# Is MonteCarloProblem() still working at present?

**URL:** <https://discourse.julialang.org/t/is-montecarloproblem-still-working-at-present/101292>\
**Category:** Package Management\
**Tags:** question, package, diffeq\
**Created:** [July 7, 2023, 6:17am UTC](https://discourse.julialang.org/t/is-montecarloproblem-still-working-at-present/101292 "2023-07-07T06:17:16Z")\
**Posts on this page:** 3\
**Page:** 1

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**Author:** ![maurice\_lin](https://sea2.discourse-cdn.com/julialang/user_avatar/discourse.julialang.org/maurice_lin/32/51333_2.png) [@maurice\_lin](https://discourse.julialang.org/u/maurice_lin)\
**Post date:** [July 7, 2023, 6:17am UTC](https://discourse.julialang.org/t/is-montecarloproblem-still-working-at-present/101292/1 "2023-07-07T06:17:16Z")

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From [mathematical optimization - Parameter estimation of multiple datasets in julia DifferentialEquations - Stack Overflow](https://stackoverflow.com/questions/50840636/parameter-estimation-of-multiple-datasets-in-julia-differentialequations), I tried the example in Julia. But Julia told me that MonteCarlo function have not been defined.

The function for Monte Carlo problems is strange and bugs are coming over and over again. First I tried to add “DiffEqMonteCarlo, DiffEqBase, DiffEqParamEstim”, and I also created a new personal environment to prevent the conflict between certain packages. But I don’t know why Julia also tells me that “ERROR: UndefVarError: MonteCarloProblem not defined”.

So if this function is out fo date? Or is there a alternative function to deal with problems like what is in the link?

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**Author:** ![mrufsvold](https://sea2.discourse-cdn.com/julialang/user_avatar/discourse.julialang.org/mrufsvold/32/31600_2.png) [@mrufsvold](https://discourse.julialang.org/u/mrufsvold)\
**Post date:** [July 7, 2023, 10:24am UTC](https://discourse.julialang.org/t/is-montecarloproblem-still-working-at-present/101292/2 "2023-07-07T10:24:47Z")

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Can you try:

```julia
julia> using DifferentialEquations
julia> MonteCarloProblem

```

It should print out something like “Generic function with N methods”

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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:** [July 7, 2023, 10:31am UTC](https://discourse.julialang.org/t/is-montecarloproblem-still-working-at-present/101292/3 "2023-07-07T10:31:26Z")

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DiffEqMonteCarlo was removed about 5 years ago (it was pre Julia v1.0) and replaced with the ensemble interface. For details, see:

[https://docs.sciml.ai/DiffEqDocs/stable/features/ensemble/](https://docs.sciml.ai/DiffEqDocs/stable/features/ensemble/)

It’s very similar, with a few extensions.