# DifferentialEquations.jl Mass Matrix DAE Explicit
**URL:** https://discourse.julialang.org/t/differentialequations-jl-mass-matrix-dae-explicit/129447
**Category:** Modelling & Simulations
**Tags:** question
**Created:** [May 29, 2025, 7:07pm UTC](https://discourse.julialang.org/t/differentialequations-jl-mass-matrix-dae-explicit/129447 "2025-05-29T19:07:54Z")
**Posts on this page:** 4
**Page:** 1
### Author:  [@ziolai](https://discourse.julialang.org/u/ziolai)
#### Post date: [May 29, 2025, 7:07pm UTC](https://discourse.julialang.org/t/differentialequations-jl-mass-matrix-dae-explicit/129447/1 "2025-05-29T19:07:55Z")
Are any of the methods listed at [Mass Matrix and Fully Implicit DAE Solvers · DifferentialEquations.jl](https://docs.sciml.ai/DiffEqDocs/stable/solvers/dae_solve/) explicit in time, and therefore **not** require a Jacobian?
Reason for asking is that solving time-dependent Stokes flow using Ferrite renders use of AD to generate the Jacobian hard.
A MWE is at [finite\_element\_electrical\_engineering/project-based-assignment/metal-hydride-storage/notebooks/stokes\_2d\_channel\_quad\_transient.ipynb at main · ziolai/finite\_element\_electrical\_engineering · GitHub](https://github.com/ziolai/finite_element_electrical_engineering/blob/main/project-based-assignment/metal-hydride-storage/notebooks/stokes_2d_channel_quad_transient.ipynb)
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### Author:  [@Oscar\_Smith](https://discourse.julialang.org/u/Oscar_Smith)
#### Post date: [May 29, 2025, 7:55pm UTC](https://discourse.julialang.org/t/differentialequations-jl-mass-matrix-dae-explicit/129447/2 "2025-05-29T19:55:22Z")
No. Explicit methods are incapable of solving DAEs.
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### Author:  [@ziolai](https://discourse.julialang.org/u/ziolai)
#### Post date: [May 29, 2025, 8:00pm UTC](https://discourse.julialang.org/t/differentialequations-jl-mass-matrix-dae-explicit/129447/3 "2025-05-29T20:00:57Z")
Clear. Thx. I guessed so much. Can we plunk in an alternative to AD (finite differences?) to compute the derivatives?
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### Author:  [@Oscar\_Smith](https://discourse.julialang.org/u/Oscar_Smith)
#### Post date: [May 29, 2025, 8:07pm UTC](https://discourse.julialang.org/t/differentialequations-jl-mass-matrix-dae-explicit/129447/4 "2025-05-29T20:07:25Z")
yeah, instead of `sol = solve(prob_mm, Rodas5(), reltol = 1e-8, abstol = 1e-8)`, you want
```julia
using ADTypes
sol = solve(prob_mm, Rodas5P(autodiff=AutoFiniteDiff()), reltol = 1e-8, abstol = 1e-8)
```