OrdinaryDiffEq.jl
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Published
20 hours ago •
SciML
SciML
FBDF not taking any timesteps except at the start and end on RLC circuit
Describe the bug 🐞
I have created a circuit in MSL representing a transmision line with an end point dampening and solved it with FBDF. The output is just a single line segement, with just times recorded for start and end. This is wrong as I know the circuit solves (e.g with Rodas5P or IDA) to give a sinusioid.
Expected behavior
Solution should be a siniusoid and should match other solves
Minimal Reproducible Example 👇
Sorry it is not yet minimized
using ModelingToolkitStandardLibrary.Electrical, ModelingToolkit, OrdinaryDiffEq
using ModelingToolkitStandardLibrary.Blocks: Constant, Sine
connections = Equation[]
add_conn!(x) = (push!(connections, x); x) # to match spice we want to interleave connections and declarations
systems = ODESystem[]
add_system!(x) = (push!(systems, x); x)
@named ground = Ground()
add_system!(ground)
@named Src = Sine(amplitude=1, frequency=100e6)
add_system!(Src)
@named Vsin = Voltage()
add_system!(Vsin)
connect(Src.output, Vsin.V) |> add_conn!
connect(Vsin.n, ground.g) |> add_conn!
@named Rsrc = Resistor(R=250)
add_system!(Rsrc)
connect(Rsrc.n, Vsin.p) |> add_conn!
c_match = 1.5e-12
l_match = 400e-9
@named Lmatch = Inductor(L=l_match)
add_system!(Lmatch)
connect(Rsrc.p, Lmatch.n) |> add_conn!
@named Cmatch = Capacitor(C=c_match)
add_system!(Cmatch)
connect(Rsrc.p, Cmatch.p) |> add_conn!
connect(ground.g, Cmatch.n) |> add_conn!
function TransmissionLineSegment!(_vin, _ii)
l=0.05e-9
c=0.02e-12
L1 = Inductor(L=l, name=Symbol(:L1_, _ii)) |> add_system!
_vout = L1.p
connect(_vin, L1.n) |> add_conn!
C1 = Capacitor(C=c, name=Symbol(:C1_, _ii)) |> add_system!
connect(C1.n, ground.g) |> add_conn!
connect(C1.p, _vout) |> add_conn!
return _vout
end
ii=0
prev = TransmissionLineSegment!(Lmatch.p, (ii+=1))
prev = TransmissionLineSegment!(prev, (ii+=1))
prev = TransmissionLineSegment!(prev, (ii+=1))
prev = TransmissionLineSegment!(prev, (ii+=1))
prev = TransmissionLineSegment!(prev, (ii+=1))
prev = TransmissionLineSegment!(prev, (ii+=1))
prev = TransmissionLineSegment!(prev, (ii+=1))
prev = TransmissionLineSegment!(prev, (ii+=1))
prev = TransmissionLineSegment!(prev, (ii+=1))
vout = TransmissionLineSegment!(prev, (ii+=1))
@named Rload = Resistor(R=50)
add_system!(Rload)
connect(Rload.n, ground.g) |> add_conn!
connect(Rload.p, vout) |> add_conn!
@variables t
@named imp_model = ODESystem(connections, t ;systems)
sys = structural_simplify(imp_model)
prob = ODEProblem(sys, Pair[], (0.0, 4e-8),)
sol = solve(prob, FBDF())
Error & Stacktrace ⚠️
julia> sol = solve(prob, FBDF())
retcode: Success
Interpolation: 3rd order Hermite
t: 2-element Vector{Float64}:
0.0
4.0e-8
u: 2-element Vector{Vector{Float64}}:
[0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0 … 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0]
[-1.8927928067770185e-16, 3.1546546615353092e-18, -1.5772879074402175e-16, 3.1545757971399373e-18, -1.5772484752427531e-16, 3.1544969347161753e-18, -1.5772090440310693e-16, 3.1544180742639735e-18, -1.5771696138051409e-16, 3.1543392157832834e-18 … -1.5770907563104526e-16, 3.15418150473624e-18, -1.5770513290416435e-16, 3.1541026521697875e-18, -1.5770119027584911e-16, 3.1540238015746497e-18, -1.5769724774609715e-16, 3.1539449529507766e-18, -1.5769330531490595e-16, 3.154654661535309e-17]
See only 2 versions
Environment (please complete the following information):
- Output of
using Pkg; Pkg.status()
(repro_fbdf_bug) pkg> st
Status `~/JuliaEnvs/repro_fbdf_bug/Project.toml`
[961ee093] ModelingToolkit v9.1.0
[16a59e39] ModelingToolkitStandardLibrary v2.5.0
[1dea7af3] OrdinaryDiffEq v6.72.0
- Output of
using Pkg; Pkg.status(; mode = PKGMODE_MANIFEST)
(repro_fbdf_bug) pkg> st --manifest
Status `~/JuliaEnvs/repro_fbdf_bug/Manifest.toml`
[47edcb42] ADTypes v0.2.6
[1520ce14] AbstractTrees v0.4.5
[79e6a3ab] Adapt v4.0.1
⌅ [ec485272] ArnoldiMethod v0.2.0
[4fba245c] ArrayInterface v7.7.1
[4c555306] ArrayLayouts v1.6.0
[e2ed5e7c] Bijections v0.1.6
[62783981] BitTwiddlingConvenienceFunctions v0.1.5
[2a0fbf3d] CPUSummary v0.2.4
[00ebfdb7] CSTParser v3.4.1
[49dc2e85] Calculus v0.5.1
[d360d2e6] ChainRulesCore v1.22.1
[fb6a15b2] CloseOpenIntervals v0.1.12
[861a8166] Combinatorics v1.0.2
[a80b9123] CommonMark v0.8.12
[38540f10] CommonSolve v0.2.4
[bbf7d656] CommonSubexpressions v0.3.0
[34da2185] Compat v4.14.0
[b152e2b5] CompositeTypes v0.1.3
[2569d6c7] ConcreteStructs v0.2.3
[187b0558] ConstructionBase v1.5.4
[adafc99b] CpuId v0.3.1
[a8cc5b0e] Crayons v4.1.1
[9a962f9c] DataAPI v1.16.0
[864edb3b] DataStructures v0.18.17
[e2d170a0] DataValueInterfaces v1.0.0
[2b5f629d] DiffEqBase v6.147.1
[459566f4] DiffEqCallbacks v3.2.0
[163ba53b] DiffResults v1.1.0
[b552c78f] DiffRules v1.15.1
[31c24e10] Distributions v0.25.107
[ffbed154] DocStringExtensions v0.9.3
[5b8099bc] DomainSets v0.7.5
[fa6b7ba4] DualNumbers v0.6.8
[7c1d4256] DynamicPolynomials v0.5.5
⌅ [06fc5a27] DynamicQuantities v0.11.3
[4e289a0a] EnumX v1.0.4
[f151be2c] EnzymeCore v0.6.5
[d4d017d3] ExponentialUtilities v1.26.1
[e2ba6199] ExprTools v0.1.10
[7034ab61] FastBroadcast v0.2.8
[9aa1b823] FastClosures v0.3.2
[29a986be] FastLapackInterface v2.0.2
[1a297f60] FillArrays v1.9.3
[64ca27bc] FindFirstFunctions v1.2.0
[6a86dc24] FiniteDiff v2.22.0
[59287772] Formatting v0.4.3
[f6369f11] ForwardDiff v0.10.36
[069b7b12] FunctionWrappers v1.1.3
[77dc65aa] FunctionWrappersWrappers v0.1.3
[d9f16b24] Functors v0.4.7
[46192b85] GPUArraysCore v0.1.6
[c145ed77] GenericSchur v0.5.3
[c27321d9] Glob v1.3.1
[86223c79] Graphs v1.9.0
[3e5b6fbb] HostCPUFeatures v0.1.16
[34004b35] HypergeometricFunctions v0.3.23
[615f187c] IfElse v0.1.1
[d25df0c9] Inflate v0.1.4
[8197267c] IntervalSets v0.7.10
[92d709cd] IrrationalConstants v0.2.2
[82899510] IteratorInterfaceExtensions v1.0.0
[692b3bcd] JLLWrappers v1.5.0
[682c06a0] JSON v0.21.4
[98e50ef6] JuliaFormatter v1.0.50
[ccbc3e58] JumpProcesses v9.10.1
[ef3ab10e] KLU v0.5.0
[ba0b0d4f] Krylov v0.9.5
[b964fa9f] LaTeXStrings v1.3.1
[2ee39098] LabelledArrays v1.15.1
[984bce1d] LambertW v0.4.6
[23fbe1c1] Latexify v0.16.1
[10f19ff3] LayoutPointers v0.1.15
[5078a376] LazyArrays v1.8.3
[d3d80556] LineSearches v7.2.0
[7ed4a6bd] LinearSolve v2.25.0
[2ab3a3ac] LogExpFunctions v0.3.27
[bdcacae8] LoopVectorization v0.12.166
[d8e11817] MLStyle v0.4.17
[1914dd2f] MacroTools v0.5.13
[d125e4d3] ManualMemory v0.1.8
[a3b82374] MatrixFactorizations v2.1.0
[bb5d69b7] MaybeInplace v0.1.1
[e1d29d7a] Missings v1.1.0
[961ee093] ModelingToolkit v9.1.0
[16a59e39] ModelingToolkitStandardLibrary v2.5.0
[46d2c3a1] MuladdMacro v0.2.4
[102ac46a] MultivariatePolynomials v0.5.4
[d8a4904e] MutableArithmetics v1.4.1
[d41bc354] NLSolversBase v7.8.3
[77ba4419] NaNMath v1.0.2
[8913a72c] NonlinearSolve v3.7.3
[6fe1bfb0] OffsetArrays v1.13.0
[bac558e1] OrderedCollections v1.6.3
[1dea7af3] OrdinaryDiffEq v6.72.0
[90014a1f] PDMats v0.11.31
[65ce6f38] PackageExtensionCompat v1.0.2
[d96e819e] Parameters v0.12.3
[69de0a69] Parsers v2.8.1
[e409e4f3] PoissonRandom v0.4.4
[f517fe37] Polyester v0.7.9
[1d0040c9] PolyesterWeave v0.2.1
[d236fae5] PreallocationTools v0.4.20
[aea7be01] PrecompileTools v1.2.0
[21216c6a] Preferences v1.4.1
[1fd47b50] QuadGK v2.9.4
[e6cf234a] RandomNumbers v1.5.3
[3cdcf5f2] RecipesBase v1.3.4
[731186ca] RecursiveArrayTools v3.10.1
[f2c3362d] RecursiveFactorization v0.2.21
[189a3867] Reexport v1.2.2
[ae029012] Requires v1.3.0
[79098fc4] Rmath v0.7.1
[7e49a35a] RuntimeGeneratedFunctions v0.5.12
[94e857df] SIMDTypes v0.1.0
[476501e8] SLEEFPirates v0.6.42
[0bca4576] SciMLBase v2.29.0
[c0aeaf25] SciMLOperators v0.3.8
[53ae85a6] SciMLStructures v1.1.0
[efcf1570] Setfield v1.1.1
[727e6d20] SimpleNonlinearSolve v1.5.0
[699a6c99] SimpleTraits v0.9.4
[ce78b400] SimpleUnPack v1.1.0
[a2af1166] SortingAlgorithms v1.2.1
[47a9eef4] SparseDiffTools v2.17.0
[e56a9233] Sparspak v0.3.9
[276daf66] SpecialFunctions v2.3.1
[aedffcd0] Static v0.8.10
[0d7ed370] StaticArrayInterface v1.5.0
[90137ffa] StaticArrays v1.9.3
[1e83bf80] StaticArraysCore v1.4.2
[10745b16] Statistics v1.11.1
[82ae8749] StatsAPI v1.7.0
[2913bbd2] StatsBase v0.34.2
[4c63d2b9] StatsFuns v1.3.1
[7792a7ef] StrideArraysCore v0.5.2
[2efcf032] SymbolicIndexingInterface v0.3.8
[d1185830] SymbolicUtils v1.5.0
[0c5d862f] Symbolics v5.22.1
[3783bdb8] TableTraits v1.0.1
[bd369af6] Tables v1.11.1
[8290d209] ThreadingUtilities v0.5.2
[a759f4b9] TimerOutputs v0.5.23
[0796e94c] Tokenize v0.5.28
[d5829a12] TriangularSolve v0.1.20
[410a4b4d] Tricks v0.1.8
[781d530d] TruncatedStacktraces v1.4.0
[5c2747f8] URIs v1.5.1
[3a884ed6] UnPack v1.0.2
[1986cc42] Unitful v1.19.0
[a7c27f48] Unityper v0.1.6
[3d5dd08c] VectorizationBase v0.21.65
[19fa3120] VertexSafeGraphs v0.2.0
[1d5cc7b8] IntelOpenMP_jll v2024.0.2+0
[856f044c] MKL_jll v2024.0.0+0
[efe28fd5] OpenSpecFun_jll v0.5.5+0
[f50d1b31] Rmath_jll v0.4.0+0
[0dad84c5] ArgTools v1.1.2
[56f22d72] Artifacts v1.11.0
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[ade2ca70] Dates v1.11.0
[8ba89e20] Distributed v1.11.0
[f43a241f] Downloads v1.6.0
[7b1f6079] FileWatching v1.11.0
[9fa8497b] Future v1.11.0
[b77e0a4c] InteractiveUtils v1.11.0
[4af54fe1] LazyArtifacts v1.11.0
[b27032c2] LibCURL v0.6.4
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[56ddb016] Logging v1.11.0
[d6f4376e] Markdown v1.11.0
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[ea8e919c] SHA v0.7.0
[9e88b42a] Serialization v1.11.0
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[8dfed614] Test v1.11.0
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[4ec0a83e] Unicode v1.11.0
[e66e0078] CompilerSupportLibraries_jll v1.1.0+0
[deac9b47] LibCURL_jll v8.6.0+0
[e37daf67] LibGit2_jll v1.7.1+0
[29816b5a] LibSSH2_jll v1.11.0+1
[c8ffd9c3] MbedTLS_jll v2.28.6+0
[14a3606d] MozillaCACerts_jll v2023.1.10
[4536629a] OpenBLAS_jll v0.3.26+2
[05823500] OpenLibm_jll v0.8.1+2
[bea87d4a] SuiteSparse_jll v7.6.0+0
[83775a58] Zlib_jll v1.2.13+1
[8e850b90] libblastrampoline_jll v5.8.0+1
[8e850ede] nghttp2_jll v1.59.0+0
[3f19e933] p7zip_jll v17.4.0+2
Info Packages marked with ⌅ have new versions available but compatibility constraints restrict them from upgrading. To see why use `status --outdated -m`
- output of versioninfo
julia> versioninfo()
Julia Version 1.11.0-DEV.1547
Commit a59f2192ac (2024-02-10 18:26 UTC)
Platform Info:
OS: Linux (x86_64-linux-gnu)
CPU: 20 × 12th Gen Intel(R) Core(TM) i7-12700H
WORD_SIZE: 64
LLVM: libLLVM-16.0.6 (ORCJIT, alderlake)
Threads: 1 default, 0 interactive, 1 GC (on 20 virtual cores)
I minimized this slightly:
using OrdinaryDiffEq
using ModelingToolkitStandardLibrary.Electrical, ModelingToolkit, OrdinaryDiffEq
using ModelingToolkitStandardLibrary.Blocks: Constant, Sine
connections = Equation[]
add_conn!(x) = (push!(connections, x); x) # to match spice we want to interleave connections and declarations
systems = ODESystem[]
add_system!(x) = (push!(systems, x); x)
@named ground = Ground()
add_system!(ground)
@named Src = Sine(amplitude=1, frequency=100e6)
add_system!(Src)
@named Vsin = Voltage()
add_system!(Vsin)
connect(Src.output, Vsin.V) |> add_conn!
connect(Vsin.n, ground.g) |> add_conn!
@named Rsrc = Resistor(R=250)
add_system!(Rsrc)
connect(Rsrc.n, Vsin.p) |> add_conn!
c_match = 1.5e-12
l_match = 400e-9
@named Lmatch = Inductor(L=l_match)
add_system!(Lmatch)
connect(Rsrc.p, Lmatch.n) |> add_conn!
@named Cmatch = Capacitor(C=c_match)
add_system!(Cmatch)
connect(Rsrc.p, Cmatch.p) |> add_conn!
connect(ground.g, Cmatch.n) |> add_conn!
function TransmissionLineSegment!(_vin, _ii)
l=0.05e-9
c=0.02e-12
L1 = Inductor(L=l, name=Symbol(:L1_, _ii)) |> add_system!
_vout = L1.p
connect(_vin, L1.n) |> add_conn!
C1 = Capacitor(C=c, name=Symbol(:C1_, _ii)) |> add_system!
connect(C1.n, ground.g) |> add_conn!
connect(C1.p, _vout) |> add_conn!
return _vout
end
vout = TransmissionLineSegment!(Lmatch.p, 1)
# vout = Lmatch.p
@named Rload = Resistor(R=50)
add_system!(Rload)
connect(Rload.n, ground.g) |> add_conn!
connect(Rload.p, vout) |> add_conn!
@variables t
@named imp_model = ODESystem(connections, t ;systems)
sys = structural_simplify(imp_model)
prob = ODEProblem(sys, Pair[], (0.0, 4e-8),)
sol = solve(prob, FBDF())
Note the commented-out line I added; if we drop the TransmissionLineSegment and instead just set vout = Lmatch.p, it simulates correctly:
@oscardssmith suggested I check whether setting dt=1e-10 helps, and it does; I get a reasonable solve output with that set.
As mentioned in our chat, it's just from hitting the fundamental frequency. Anything that's not exactly a multiple of 1e-8 will work fine.
using Plots
sol = solve(prob, FBDF(), dt = 1.000001e-8)
plot(sol)
It's a very special case that only comes up if you just happen to hit all zeros in the derivative estimates.
