# Unexpected behavior when returning DifferentialEquations solve() solution from external .jl file

**URL:** <https://discourse.julialang.org/t/unexpected-behavior-when-returning-differentialequations-solve-solution-from-external-jl-file/112263>\
**Category:** General Usage\
**Tags:** question\
**Created:** [March 29, 2024, 1:07am UTC](https://discourse.julialang.org/t/unexpected-behavior-when-returning-differentialequations-solve-solution-from-external-jl-file/112263 "2024-03-29T01:07:08Z")\
**Posts on this page:** 2\
**Page:** 1

<div class="post-metadata">

**Author:** ![thedeyan](https://avatars.discourse-cdn.com/v4/letter/t/6bbea6/32.png) [@thedeyan](https://discourse.julialang.org/u/thedeyan)\
**Post date:** [March 29, 2024, 1:07am UTC](https://discourse.julialang.org/t/unexpected-behavior-when-returning-differentialequations-solve-solution-from-external-jl-file/112263/1 "2024-03-29T01:07:08Z")

</div>

I am new to Julia. I am trying to use the `DifferentialEquations.jl` to solve, well, some ODEs, via Python. I can, for example, use the following `python` script to solve the Lorenz attractor:

```julia
from diffeqpy import de
from julia import Main

jul_f = Main.eval("""
function f(dy,y,p,t)
    x, y, z = y
    sigma, rho, beta = p
    dy[1] = sigma * (y - x)
    dy[2] = x * (rho - z) - y
    dy[3] = x * y - beta * z
end""")
u0 = [1.0,0.0,0.0]
tspan = (0., 100.)
p = [10.0,28.0,2.66]
prob = de.ODEProblem(jul_f, u0, tspan, p)
sol = de.solve(prob)

```

after which `sol` is an object with attributes I can interrogate, e.g. `sol.t` contains the `t` values and `sol.u` contains the solution.

In comparison, if I put everything in a separate file, `MySol.jl` like this:

```julia
using DifferentialEquations
using BenchmarkTools

function f(dy,y,p,t)
    x, y, z = y
    sigma, rho, beta = p
    dy[1] = sigma * (y - x)
    dy[2] = x * (rho - z) - y
    dy[3] = x * y - beta * z
end

function solver(u0, t_start, t_end, p)
    problem = ODEProblem(f, u0, (t_start, t_end), p)
    sol = solve(problem)
    return sol
end

```

and then in `python` do the following:

```julia
from julia import Main

Main.include("MySol.jl")

u0 = [1.0,0.0,0.0]
tspan = (0., 100.)
p = [10.0,28.0,2.66]

sol = Main.solver(u0, t_span[0], t_span[1], p)

```

then `sol` is simply an array which contains the (correct) y-values for the solution and nothing of the remaining values which would be in the struct. Is there a way to fix this so that I can recover the whole solution object and not just the y-values?

---

<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:** [April 1, 2024, 2:01am UTC](https://discourse.julialang.org/t/unexpected-behavior-when-returning-differentialequations-solve-solution-from-external-jl-file/112263/2 "2024-04-01T02:01:14Z")

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@c42f maybe you might know why PythonCall would convert here? I don’t know why it would do a conversion if you use include like that.