Hi,

I am new user of Julia and I want to use it for solving PDEs and ODEs numerically. I am trying to run examples that are available in Julia website or GitHub but I get error.

For instance I want to run this example:

```
using OrdinaryDiffEq, ModelingToolkit, DiffEqOperators
# Method of Manufactured Solutions: exact solution
u_exact = (x,t) -> exp.(-t) * cos.(x)
# 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))
bcs = [u(0,x) ~ cos(x),
u(t,0) ~ exp(-t),
u(t,1) ~ exp(-t) * cos(1)]
# Space and time domains
domains = [t ∈ IntervalDomain(0.0,1.0),
x ∈ IntervalDomain(0.0,1.0)]
# PDE system
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=0.2)
# Plot results and compare with exact solution
x = (0:dx:1)[2:end-1]
t = sol.t
using Plots
plt = plot()
for i in 1:length(t)
plot!(x,sol.u[i],label="Numerical, t=$(t[i])")
scatter!(x, u_exact(x, t[i]),label="Exact, t=$(t[i])")
end
display(plt)
savefig("plot.png")
```

But I get this error:

UndefKeywordError: keyword argument name not assigned

Stacktrace:

[1] PDESystem(eqs::Equation, bcs::Vector{Equation}, domain::Vector{Symbolics.VarDomainPairing}, ivs::Vector{Num}, dvs::Vector{Num}, ps::SciMLBase.NullParameters) (repeats 2 times)

@ ModelingToolkit C:\Users\rm18124.julia\packages\ModelingToolkit\57XKa\src\systems\pde\pdesystem.jl:75

[2] top-level scope

@ In[32]:22

[3] eval

@ .\boot.jl:373 [inlined]

[4] include_string(mapexpr::typeof(REPL.softscope), mod::Module, code::String, filename::String)

@ Base .\loading.jl:1196

I double checked the PDESystem and it looks fine, any help please?

Thanks