Dear Friends I am trying to solve an ode problem function myfun(du,u,p,t) where u consists of the vectors x,z,e. I want this function return solution just for e (I do not know how must I do this) Here is the code which I have used for it using DifferentialEquations using LinearAlgebra using P…

[image] aiiiob_bie: dx[1] That variable doesn’t exist. Why not just write du[1] = x[2]?

Thank so much for your reply. I wanted to assume u as an array of x ,z,e In fact my problem is solving 6 odes but in the function command I faced to a limitation which is in “my fun” function I could just one function namely as u so I decided to for u as a vector that its first derivative is …

[image] aiiiob_bie: x, z, e = u Those are all scalars, so z[2] doesn’t make sense. Did you mean: x = @view u[1:2] u = @view u[3:4] e = @view u[5,6] You might want to look at this package as a nice abstraction: [image] GitHub - jonniedie/ComponentArrays.jl: Arrays with arbitrarily …

Yes, what I mentioned above should work. Did you try it? Or did you try ComponentArrays.jl as an abstraction?

unfortunately I could not install ComponentArrays julia> import Pkg julia> Pkg.add(“ComponentArray”) Updating registry at C:\Users\user\.julia\registries\General Updating registry at C:\Users\user\.julia\registries\JuliaComputingRegistry ERROR: The following package names could not be resolved: …

[image] aiiiob_bie: Pkg.add(“ComponentArray”) Pkg.add(“ComponentArrays”)

Are there examples applying this type of indexing? Must ComponentArrays.jl be installed for it? (x = @view u[1:2] u = @view u[3:4] e = @view u[5,6])

Thank you so much sorry for my primitive questions.

Dear Chris I read the section for ODE in [image] GitHub - jonniedie/ComponentArrays.jl: Arrays with arbitrarily nested named... Arrays with arbitrarily nested named components. Contribute to jonniedie/ComponentArrays.jl development by creating an account on GitHub. …

ODE with vector Argument

New to Julia

John_Gibson July 20, 2021, 9:28pm 18

@aiiiob_bie This link shows you how to use backticks to format your code snippets nicely and other helpful things: Please read: make it easier to help you

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ODE with vector Argument

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