# Problem about SDDE solver in differentialequation.jl

**URL:** <https://discourse.julialang.org/t/problem-about-sdde-solver-in-differentialequation-jl/67495>\
**Category:** General Usage\
**Tags:** differentialequation\
**Created:** [September 1, 2021, 11:52am UTC](https://discourse.julialang.org/t/problem-about-sdde-solver-in-differentialequation-jl/67495 "2021-09-01T11:52:59Z")\
**Posts on this page:** 2\
**Page:** 1

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**Author:** ![Liwei17](https://sea2.discourse-cdn.com/julialang/user_avatar/discourse.julialang.org/liwei17/32/28423_2.png) [@Liwei17](https://discourse.julialang.org/u/Liwei17)\
**Post date:** [September 1, 2021, 11:52am UTC](https://discourse.julialang.org/t/problem-about-sdde-solver-in-differentialequation-jl/67495/1 "2021-09-01T11:52:59Z")

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Basically, I’m running a SDDE solver.

`tspan = (0, 50000); prob = SDDEProblem(f, g, u0, h, tspan, p; constant_lags = lag); sol = solve(prob, RKMil());`

I want to get the corresponding tspan time point in “sol”.  
But I found that the size of “sol” is different for every run, so I can’t get the corresponding time point by simply times “size(tspan)[2] / size(sol)[2]”.

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<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:** [September 1, 2021, 12:13pm UTC](https://discourse.julialang.org/t/problem-about-sdde-solver-in-differentialequation-jl/67495/2 "2021-09-01T12:13:47Z")

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It’s an adaptive solver on a stochastic equation so it can take a different number of steps each time. Do `saveat=0.1` for example if you want to make it save at constant steps.