ERROR: type Array has no field lhs for Schrodinger equation

[BearBearCodes]

Hi, I'm following the heat equation tutorial as a starting point for solving the Schrodinger equation, but I'm getting the following error (in WSL2 running Ubuntu 20.04.5 LTS):

type Array has no field lhs

Stacktrace:
  [1] getproperty
    @ [./Base.jl:37](https://vscode-remote+wsl-002bubuntu.vscode-resource.vscode-cdn.net/mnt/c/Users/ichen/OneDrive/Documents/Jobs/WaterlooWorks/3B_Jobs/S2023/CnuB-mirror/notebooks/Base.jl:37) [inlined]
  [2] (::PDEBase.var"#118#119"{typeof(identity)})(eq::Vector{Equation})
    @ PDEBase [~/.julia/packages/PDEBase/2OwkC/src/make_pdesys_compatible.jl:20](https://vscode-remote+wsl-002bubuntu.vscode-resource.vscode-cdn.net/mnt/c/Users/ichen/OneDrive/Documents/Jobs/WaterlooWorks/3B_Jobs/S2023/CnuB-mirror/notebooks/~/.julia/packages/PDEBase/2OwkC/src/make_pdesys_compatible.jl:20)
  [3] iterate
    @ [./generator.jl:47](https://vscode-remote+wsl-002bubuntu.vscode-resource.vscode-cdn.net/mnt/c/Users/ichen/OneDrive/Documents/Jobs/WaterlooWorks/3B_Jobs/S2023/CnuB-mirror/notebooks/generator.jl:47) [inlined]
  [4] collect_to!(dest::Vector{Equation}, itr::Base.Generator{Vector{Any}, PDEBase.var"#118#119"{typeof(identity)}}, offs::Int64, st::Int64)
    @ Base [./array.jl:840](https://vscode-remote+wsl-002bubuntu.vscode-resource.vscode-cdn.net/mnt/c/Users/ichen/OneDrive/Documents/Jobs/WaterlooWorks/3B_Jobs/S2023/CnuB-mirror/notebooks/array.jl:840)
  [5] collect_to_with_first!(dest::Vector{Equation}, v1::Equation, itr::Base.Generator{Vector{Any}, PDEBase.var"#118#119"{typeof(identity)}}, st::Int64)
    @ Base [./array.jl:818](https://vscode-remote+wsl-002bubuntu.vscode-resource.vscode-cdn.net/mnt/c/Users/ichen/OneDrive/Documents/Jobs/WaterlooWorks/3B_Jobs/S2023/CnuB-mirror/notebooks/array.jl:818)
  [6] _collect(c::Vector{Any}, itr::Base.Generator{Vector{Any}, PDEBase.var"#118#119"{typeof(identity)}}, #unused#::Base.EltypeUnknown, isz::Base.HasShape{1})
    @ Base [./array.jl:812](https://vscode-remote+wsl-002bubuntu.vscode-resource.vscode-cdn.net/mnt/c/Users/ichen/OneDrive/Documents/Jobs/WaterlooWorks/3B_Jobs/S2023/CnuB-mirror/notebooks/array.jl:812)
  [7] collect_similar
    @ [./array.jl:711](https://vscode-remote+wsl-002bubuntu.vscode-resource.vscode-cdn.net/mnt/c/Users/ichen/OneDrive/Documents/Jobs/WaterlooWorks/3B_Jobs/S2023/CnuB-mirror/notebooks/array.jl:711) [inlined]
  [8] map
    @ [./abstractarray.jl:3261](https://vscode-remote+wsl-002bubuntu.vscode-resource.vscode-cdn.net/mnt/c/Users/ichen/OneDrive/Documents/Jobs/WaterlooWorks/3B_Jobs/S2023/CnuB-mirror/notebooks/abstractarray.jl:3261) [inlined]
  [9] apply_lhs_rhs(f::typeof(identity), eqs::Vector{Any})
    @ PDEBase [~/.julia/packages/PDEBase/2OwkC/src/make_pdesys_compatible.jl:19](https://vscode-remote+wsl-002bubuntu.vscode-resource.vscode-cdn.net/mnt/c/Users/ichen/OneDrive/Documents/Jobs/WaterlooWorks/3B_Jobs/S2023/CnuB-mirror/notebooks/~/.julia/packages/PDEBase/2OwkC/src/make_pdesys_compatible.jl:19)
 [10] make_pdesys_compatible(pdesys::PDESystem)
    @ PDEBase [~/.julia/packages/PDEBase/2OwkC/src/make_pdesys_compatible.jl:41](https://vscode-remote+wsl-002bubuntu.vscode-resource.vscode-cdn.net/mnt/c/Users/ichen/OneDrive/Documents/Jobs/WaterlooWorks/3B_Jobs/S2023/CnuB-mirror/notebooks/~/.julia/packages/PDEBase/2OwkC/src/make_pdesys_compatible.jl:41)
 [11] symbolic_discretize(pdesys::PDESystem, discretization::MOLFiniteDifference{MethodOfLines.CenterAlignedGrid, MethodOfLines.ScalarizedDiscretization})
    @ PDEBase [~/.julia/packages/PDEBase/2OwkC/src/symbolic_discretize.jl:10](https://vscode-remote+wsl-002bubuntu.vscode-resource.vscode-cdn.net/mnt/c/Users/ichen/OneDrive/Documents/Jobs/WaterlooWorks/3B_Jobs/S2023/CnuB-mirror/notebooks/~/.julia/packages/PDEBase/2OwkC/src/symbolic_discretize.jl:10)
 [12] discretize(pdesys::PDESystem, discretization::MOLFiniteDifference{MethodOfLines.CenterAlignedGrid, MethodOfLines.ScalarizedDiscretization}; analytic::Nothing, kwargs::Base.Pairs{Symbol, Union{}, Tuple{}, NamedTuple{(), Tuple{}}})
    @ PDEBase [~/.julia/packages/PDEBase/2OwkC/src/discretization_state.jl:58](https://vscode-remote+wsl-002bubuntu.vscode-resource.vscode-cdn.net/mnt/c/Users/ichen/OneDrive/Documents/Jobs/WaterlooWorks/3B_Jobs/S2023/CnuB-mirror/notebooks/~/.julia/packages/PDEBase/2OwkC/src/discretization_state.jl:58)
 [13] discretize(pdesys::PDESystem, discretization::MOLFiniteDifference{MethodOfLines.CenterAlignedGrid, MethodOfLines.ScalarizedDiscretization})
    @ PDEBase [~/.julia/packages/PDEBase/2OwkC/src/discretization_state.jl:55](https://vscode-remote+wsl-002bubuntu.vscode-resource.vscode-cdn.net/mnt/c/Users/ichen/OneDrive/Documents/Jobs/WaterlooWorks/3B_Jobs/S2023/CnuB-mirror/notebooks/~/.julia/packages/PDEBase/2OwkC/src/discretization_state.jl:55)
 [14] top-level scope
    @ /mnt/c/Users/ichen/OneDrive/Documents/Jobs/WaterlooWorks/3B_Jobs/S2023/CnuB-mirror/notebooks/julia_warmup.ipynb:27

I've looked at #117, but that fix doesn't apply in my case. I suspect there is a simple fix (see MWE below), but I'm not quite sure what is happening.

---

MWE (most of the code is directly copy-pasted from the heat equation tutorial):

using OrdinaryDiffEq, ModelingToolkit, MethodOfLines, DomainSets
# Parameters, variables, and derivatives
@parameters t x
@variables u(..)
Dt = Differential(t)
Dxx = Differential(x)^2

# 1D PDE and boundary conditions
eq = Dt(u(t, x)) ~ Dxx(u(t, x)) * (1im / 2)
bcs = [u(0, x) ~ exp(1im * x),
    u(t, 0) ~ exp(-1im * t),
    u(t, 1) ~ exp(1im * (1 - t))]

# Space and time domains
domains = [t ∈ Interval(0.0, 1.0),
    x ∈ Interval(0.0, 1.0)]

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

# Method of lines discretization
dx = 0.1
order = 2
discretization = MOLFiniteDifference([x => dx], t)

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

# Solve ODE problem
using OrdinaryDiffEq
sol = solve(prob, Tsit5(), saveat=0.5)

# Plot results
discrete_x = sol[x]
discrete_t = sol[t]
solu = sol[u(t, x)]

using Plots
plt = plot()

for i in 1:length(discrete_t)
    plot!(discrete_x, solu[i, :], label="Numerical, t=$(discrete_t[i])")
end
display(plt)

[xtalax]

I'm afraid complex numbers are still unsupported, There is an open PR but we are waiting for stuff to be merged upstream.

[BearBearCodes]

Oh I see. Thanks for the quick reply! I'll keep an eye out for updates to #58 (comment)