# How to use "Callback" while solving differential equation with uncertain initial condition and uncertain parameters?

**URL:** <https://discourse.julialang.org/t/how-to-use-callback-while-solving-differential-equation-with-uncertain-initial-condition-and-uncertain-parameters/96801>\
**Category:** General Usage\
**Tags:** question, package\
**Created:** [March 29, 2023, 7:52pm UTC](https://discourse.julialang.org/t/how-to-use-callback-while-solving-differential-equation-with-uncertain-initial-condition-and-uncertain-parameters/96801 "2023-03-29T19:52:49Z")\
**Posts on this page:** 1\
**Page:** 1

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**Author:** ![Ashu](https://avatars.discourse-cdn.com/v4/letter/a/4bbf92/32.png) [@Ashu](https://discourse.julialang.org/u/Ashu)\
**Post date:** [March 29, 2023, 7:52pm UTC](https://discourse.julialang.org/t/how-to-use-callback-while-solving-differential-equation-with-uncertain-initial-condition-and-uncertain-parameters/96801/1 "2023-03-29T19:52:49Z")

</div>

Hello all,

I am solving nonlinear differential equation using “ReachabilityAnalysis.jl” package (Example: [Lotka-Volterra · ReachabilityAnalysis.jl](https://juliareach.github.io/ReachabilityAnalysis.jl/dev/generated_examples/LotkaVolterra/)). Both initial condition and parameters are uncertain, so I tool intervals of parameters. I wish to check the sensitivity of the system against the perturbation in parameters. To check that I perturb the parameters’ intervals in between the simulation time. Please let me know how to do that using “Callback” function (Example of callback: [Event Handling and Callback Functions · DifferentialEquations.jl](https://docs.sciml.ai/DiffEqDocs/stable/features/callback_functions/#ContinuousCallback-Examples)).

Thank you