ODE solver for BVProblem never calls the provided function for boundary conditions

P0p5 · February 3, 2025, 6:07pm

Please tell me where to find this information in the online Julia documentation.
thanks.

ErikQQY · February 3, 2025, 6:10pm

P0p5:

ErikQQY:

FIRK methods don’t have automatic step size choosing, so you must provide a dt in your solve

To solve a BVP, you should use RadauIIa5 instead of RadauIIA5

When I do that, while also saying “using BoundaryValueDiffEqFIRK, ArgCheck”,
I get:

```ERROR: LoadError: UndefVarError: RadauIIa5 not defined in Main
Suggestion: check for spelling errors or missing imports.
Stacktrace:
[1] top-level scope
@ ~/Applications/Julia/RealisticSeismology-main/BVProblem,Example2.jl:47
[2] include(fname::String)
@ Main ./sysimg.jl:38
[3] top-level scope
@ REPL[446]:1
in expression starting at /Users/andy 1/Applications/Julia/RealisticSeismology-main/BVProblem,Example2.jl:47
So which package contains "RadauIIa5"?

Please try using BoundaryValueDiffEqFIRK in your REPL and check if there are errors.

P0p5 · February 3, 2025, 6:11pm

And please tell me where to find this “obvious” information in the online Julia documentation.
Thanks

ErikQQY · February 3, 2025, 6:12pm

See: BVP Solvers · DifferentialEquations.jl

P0p5 · February 3, 2025, 6:13pm

Same result.

ErikQQY · February 3, 2025, 6:19pm

That is unlikely to happen, could you try in your REPL:

julia> using BoundaryValueDiffEqFIRK

julia> RadauIIa5
RadauIIa5

And if the UndefVarError still occurs, could you post your julia version and Pkg.status(; mode = PKGMODE_MANIFEST)?

P0p5 · February 3, 2025, 6:23pm

Here is the result:


julia> RadauIIa5
ERROR: UndefVarError: `RadauIIa5` not defined in `Main`
Suggestion: check for spelling errors or missing imports.

ErikQQY · February 3, 2025, 6:24pm

What about

julia> using BoundaryValueDiffEqFIRK

julia> RadauIIa5
RadauIIa5

P0p5 · February 3, 2025, 6:25pm

What appeared is less than I pasted. Trying again…


julia> using BoundaryValueDiffEqFIRK

julia> RadauIIa5
ERROR: UndefVarError: `RadauIIa5` not defined in `Main`
Suggestion: check for spelling errors or missing imports.

julia>

P0p5 · February 3, 2025, 6:26pm

I suspect that you have also installed some other package containing RadauIIa5.

Try ]st

P0p5 · February 3, 2025, 6:30pm

And as I have yet to find any example of an initialguess function in the online documentation,
could you please provide such an example?
thanks

ErikQQY · February 3, 2025, 6:30pm

That’s really weird since I am using an empty environment with only BoundaryValueDiffEqFIRK.jl installed.

Could you share your Pkg.status(; mode = PKGMODE_MANIFEST)?

ErikQQY · February 3, 2025, 6:32pm

That’s indeed some issues with BoundaryValueDiffEq.jl for not having enough documentations on how to provide initial guesses, will fix this issue ASAP

P0p5 · February 3, 2025, 6:33pm


(@v1.11) pkg> status
Status `~/.julia/environments/v1.11/Project.toml`
  [dce04be8] ArgCheck v2.4.0
  [85d9eb09] BoundaryValueDiffEqFIRK v1.4.0
  [90137ffa] StaticArrays v1.9.11

(@v1.11) pkg> status(; mode = PKGMODE_MANIFEST)
ERROR: `status(` is not a recognized command. Type ? for help with available commands

P0p5 · February 3, 2025, 6:35pm

Ok, but could you perhaps provide such a (maximal) example right here in this discourse?

thanks

ErikQQY · February 3, 2025, 6:41pm

Sure, see

github.com/SciML/BoundaryValueDiffEq.jl

lib/BoundaryValueDiffEqFIRK/test/expanded/firk_basic_tests.jl

508629f83


      
          @testitem "Solve using Continuation" begin
              using RecursiveArrayTools
          
              g = 9.81
              L = 1.0
              tspan = (0.0, pi / 2)
              function simplependulum!(du, u, p, t)
                  θ = u[1]
                  dθ = u[2]
                  du[1] = dθ
                  du[2] = -(g / L) * sin(θ)
              end
          
              function bc2a!(resid_a, u_a, p) # u_a is at the beginning of the time span
                  x0 = p
                  resid_a[1] = u_a[1] - x0 # the solution at the beginning of the time span should be -pi/2
              end
              function bc2b!(resid_b, u_b, p) # u_b is at the ending of the time span
                  x0 = p
                  resid_b[1] = u_b[1] - pi / 2 # the solution at the end of the time span should be pi/2

This file has been truncated. show original

ErikQQY · February 3, 2025, 6:44pm

P0p5:


(@v1.11) pkg> status
Status `~/.julia/environments/v1.11/Project.toml`
  [dce04be8] ArgCheck v2.4.0
  [85d9eb09] BoundaryValueDiffEqFIRK v1.4.0
  [90137ffa] StaticArrays v1.9.11

(@v1.11) pkg> status(; mode = PKGMODE_MANIFEST)
ERROR: `status(` is not a recognized command. Type ? for help with available commands

I have never encounter such error, and I can’t even reproduce this error. So you successfully using BoundaryValueDiffEqFIRK(‘successfully’ means no other errors), but when you try calling RadauIIa5 and there is still UndefVarError?

P0p5 · February 3, 2025, 6:49pm

Thank you!

And may I suggest that the

No other errors. And that package seems to be there…

julia> RadauIIA5
RadauIIA5

julia>

P0p5 · February 3, 2025, 6:51pm

I guess this “RadauIIa5” may be hiding somewhere else in your system?

P0p5 · February 3, 2025, 6:53pm

Whose idea was it to have two different modules with names differing only by the case of only one character in the middle of the names?

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ODE solver for BVProblem never calls the provided function for boundary conditions

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