# Simulating a PID in a DAE - how to simulate a DDAE?

**URL:** <https://discourse.julialang.org/t/simulating-a-pid-in-a-dae-how-to-simulate-a-ddae/111320>\
**Category:** Modelling & Simulations\
**Created:** [March 7, 2024, 7:53pm UTC](https://discourse.julialang.org/t/simulating-a-pid-in-a-dae-how-to-simulate-a-ddae/111320 "2024-03-07T19:53:03Z")\
**Posts on this page:** 1\
**Showing post:** 5

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**Author:** ![lpz18](https://avatars.discourse-cdn.com/v4/letter/l/ec9cab/32.png) [@lpz18](https://discourse.julialang.org/u/lpz18)\
**Post date:** [March 11, 2024, 6:16pm UTC](https://discourse.julialang.org/t/simulating-a-pid-in-a-dae-how-to-simulate-a-ddae/111320/5 "2024-03-11T18:16:45Z")

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I used the example of the SIR model I linked above and a vector of constant lags summed over like in [this example](https://discourse.julialang.org/t/integro-differential-equations-with-differentialequations-jl/19265)

I am not sure what you mean by `Ix = Integral(x)`. I searched in the DifferentialEquations docs and github page and can’t find anything like that. The closest thing I found was Integrals.jl, but it doesn’t seem to have any examples that use DEs.

If you meant something specitic, then I would appreciate clarification. Otherwise, I have a working solution now.

thanks for your help

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