# Comparing Plot Outputs for Different Versions of Julia

**URL:** <https://discourse.julialang.org/t/comparing-plot-outputs-for-different-versions-of-julia/101538>\
**Category:** Modelling & Simulations\
**Tags:** diffeq, mtk\
**Created:** [July 12, 2023, 2:58pm UTC](https://discourse.julialang.org/t/comparing-plot-outputs-for-different-versions-of-julia/101538 "2023-07-12T14:58:42Z")\
**Posts on this page:** 4\
**Page:** 1

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**Author:** ![emmabottomley](https://avatars.discourse-cdn.com/v4/letter/e/eb8c5e/32.png) [@emmabottomley](https://discourse.julialang.org/u/emmabottomley)\
**Post date:** [July 12, 2023, 2:58pm UTC](https://discourse.julialang.org/t/comparing-plot-outputs-for-different-versions-of-julia/101538/1 "2023-07-12T14:58:42Z")

</div>

Hello!  
I’m working on solving PDEs in julia and producing plots of their solutions for different lengths of time.  
I was having a lot of issues when using Julia v-1.9.0. When I increased the time in this specific setting past t=10, I had no issues with v-1.8.1 but the graphs fall apart when I use v-1.9.0 - see below

 ![Screen Shot 2023-07-12 at 10.55.15 AM](https://global.discourse-cdn.com/julialang/original/3X/1/4/142a8b27b1c61d95adb18d398619374ab2cfbf48.png)

here is a copy of my code

```julia
using OrdinaryDiffEq, ModelingToolkit, MethodOfLines, DomainSets, DifferentialEquations, Plots, LinearAlgebra

# Method of Manufactured Solutions: exact solution

# model parameters

Q = 0.002
p = 0.5
Dc = 0.0002
mu = 6.0
Yu = 0.587
ku = 0.2
X_inf = 10000.0
d = 0.5
a = 0.5
Y_lambda = 0.587
eta = Y_lambda/X_inf
kd = 0.4
D = 0.0002
flux(S,L) = D*mu*((S/(p-2*L))/(ku+(S/(p-2*L))))*L 
g(S,L) = mu*((S/(p-2*L))/(ku+(S/(p-2*L))))

# Parameters, variables, and derivatives

@parameters t x
@variables S(..), W(..), L(..)
Dt = Differential(t)
Dx = Differential(x)
Dxx = Differential(x)^2

# 1D PDE and boundary conditions
eq = [Dt(S(t, x)) ~ (-Q*(p-2*L(t,x))*Dx(S(t,x)) + Q*S(t,x)*(-2)*Dx((L(t,x))))/(p-2*L(t,x))^2 + (Dc*(p-2*L(t,x))*Dxx(S(t,x)) - Dc*(-2)*Dxx(L(t,x))*(S(t,x)))/(p-2*L(t,x))^2 - 2*flux(S(t,x),L(t,x)) - (W(t,x)/Yu)*g(S(t,x),L(t,x)),
     Dt(W(t, x)) ~ (-Q*(p-2*L(t,x))*Dx(W(t,x)) + Q*W(t,x)*(-2)*Dx((L(t,x))))/(p-2*L(t,x))^2 + (Dc*(p-2*L(t,x))*Dxx(W(t,x)) - Dc*(-2)*Dxx(L(t,x))*(W(t,x)))/(p-2*L(t,x))^2 + 2*X_inf*d*L(t,x) - 2*a*W(t,x) + g(S(t,x),L(t,x))*W(t,x),
     Dt(L(t, x)) ~ eta*flux(S(t,x),L(t,x)) - (kd+d)L(t,x) + (a*W(t,x))/(X_inf)]

bcs = [S(0, x) ~ 5,
       S(t, 0) ~ 5,
       Dx(S(t,0)) ~ 0.0,
        W(0, x) ~ 0.0,
       W(t, 0) ~ 0.005,
       Dx(W(t,0)) ~ 0.0,
        L(0, x) ~ 0.00]

# Space and time domains
domains = [t ∈ Interval(0.0, 20.0),
           x ∈ Interval(0.0, 1)]

# PDE system
@named pdesys = PDESystem(eq, bcs, domains, [t, x], [S(t, x), W(t,x), L(t,x)])

# Method of lines discretization
dx = 0.01
order = 2
discretization = MOLFiniteDifference([x => dx], t)

# Convert the PDE problem into an ODE problem
prob = discretize(pdesys,discretization)

# Solve ODE problem
sol = solve(prob, Rosenbrock23(), saveat=2)

# Plot results and compare with exact solution
discrete_x = sol[x]
discrete_t = sol[t]

solL = sol[L(t,x)]
solC = sol[S(t,x)]./(p.-2 .*solL)
solU = sol[W(t,x)]./(p.-2 .*solL)

p1 = plot()
for i in 1:length(discrete_t)
    plot!(discrete_x, solC[i, :], title="Numerical C", label="t=$(discrete_t[i])")
end
p2 = plot()
for i in 1:length(discrete_t)
	plot!(discrete_x, solU[i,:], title="Numerical U", label="t=$(discrete_t[i])")
end
p3 = plot()
for i in 1:length(discrete_t)
    plot!(discrete_x, solL[i, :], title="Numerical L", label="t=$(discrete_t[i])")
end

p = plot(p1, p2, p3, legend=:false)

```

Does anyone know why this is happening? Or how to make them work properly on v-1.9.0?  
Thanks!

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<div class="post-metadata">

**Author:** ![xtalax](https://sea2.discourse-cdn.com/julialang/user_avatar/discourse.julialang.org/xtalax/32/35293_2.png) [@xtalax](https://discourse.julialang.org/u/xtalax)\
**Post date:** [July 13, 2023, 8:24pm UTC](https://discourse.julialang.org/t/comparing-plot-outputs-for-different-versions-of-julia/101538/2 "2023-07-13T20:24:06Z")

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Can you post the output of `] st` for both versions?

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<div class="post-metadata">

**Author:** ![emmabottomley](https://avatars.discourse-cdn.com/v4/letter/e/eb8c5e/32.png) [@emmabottomley](https://discourse.julialang.org/u/emmabottomley)\
**Post date:** [July 13, 2023, 10:06pm UTC](https://discourse.julialang.org/t/comparing-plot-outputs-for-different-versions-of-julia/101538/3 "2023-07-13T22:06:31Z")

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![Screen Shot 2023-07-13 at 6.06.08 PM](https://global.discourse-cdn.com/julialang/original/3X/c/c/cce0feb7c2e27bf1e93519751c789bca848a8b92.jpeg)

---

<div class="post-metadata">

**Author:** ![xtalax](https://sea2.discourse-cdn.com/julialang/user_avatar/discourse.julialang.org/xtalax/32/35293_2.png) [@xtalax](https://discourse.julialang.org/u/xtalax)\
**Post date:** [July 15, 2023, 12:18am UTC](https://discourse.julialang.org/t/comparing-plot-outputs-for-different-versions-of-julia/101538/4 "2023-07-15T00:18:05Z")

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First thing I’d try is to run `] update` on both and see where that leaves you