# Are there any examples of DiscreteProblem usage?

**URL:** <https://discourse.julialang.org/t/are-there-any-examples-of-discreteproblem-usage/134618>\
**Category:** New to Julia\
**Tags:** differentialequation\
**Created:** [December 17, 2025, 6:10pm UTC](https://discourse.julialang.org/t/are-there-any-examples-of-discreteproblem-usage/134618 "2025-12-17T18:10:23Z")\
**Posts on this page:** 1\
**Showing post:** 3

<div class="post-metadata">

**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:** [December 18, 2025, 12:11pm UTC](https://discourse.julialang.org/t/are-there-any-examples-of-discreteproblem-usage/134618/3 "2025-12-18T12:11:35Z")

</div>

There is a lot of random stuff around. For example

```julia-auto
using OrdinaryDiffEqFunctionMap
  function henon_map!(u_next, u, p, t)                                                                                                                                                                              
      u_next[1] = 1 + u[2] - 1.4 * u[1]^2                                                                                                                                                                           
      u_next[2] = 0.3 * u[1]                                                                                                                                                                                        
  end                                                                                                                                                                                                               
  prob = DiscreteProblem(henon_map!, [0.5, 0.5], (0, 100))                                                                                                                                                          
  sol = solve(prob, FunctionMap())

```

> [@Time-varying parameter specification in DiscreteProblem?](https://discourse.julialang.org/t/time-varying-parameter-specification-in-discreteproblem/116975):
>
> I have a simple DiscreteProblem, based on the SIR epidemic model. I’d like to pass a time-varying parameter to the model, to reduce \beta by a factor v(t). As this is a discrete-time map, I’d like to define v as a vector and just retrieve value at a discrete-time index, as DataInterpolations.jl seems like overkill. Any suggestions on how best to implement this? using OrdinaryDiffEq using Plots @inline function rate\_to\_proportion(r::Float64,t::Float64) 1-exp(-r\*t) end function sir\_map!(unp…

> <https://github.com/epirecipes/sir-julia/blob/master/markdown/markov/markov.md>

> **[Open Circular Port Graph Examples · AlgebraicDynamics.jl](https://algebraicjulia.github.io/AlgebraicDynamics.jl/dev/examples/CPG_examples/)**
>
> Documentation for AlgebraicDynamics.jl.

> **[Simple Poisson Processes in JumpProcesses · JumpProcesses.jl](https://docs.sciml.ai/JumpProcesses/stable/tutorials/simple_poisson_process/)**
>
> Documentation for JumpProcesses.jl.

What exactly are you looking to do?

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