# What is DiffEqBase.NoRootFind?

**URL:** <https://discourse.julialang.org/t/what-is-diffeqbase-norootfind/91223>\
**Category:** New to Julia\
**Tags:** question, package\
**Created:** [December 4, 2022, 6:28pm UTC](https://discourse.julialang.org/t/what-is-diffeqbase-norootfind/91223 "2022-12-04T18:28:20Z")\
**Posts on this page:** 3\
**Page:** 1

<div class="post-metadata">

**Author:** ![Luigi\_Marongiu](https://sea2.discourse-cdn.com/julialang/user_avatar/discourse.julialang.org/luigi_marongiu/32/7909_2.png) [@Luigi\_Marongiu](https://discourse.julialang.org/u/Luigi_Marongiu)\
**Post date:** [December 4, 2022, 6:28pm UTC](https://discourse.julialang.org/t/what-is-diffeqbase-norootfind/91223/1 "2022-12-04T18:28:20Z")

</div>

Hello,  
I have inherited some code to solve ODE and there is a line containing:

```julia
julia> make_callback(t, v) = PresetTimeCallback([t], (i) -> ( i.u[end] += v))
make_callback (generic function with 1 method)

julia> no_affect!(integrator) = nothing
no_affect! (generic function with 1 method)

julia> condition_1(u, t, integrator) = u[1]-1
condition_1 (generic function with 1 method)

julia> affect_1!(integrator) = integrator.u[1] = 0.0
affect_1! (generic function with 1 method)

julia> ContinuousCallback(condition_1, no_affect!, affect_1!, 
           rootfind = DiffEqBase.NoRootFind)
ERROR: UndefVarError: NoRootFind not defined
Stacktrace:
 [1] getproperty(x::Module, f::Symbol)
   @ Base ./Base.jl:31
 [2] top-level scope
   @ none:1

```

I have loaded `using DifferentialEquations, DiffEqBase` but, given the error, it is probably not enough.  
What package contains NoRootFind?  
Thank you

---

<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:** [December 4, 2022, 9:27pm UTC](https://discourse.julialang.org/t/what-is-diffeqbase-norootfind/91223/2 "2022-12-04T21:27:42Z")

</div>

` SciMLBase.NoRootFind`, as mentioned in the documentation.

[https://docs.sciml.ai/DiffEqDocs/stable/features/callback\_functions/#ContinuousCallback](https://docs.sciml.ai/DiffEqDocs/stable/features/callback_functions/#ContinuousCallback)

But you probably shouldn’t be using that in most cases. In most cases, if you’re disabling rootfinding then you probably want to be using a `DiscreteCallback`.

---

<div class="post-metadata">

**Author:** ![Luigi\_Marongiu](https://sea2.discourse-cdn.com/julialang/user_avatar/discourse.julialang.org/luigi_marongiu/32/7909_2.png) [@Luigi\_Marongiu](https://discourse.julialang.org/u/Luigi_Marongiu)\
**Post date:** [December 5, 2022, 5:43am UTC](https://discourse.julialang.org/t/what-is-diffeqbase-norootfind/91223/3 "2022-12-05T05:43:40Z")

</div>

which is what i was using before. Thank you, I’ll try to fix the code. Cheers