avatar/discourse.julialang.org/nilshg/32/2283_2.png) [@nilshg](https://discourse.julialang.org/u/nilshg)\
**Post date:** [October 18, 2023, 11:03am UTC](https://discourse.julialang.org/t/issue-with-differential-equation-solver/105008/14 "2023-10-18T11:03:36Z")

</div>

Did you call `]up` after removing the other package? The `^`s indicate that you have a lot of package that are not on the latest version. `OrdinaryDiffEq` is currently on 6.58, so 5.55 is quite outdated.

---

<div class="post-metadata">

**Author:** ![A\_09](https://avatars.discourse-cdn.com/v4/letter/a/f1d935/32.png) [@A\_09](https://discourse.julialang.org/u/A_09)\
**Post date:** [October 18, 2023, 11:27am UTC](https://discourse.julialang.org/t/issue-with-differential-equation-solver/105008/15 "2023-10-18T11:27:47Z")

</div>

after the update:

Status `~/.julia/environments/v1.8/Project.toml`  
[093aae92] BSplineKit v0.16.5  
[336ed68f] CSV v0.10.11  
[35d6a980] ColorSchemes v3.24.0  
[a93c6f00] DataFrames v1.6.1  
⌃ [0c46a032] DifferentialEquations v7.10.0  
⌅ [5b8099bc] DomainSets v0.6.7  
[f6369f11] ForwardDiff v0.10.36  
[34004b35] HypergeometricFunctions v0.3.23  
[4345ca2d] Loess v0.6.3  
[2fda8390] LsqFit v0.15.0  
⌃ [961ee093] ModelingToolkit v8.70.0  
[76087f3c] NLopt v1.0.0  
⌅ [8913a72c] NonlinearSolve v1.10.1  
[429524aa] Optim v1.7.8  
[7f7a1694] Optimization v3.19.1  
[36348300] OptimizationOptimJL v0.1.12  
[1dea7af3] OrdinaryDiffEq v6.58.0  
[58dd65bb] Plotly v0.4.1  
[91a5bcdd] Plots v1.39.0  
⌃ [c3e4b0f8] Pluto v0.19.9  
[7f904dfe] PlutoUI v0.7.52  
[f3b207a7] StatsPlots v0.15.6  
[24249f21] SymPy v1.1.14  
[fdbf4ff8] XLSX v0.10.0  
[b77e0a4c] InteractiveUtils  
[10745b16] Statistics  
Info Packages marked with ⌃ and ⌅ have new versions available, but those with ⌅ are restricted by compatibility constraints from upgrading. To see why use `status --outdated`

---

<div class="post-metadata">

**Author:** ![A\_09](https://avatars.discourse-cdn.com/v4/letter/a/f1d935/32.png) [@A\_09](https://discourse.julialang.org/u/A_09)\
**Post date:** [October 19, 2023, 8:09am UTC](https://discourse.julialang.org/t/issue-with-differential-equation-solver/105008/16 "2023-10-19T08:09:29Z")

</div>

The solver is still not working. Do you think it has anything to do with how I wrote the PDE? since I have used the same package for a different equation and it worked (check my initial post).

---

<div class="post-metadata">

**Author:** ![ChrisRackauckas](https://sea2.discourse-cdn.com/julialang/user_avatar/discourse.julialang.org/chrisrackauckas/32/77_2.png) [@ChrisRackauckas](https://discourse.julialang.org/u/ChrisRackauckas)\
**Post date:** [October 19, 2023, 9:17am UTC](https://discourse.julialang.org/t/issue-with-differential-equation-solver/105008/17 "2023-10-19T09:17:47Z")

</div>

Do `]add ModelingToolkit@8.72` what does it say?

You’re still having things hold you back.

---

<div class="post-metadata">

**Author:** ![A\_09](https://avatars.discourse-cdn.com/v4/letter/a/f1d935/32.png) [@A\_09](https://discourse.julialang.org/u/A_09)\
**Post date:** [October 19, 2023, 9:46am UTC](https://discourse.julialang.org/t/issue-with-differential-equation-solver/105008/18 "2023-10-19T09:46:42Z")

</div>

this is what I get:

Updating registry at `~/.julia/registries/General.toml`  
Resolving package versions…  
ERROR: Unsatisfiable requirements detected for package DifferentialEquations [0c46a032]:  
DifferentialEquations [0c46a032] log:  
├─possible versions are: 5.0.0-7.11.0 or uninstalled  
├─restricted to versions \* by an explicit requirement, leaving only versions 5.0.0-7.11.0  
├─restricted by compatibility requirements with OrdinaryDiffEq [1dea7af3] to versions: 6.21.0-7.11.0 or uninstalled, leaving only versions: 6.21.0-7.11.0  
│ └─OrdinaryDiffEq [1dea7af3] log:  
│ ├─possible versions are: 4.0.0-6.58.0 or uninstalled  
│ ├─restricted to versions \* by an explicit requirement, leaving only versions 4.0.0-6.58.0  
│ ├─restricted by compatibility requirements with ModelingToolkit [961ee093] to versions: 6.0.0-6.58.0  
│ │ └─ModelingToolkit [961ee093] log:  
│ │ ├─possible versions are: 0.0.1-8.72.2 or uninstalled  
│ │ └─restricted to versions 8.72 by an explicit requirement, leaving only versions 8.72.0-8.72.2  
│ ├─restricted by compatibility requirements with ArrayInterface [4fba245c] to versions: [4.0.0-5.13.0, 6.11.0-6.58.0] or uninstalled, leaving only versions: 6.11.0-6.58.0  
│ │ └─ArrayInterface [4fba245c] log:  
│ │ ├─possible versions are: 0.0.1-7.4.11 or uninstalled  
│ │ ├─restricted by compatibility requirements with ModelingToolkit [961ee093] to versions: 6.0.0-7.4.11  
│ │ │ └─ModelingToolkit [961ee093] log: see above  
│ │ ├─restricted by compatibility requirements with VectorizationBase [3d5dd08c] to versions: 6.0.1-7.4.11  
│ │ │ └─VectorizationBase [3d5dd08c] log:  
│ │ │ ├─possible versions are: 0.1.0-0.21.64 or uninstalled  
│ │ │ ├─restricted by julia compatibility requirements to versions: 0.20.8-0.21.64 or uninstalled  
│ │ │ ├─restricted by compatibility requirements with LoopVectorization [bdcacae8] to versions: [0.19.8-0.19.39, 0.20.1-0.21.64], leaving only versions: 0.20.8-0.21.64  
│ │ │ │ └─LoopVectorization [bdcacae8] log:  
│ │ │ │ ├─possible versions are: 0.1.0-0.12.165 or uninstalled  
│ │ │ │ ├─restricted by julia compatibility requirements to versions: 0.9.0-0.12.165 or uninstalled  
│ │ │ │ ├─restricted by compatibility requirements with OrdinaryDiffEq [1dea7af3] to versions: 0.12.0-0.12.165  
│ │ │ │ │ └─OrdinaryDiffEq [1dea7af3] log: see above  
│ │ │ │ ├─restricted by compatibility requirements with ArrayInterface [4fba245c] to versions: [0.1.0-0.8.26, 0.12.111-0.12.165] or uninstalled, leaving only versions: 0.12.111-0.12.165  
│ │ │ │ │ └─ArrayInterface [4fba245c] log: see above  
│ │ │ │ └─restricted by compatibility requirements with DocStringExtensions [ffbed154] to versions: [0.1.0-0.6.30, 0.12.114-0.12.165] or uninstalled, leaving only versions: 0.12.114-0.12.165  
│ │ │ │ └─DocStringExtensions [ffbed154] log:  
│ │ │ │ ├─possible versions are: 0.4.6-0.9.3 or uninstalled  
│ │ │ │ ├─restricted by compatibility requirements with ModelingToolkit [961ee093] to versions: 0.7.0-0.9.3  
│ │ │ │ │ └─ModelingToolkit [961ee093] log: see above  
│ │ │ │ ├─restricted by compatibility requirements with Optimization [7f7a1694] to versions: 0.8.0-0.9.3  
│ │ │ │ │ └─Optimization [7f7a1694] log:  
│ │ │ │ │ ├─possible versions are: 3.5.0-3.19.1 or uninstalled  
│ │ │ │ │ ├─restricted to versions \* by an explicit requirement, leaving only versions 3.5.0-3.19.1  
│ │ │ │ │ ├─restricted by compatibility requirements with ModelingToolkit [961ee093] to versions: [3.5.0-3.9.2, 3.9.4-3.19.1] or uninstalled, leaving only versions: [3.5.0-3.9.2, 3.9.4-3.19.1]  
│ │ │ │ │ │ └─ModelingToolkit [961ee093] log: see above  
│ │ │ │ │ └─restricted by compatibility requirements with SciMLBase [0bca4576] to versions: 3.19.0-3.19.1 or uninstalled, leaving only versions: 3.19.0-3.19.1  
│ │ │ │ │ └─SciMLBase [0bca4576] log:  
│ │ │ │ │ ├─possible versions are: 1.0.0-2.4.1 or uninstalled  
│ │ │ │ │ └─restricted by compatibility requirements with ModelingToolkit [961ee093] to versions: 2.0.1-2.4.1  
│ │ │ │ │ └─ModelingToolkit [961ee093] log: see above  
│ │ │ │ ├─restricted by compatibility requirements with JumpProcesses [ccbc3e58] to versions: 0.8.6-0.9.3  
│ │ │ │ │ └─JumpProcesses [ccbc3e58] log:  
│ │ │ │ │ ├─possible versions are: 9.0.0-9.8.0 or uninstalled  
│ │ │ │ │ ├─restricted by compatibility requirements with ModelingToolkit [961ee093] to versions: 9.1.0-9.8.0  
│ │ │ │ │ │ └─ModelingToolkit [961ee093] log: see above  
│ │ │ │ │ └─restricted by compatibility requirements with SciMLBase [0bca4576] to versions: 9.8.0 or uninstalled, leaving only versions: 9.8.0  
│ │ │ │ │ └─SciMLBase [0bca4576] log: see above  
│ │ │ │ └─restricted by compatibility requirements with SymbolicIndexingInterface [2efcf032] to versions: 0.9.0-0.9.3  
│ │ │ │ └─SymbolicIndexingInterface [2efcf032] log:  
│ │ │ │ ├─possible versions are: 0.1.0-0.2.2 or uninstalled  
│ │ │ │ └─restricted by compatibility requirements with SciMLBase [0bca4576] to versions: 0.2.0-0.2.2  
│ │ │ │ └─SciMLBase [0bca4576] log: see above  
│ │ │ └─restricted by compatibility requirements with ArrayInterface [4fba245c] to versions: [0.1.0-0.12.33, 0.21.34-0.21.64] or uninstalled, leaving only versions: 0.21.34-0.21.64  
│ │ │ └─ArrayInterface [4fba245c] log: see above  
│ │ ├─restricted by compatibility requirements with DiffEqBase [2b5f629d] to versions: 7.0.0-7.4.11  
│ │ │ └─DiffEqBase [2b5f629d] log:  
│ │ │ ├─possible versions are: 3.13.2-6.133.1 or uninstalled  
│ │ │ ├─restricted by compatibility requirements with ModelingToolkit [961ee093] to versions: 6.103.0-6.133.1  
│ │ │ │ └─ModelingToolkit [961ee093] log: see above  
│ │ │ └─restricted by compatibility requirements with SciMLBase [0bca4576] to versions: [3.13.2-6.53.6, 6.130.1-6.133.1] or uninstalled, leaving only versions: 6.130.1-6.133.1  
│ │ │ └─SciMLBase [0bca4576] log: see above  
│ │ └─restricted by compatibility requirements with LinearSolve [7ed4a6bd] to versions: 7.4.11  
│ │ └─LinearSolve [7ed4a6bd] log:  
│ │ ├─possible versions are: 0.1.0-2.11.0 or uninstalled  
│ │ ├─restricted by compatibility requirements with OrdinaryDiffEq [1dea7af3] to versions: [1.0.0-1.42.0, 2.1.10-2.11.0]  
│ │ │ └─OrdinaryDiffEq [1dea7af3] log: see above  
│ │ ├─restricted by compatibility requirements with ArrayInterface [4fba245c] to versions: 1.17.0-2.11.0 or uninstalled, leaving only versions: [1.17.0-1.42.0, 2.1.10-2.11.0]  
│ │ │ └─ArrayInterface [4fba245c] log: see above  
│ │ ├─restricted by compatibility requirements with DifferentialEquations [0c46a032] to versions: [1.0.0-1.42.0, 2.1.12-2.11.0], leaving only versions: [1.17.0-1.42.0, 2.1.12-2.11.0]  
│ │ │ └─DifferentialEquations [0c46a032] log: see above  
│ │ ├─restricted by compatibility requirements with DocStringExtensions [ffbed154] to versions: [0.1.0-0.1.6, 1.20.0-2.11.0] or uninstalled, leaving only versions: [1.20.0-1.42.0, 2.1.12-2.11.0]  
│ │ │ └─DocStringExtensions [ffbed154] log: see above  
│ │ └─restricted by compatibility requirements with SciMLBase [0bca4576] to versions: 2.7.0-2.11.0 or uninstalled, leaving only versions: 2.7.0-2.11.0  
│ │ └─SciMLBase [0bca4576] log: see above  
│ ├─restricted by compatibility requirements with DocStringExtensions [ffbed154] to versions: [4.0.0-5.52.2, 6.13.1-6.58.0] or uninstalled, leaving only versions: 6.13.1-6.58.0  
│ │ └─DocStringExtensions [ffbed154] log: see above  
│ └─restricted by compatibility requirements with SciMLBase [0bca4576] to versions: [4.0.0-6.6.6, 6.56.0-6.58.0] or uninstalled, leaving only versions: 6.56.0-6.58.0  
│ └─SciMLBase [0bca4576] log: see above  
├─restricted by compatibility requirements with BoundaryValueDiffEq [764a87c0] to versions: 5.0.0-7.10.0 or uninstalled, leaving only versions: 6.21.0-7.10.0  
│ └─BoundaryValueDiffEq [764a87c0] log:  
│ ├─possible versions are: 2.0.0-5.1.0 or uninstalled  
│ ├─restricted by julia compatibility requirements to versions: 2.0.0-4.0.1 or uninstalled, leaving only versions: 2.0.0-4.0.1  
│ ├─restricted by compatibility requirements with Reexport [189a3867] to versions: 2.6.0-5.1.0 or uninstalled, leaving only versions: 2.6.0-4.0.1  
│ │ └─Reexport [189a3867] log:  
│ │ ├─possible versions are: 0.2.0-1.2.2 or uninstalled  
│ │ └─restricted by compatibility requirements with OptimizationOptimJL [36348300] to versions: 1.2.0-1.2.2  
│ │ └─OptimizationOptimJL [36348300] log:  
│ │ ├─possible versions are: 0.1.1-0.1.12 or uninstalled  
│ │ └─restricted to versions \* by an explicit requirement, leaving only versions 0.1.1-0.1.12  
│ └─restricted by compatibility requirements with SciMLBase [0bca4576] to versions: [2.0.0-2.8.0, 5.0.0-5.1.0] or uninstalled, leaving only versions: 2.6.0-2.8.0  
│ └─SciMLBase [0bca4576] log: see above  
├─restricted by compatibility requirements with SciMLBase [0bca4576] to versions: [5.0.0-7.2.0, 7.10.0-7.11.0] or uninstalled, leaving only versions: [6.21.0-7.2.0, 7.10.0]  
│ └─SciMLBase [0bca4576] log: see above  
├─restricted by compatibility requirements with LinearSolve [7ed4a6bd] to versions: [5.0.0-6.20.0, 7.8.0-7.11.0] or uninstalled, leaving only versions: 7.10.0  
│ └─LinearSolve [7ed4a6bd] log: see above  
└─restricted by compatibility requirements with BoundaryValueDiffEq [764a87c0] to versions: 5.0.0-7.4.0 or uninstalled — no versions left  
└─BoundaryValueDiffEq [764a87c0] log: see above

---

<div class="post-metadata">

**Author:** ![ChrisRackauckas](https://sea2.discourse-cdn.com/julialang/user_avatar/discourse.julialang.org/chrisrackauckas/32/77_2.png) [@ChrisRackauckas](https://discourse.julialang.org/u/ChrisRackauckas)\
**Post date:** [October 19, 2023, 9:53am UTC](https://discourse.julialang.org/t/issue-with-differential-equation-solver/105008/19 "2023-10-19T09:53:38Z")

</div>

Can you start by removing your other junk and simplifying?

---

<div class="post-metadata">

**Author:** ![A\_09](https://avatars.discourse-cdn.com/v4/letter/a/f1d935/32.png) [@A\_09](https://discourse.julialang.org/u/A_09)\
**Post date:** [October 19, 2023, 10:23am UTC](https://discourse.julialang.org/t/issue-with-differential-equation-solver/105008/20 "2023-10-19T10:23:48Z")

</div>

you mean packages that are not in use?

[Next page](https://discourse.julialang.org/t/issue-with-differential-equation-solver/105008.md?page=2)