# Initialization of DAE system after PDE discretization
**URL:** https://discourse.julialang.org/t/initialization-of-dae-system-after-pde-discretization/125633
**Category:** Modelling & Simulations
**Created:** [February 6, 2025, 8:00pm UTC](https://discourse.julialang.org/t/initialization-of-dae-system-after-pde-discretization/125633 "2025-02-06T20:00:42Z")
**Posts on this page:** 2
**Page:** 1
### Author:  [@oswaldo](https://discourse.julialang.org/u/oswaldo)
#### Post date: [February 6, 2025, 8:00pm UTC](https://discourse.julialang.org/t/initialization-of-dae-system-after-pde-discretization/125633/1 "2025-02-06T20:00:42Z")
Hi, I’m solving a PDE system using ModelingToolkit.jl, after defining variables, parameters and equations I do
```julia
@named adsmodel = PDESystem(eq,bcs,domains,[z,t],[cN₂(z,t),cH₂(z,t),cNH₃(z,t),qNH₃(z,t),Tg(z,t),Tw(z,t),P(t),v(z,t)],
[De1,De2,De3,Cpg,MTC,P0,α1,α2,α3,α4,β1,β2,λe,tpr,Cv];defaults = pars)
```
Then I apply discretization using MOL as follows:
```julia
N = 30
dz = (z_max - z_min)/N
discretization = MOLFiniteDifference([z => dz],t;advection_scheme = UpwindScheme())
prob = discretize(adsmodel,discretization)
```
However when I try to solve the system
```julia
solads = solve(prob,Rodas5(),reltol=1e-8,abstol=1e-8)
```
I get `Initial Failure`, I’ve tried different solvers compatible with Mass matrix definition but I keep getting the same results. I would like to try with different initialization algorithms using the argument `initializealg` as described [here](https://docs.sciml.ai/DiffEqDocs/latest/solvers/dae_solve/) but I do not know how and where in my code. Thanks
---
### Author:  [@ChrisRackauckas](https://discourse.julialang.org/u/ChrisRackauckas)
#### Post date: [February 6, 2025, 9:29pm UTC](https://discourse.julialang.org/t/initialization-of-dae-system-after-pde-discretization/125633/2 "2025-02-06T21:29:27Z")
Open an issue on MethodOfLines.jl