# Using solution of DDE model as history for another (larger) DDE problem

**URL:** https://discourse.julialang.org/t/using-solution-of-dde-model-as-history-for-another-larger-dde-problem/102435
**Category:** Numerics
**Tags:** question, diffeq, differentialequation
**Created:** [August 3, 2023, 7:43am UTC](https://discourse.julialang.org/t/using-solution-of-dde-model-as-history-for-another-larger-dde-problem/102435 "2023-08-03T07:43:51Z")
**Posts on this page:** 1
**Showing post:** 2

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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: [August 5, 2023, 10:56pm UTC](https://discourse.julialang.org/t/using-solution-of-dde-model-as-history-for-another-larger-dde-problem/102435/2 "2023-08-05T22:56:41Z")

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> [@jewh](#):
>
> However it is not clear to me how to use the output of `solve(prob, alg)` to define the history function `h(p, t)` to achieve this, as `solve` returns a vector with (often) variable timesteps between values.

The output of `solve` is a `sol(t)` function so `h(p,t) = sol(t)` just works.

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