# JumpProcesses.jl solvers

**URL:** <https://discourse.julialang.org/t/jumpprocesses-jl-solvers/121883>\
**Category:** Performance\
**Created:** [October 28, 2024, 4:37pm UTC](https://discourse.julialang.org/t/jumpprocesses-jl-solvers/121883 "2024-10-28T16:37:35Z")\
**Posts on this page:** 5\
**Page:** 1

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**Author:** ![hhindley](https://sea2.discourse-cdn.com/julialang/user_avatar/discourse.julialang.org/hhindley/32/207751_2.png) [@hhindley](https://discourse.julialang.org/u/hhindley)\
**Post date:** [October 28, 2024, 4:37pm UTC](https://discourse.julialang.org/t/jumpprocesses-jl-solvers/121883/1 "2024-10-28T16:37:35Z")

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I’m modelling a biochemical system using JumpProcesses.jl. I am coupling a continuous ODE to a jumpset which includes MassActionJumps, ConstantRateJumps and unbounded VariableRateJumps.

When I increase my tspan, or in certain parameter conditions I hit MaxIters. This system is stiff and when I solve this system deterministically I use Rodas4. I can’t see options to use anything other than Tsit5 when solving a jump problem which includes unbounded variable rate jumps, but Tsit5 is a solver for non-stiff problems, so I’m wondering if this is why I’m hitting MaxIters.

Ideally I’d like a solution that avoids having to increase the MaxIters to keep computation time down. Any tips on this would be much appreciated.

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**Author:** ![ChrisRackauckas](https://sea2.discourse-cdn.com/julialang/user_avatar/discourse.julialang.org/chrisrackauckas/32/77_2.png) [@ChrisRackauckas](https://discourse.julialang.org/u/ChrisRackauckas)\
**Post date:** [October 28, 2024, 5:44pm UTC](https://discourse.julialang.org/t/jumpprocesses-jl-solvers/121883/2 "2024-10-28T17:44:58Z")

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> [@hhindley](#):
>
> I can’t see options to use anything other than Tsit5 when solving a jump problem which includes unbounded variable rate jumps, but Tsit5 is a solver for non-stiff problems, so I’m wondering if this is why I’m hitting MaxIters.

All of the ODE solvers can be used.

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**Author:** ![hhindley](https://sea2.discourse-cdn.com/julialang/user_avatar/discourse.julialang.org/hhindley/32/207751_2.png) [@hhindley](https://discourse.julialang.org/u/hhindley)\
**Post date:** [October 28, 2024, 5:54pm UTC](https://discourse.julialang.org/t/jumpprocesses-jl-solvers/121883/3 "2024-10-28T17:54:07Z")

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Thanks, I thought that would be the case, I get this error when trying to use any other solver than Tsit5 - ERROR: MethodError: no method matching strides(::ExtendedJumpArray{Float64, 1, Vector{Float64}, Vector{Float64}}). Do you have any suggestions as to what could be causing that?

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**Author:** ![isaacsas](https://avatars.discourse-cdn.com/v4/letter/i/f6c823/32.png) [@isaacsas](https://discourse.julialang.org/u/isaacsas)\
**Post date:** [October 28, 2024, 6:47pm UTC](https://discourse.julialang.org/t/jumpprocesses-jl-solvers/121883/4 "2024-10-28T18:47:01Z")

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It’s a missing dispatch for `ExtendedJumpArray`s which are what is used with `VariableRateJump`s. I opened a related issue on JumpProcesses: [ODE-jump models with implicit solvers not working · Issue #459 · SciML/JumpProcesses.jl · GitHub](https://github.com/SciML/JumpProcesses.jl/issues/459), but if you could add a short example that illustrates the error you get that would be helpful to us.

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**Author:** ![ChrisRackauckas](https://sea2.discourse-cdn.com/julialang/user_avatar/discourse.julialang.org/chrisrackauckas/32/77_2.png) [@ChrisRackauckas](https://discourse.julialang.org/u/ChrisRackauckas)\
**Post date:** [October 28, 2024, 7:05pm UTC](https://discourse.julialang.org/t/jumpprocesses-jl-solvers/121883/5 "2024-10-28T19:05:29Z")

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Okay yeah that’s a bug but shouldn’t be hard to fix.