# Does anyone know how to retrieve the number of generated cuts in the informational callback?

**URL:** <https://discourse.julialang.org/t/does-anyone-know-how-to-retrieve-the-number-of-generated-cuts-in-the-informational-callback/15370>\
**Category:** Optimization (Mathematical)\
**Tags:** question\
**Created:** [September 23, 2018, 9:48am UTC](https://discourse.julialang.org/t/does-anyone-know-how-to-retrieve-the-number-of-generated-cuts-in-the-informational-callback/15370 "2018-09-23T09:48:39Z")\
**Posts on this page:** 10\
**Page:** 1

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**Author:** ![CBongiova](https://sea2.discourse-cdn.com/julialang/user_avatar/discourse.julialang.org/cbongiova/32/4856_2.png) [@CBongiova](https://discourse.julialang.org/u/CBongiova)\
**Post date:** [September 23, 2018, 9:48am UTC](https://discourse.julialang.org/t/does-anyone-know-how-to-retrieve-the-number-of-generated-cuts-in-the-informational-callback/15370/1 "2018-09-23T09:48:39Z")

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Hi,

I would like to retrieve the information contained at the end of the Gurobi log (the summary section [MIP Logging](http://www.gurobi.com/documentation/8.0/refman/mip_logging.html))

In particular, I am interested in saving the number of cuts applied to my MIP (MIP\_CUTCNT : [http://www.gurobi.com/documentation/8.0/refman/callback\_codes.html#sec:CallbackCodes](http://www.gurobi.com/documentation/8.0/refman/callback_codes.html#sec:CallbackCodes)).  
I couldn’t find a way to retrieve this information with cbget in MathProgbase.

Does anyone know how to do it?

Thanks!

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<div class="post-metadata">

**Author:** ![miles.lubin](https://sea2.discourse-cdn.com/julialang/user_avatar/discourse.julialang.org/miles.lubin/32/279_2.png) [@miles.lubin](https://discourse.julialang.org/u/miles.lubin)\
**Post date:** [September 23, 2018, 2:45pm UTC](https://discourse.julialang.org/t/does-anyone-know-how-to-retrieve-the-number-of-generated-cuts-in-the-informational-callback/15370/2 "2018-09-23T14:45:02Z")

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This doesn’t appear to be wrapped at the MathProgBase level in Gurobi.jl, but following the example of `cbgetmipsolution` ([Gurobi.jl/MPBWrapper.jl at 120d606da08facffb206d73d932dbb0bf7d7001d · jump-dev/Gurobi.jl · GitHub](https://github.com/JuliaOpt/Gurobi.jl/blob/120d606da08facffb206d73d932dbb0bf7d7001d/src/MPBWrapper.jl#L570)) you could write a similar wrapper that calls `Gurobi.cbget_mip_cutcnt`. I don’t have a Gurobi license so I can’t test this.

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<div class="post-metadata">

**Author:** ![CBongiova](https://sea2.discourse-cdn.com/julialang/user_avatar/discourse.julialang.org/cbongiova/32/4856_2.png) [@CBongiova](https://discourse.julialang.org/u/CBongiova)\
**Post date:** [September 24, 2018, 11:23am UTC](https://discourse.julialang.org/t/does-anyone-know-how-to-retrieve-the-number-of-generated-cuts-in-the-informational-callback/15370/3 "2018-09-24T11:23:19Z")

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Thanks for your reply. I will try to write the wrapper for the mip\_cutcnt myself.  
Question: Can I just locally modify the MPBWrapper.jl function on my computer?

Considering the quite simple addition to MPBWrapper.jl and the relevance of such addition for the Julia/JuMP users implementing callback functions, I believe it would be nice to just add the wrapper to MathProgBase. Is this something you would consider?

As for the Gurobi licence, I think you can get a size-limited gurobi licence for free ([Software Downloads and License Center - Gurobi](http://www.gurobi.com/downloads/download-center)).

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<div class="post-metadata">

**Author:** ![odow](https://sea2.discourse-cdn.com/julialang/user_avatar/discourse.julialang.org/odow/32/28685_2.png) [@odow](https://discourse.julialang.org/u/odow)\
**Post date:** [September 24, 2018, 1:56pm UTC](https://discourse.julialang.org/t/does-anyone-know-how-to-retrieve-the-number-of-generated-cuts-in-the-informational-callback/15370/4 "2018-09-24T13:56:31Z")

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> Can I just locally modify the MPBWrapper.jl function on my computer?

Yes.

> Is this something you would consider?

Yes! Have a look at the [contributing guide](https://github.com/JuliaOpt/JuMP.jl/blob/master/CONTRIBUTING.md#contribute-code-to-jump) (just replace any references to JuMP with Gurobi.jl).

If you’re not sure how to make a pull request: implement the wrapper locally, test that it works, then [open an issue on the Gurobi.jl page](https://github.com/JuliaOpt/Gurobi.jl/issues/new), post the code you want to add, and we’ll walk you through the process.

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<div class="post-metadata">

**Author:** ![CBongiova](https://sea2.discourse-cdn.com/julialang/user_avatar/discourse.julialang.org/cbongiova/32/4856_2.png) [@CBongiova](https://discourse.julialang.org/u/CBongiova)\
**Post date:** [October 1, 2018, 1:16pm UTC](https://discourse.julialang.org/t/does-anyone-know-how-to-retrieve-the-number-of-generated-cuts-in-the-informational-callback/15370/5 "2018-10-01T13:16:42Z")

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Thanks for your reply.

Actually, implementing the wrapper does not appear to be that straight-forward (or at least not for me).  
Following the example of cbgetmipsolution posted by @miles.lubin, I tried to implement the following in the MPBWrapper.jl :

function cbgetmipcutcnt(d::GurobiCallbackData)  
@assert d.state == :MIPSol  
return cbget\_mip\_cutcnt(d.cbdata, d.where)  
end

function cbgetmipcutcnt(d::GurobiCallbackData,output)  
@assert d.state == :MIPSol  
return cbget\_mip\_cutcnt(d.cbdata, d.where, output)  
end

but then i get the following error when running my code:

 ![Screenshot%20(75)](https://global.discourse-cdn.com/julialang/original/3X/1/c/1c1f27fccd61f5f1e720feeae9f37a43930f5706.png)

Could you please give any hint or help on how to code the wrapper?  
Thanks!

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<div class="post-metadata">

**Author:** ![odow](https://sea2.discourse-cdn.com/julialang/user_avatar/discourse.julialang.org/odow/32/28685_2.png) [@odow](https://discourse.julialang.org/u/odow)\
**Post date:** [October 1, 2018, 3:00pm UTC](https://discourse.julialang.org/t/does-anyone-know-how-to-retrieve-the-number-of-generated-cuts-in-the-informational-callback/15370/6 "2018-10-01T15:00:11Z")

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A few pointers

1. wrap your code in triple-backticks like so

````markdown
    ```julia
    # code goes here
    ```

````

1. copy the text of the error, rather than a screenshot since screenshots are usually really hard to read.
2. Your error says `cbgetmipcutcnt` not defined. That probably means that you changed the Gurobi source file, but didn’t restart Julia (or use something like [https://github.com/timholy/Revise.jl](https://github.com/timholy/Revise.jl)).
3. ~~You need to implement the function `cbget_mip_cutcnt`. This should be as simple as adding a new tuple to the [list in this line](https://github.com/JuliaOpt/Gurobi.jl/blob/120d606da08facffb206d73d932dbb0bf7d7001d/src/grb_callbacks.jl#L142) with the value `(:cbget_mip_cutcnt, XXXX)`, where `XXX` is the callback code you can look up in the Gurobi documentation [http://www.gurobi.com/documentation/7.5/refman/callback\_codes.html#sec:CallbackCodes.](http://www.gurobi.com/documentation/7.5/refman/callback_codes.html#sec:CallbackCodes.)~~ It’s actually already wrapped [Gurobi.jl/grb\_callbacks.jl at 120d606da08facffb206d73d932dbb0bf7d7001d · jump-dev/Gurobi.jl · GitHub](https://github.com/JuliaOpt/Gurobi.jl/blob/120d606da08facffb206d73d932dbb0bf7d7001d/src/grb_callbacks.jl#L110)

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<div class="post-metadata">

**Author:** ![CBongiova](https://sea2.discourse-cdn.com/julialang/user_avatar/discourse.julialang.org/cbongiova/32/4856_2.png) [@CBongiova](https://discourse.julialang.org/u/CBongiova)\
**Post date:** [October 1, 2018, 3:51pm UTC](https://discourse.julialang.org/t/does-anyone-know-how-to-retrieve-the-number-of-generated-cuts-in-the-informational-callback/15370/7 "2018-10-01T15:51:07Z")

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@odow thanks for your help.  
Question: I see that there is a method definition for “mip\_cutcnt”. Does it mean there is a way to call mip\_cutcnt – For example numcuts=cbget\_mip\_cutcnt(cb,Cint(3))? ([Gurobi.jl/grb\_callbacks.jl at 120d606da08facffb206d73d932dbb0bf7d7001d · jump-dev/Gurobi.jl · GitHub](https://github.com/JuliaOpt/Gurobi.jl/blob/120d606da08facffb206d73d932dbb0bf7d7001d/src/grb_callbacks.jl#L110))

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<div class="post-metadata">

**Author:** ![CBongiova](https://sea2.discourse-cdn.com/julialang/user_avatar/discourse.julialang.org/cbongiova/32/4856_2.png) [@CBongiova](https://discourse.julialang.org/u/CBongiova)\
**Post date:** [October 1, 2018, 4:09pm UTC](https://discourse.julialang.org/t/does-anyone-know-how-to-retrieve-the-number-of-generated-cuts-in-the-informational-callback/15370/8 "2018-10-01T16:09:34Z")

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When I try

```julia
#Produce an info callback
bbdata = Vector{Float64}[]
function infocallback(cb)
node = MathProgBase.cbgetexplorednodes(cb)
obj = MathProgBase.cbgetobj(cb)
bestbound = MathProgBase.cbgetbestbound(cb)
gap=(abs(bestbound-obj)/abs(obj))*100
**numcuts=cbget_mip_cutcnt(cb,Cint(3))**
push!(bbdata, [time(), node, obj, bestbound, gap])
end
addinfocallback(m, infocallback, when = :Intermediate)

```

I get the following error:

> MethodError: no method matching cbget\_mip\_cutcnt(::Gurobi.GurobiCallbackData, ::Int32)e[0m  
> Closest candidates are:  
> cbget\_mip\_cutcnt(e[91m::Gurobi.CallbackDatae[39m, ::Int32) at C:\Users\bongiova.julia\v0.6\Gurobi\src\grb\_callbacks.jl:138  
> (::#infocallback#238)(::Gurobi.GurobiCallbackData) at model\_callback\_full.jl:1205  
> infocallback(::Gurobi.GurobiCallbackData, ::JuMP.Model, ::Array{JuMP.InfoCallback,1}) at callbacks.jl:175  
> (::JuMP.##146#147{JuMP.Model,Array{JuMP.InfoCallback,1}})(::Gurobi.GurobiCallbackData) at callbacks.jl:192  
> mastercallback(::Ptr{Void}, ::Ptr{Void}, ::Int32, ::Ptr{Void}) at MPBWrapper.jl:695  
> optimize(::Gurobi.Model) at grb\_solve.jl:5  
> optimize!(::Gurobi.GurobiMathProgModel) at MPBWrapper.jl:425  
> #solve#116(::Bool, ::Bool, ::Bool, ::Array{Any,1}, ::Function, ::JuMP.Model) at solvers.jl:175  
> macro expansion at model\_callback\_full.jl:1218 [inlined]  
> anonymous at :?  
> include\_string(::String, ::String) at loading.jl:522  
> include\_string(::String, ::String, ::Int64) at eval.jl:30  
> include\_string(::Module, ::String, ::String, ::Int64, ::Vararg{Int64,N} where N) at eval.jl:34  
> (::Atom.##102#107{String,Int64,String})() at eval.jl:82  
> withpath(::Atom.##102#107{String,Int64,String}, ::String) at utils.jl:30  
> withpath(::Function, ::String) at eval.jl:38  
> hideprompt(::Atom.##101#106{String,Int64,String}) at repl.jl:67  
> macro expansion at eval.jl:80 [inlined]  
> (::Atom.##100#105{Dict{String,Any}})() at task.jl:80

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<div class="post-metadata">

**Author:** ![odow](https://sea2.discourse-cdn.com/julialang/user_avatar/discourse.julialang.org/odow/32/28685_2.png) [@odow](https://discourse.julialang.org/u/odow)\
**Post date:** [October 1, 2018, 4:46pm UTC](https://discourse.julialang.org/t/does-anyone-know-how-to-retrieve-the-number-of-generated-cuts-in-the-informational-callback/15370/9 "2018-10-01T16:46:07Z")

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> I see that there is a method definition for “mip\_cutcnt”.

Good spotting! In which case, the function you had above should work (once you add it to MPBWrapper.jl).

> [@CBongiova](#):
>
> function cbgetmipcutcnt(d::GurobiCallbackData)  
> @assert d.state == :MIPSol  
> return cbget\_mip\_cutcnt(d.cbdata, d.where)  
> end

You should be able to call it as `numcuts = Gurobi.cbgetmipcutcnt(cb)`.

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<div class="post-metadata">

**Author:** ![CBongiova](https://sea2.discourse-cdn.com/julialang/user_avatar/discourse.julialang.org/cbongiova/32/4856_2.png) [@CBongiova](https://discourse.julialang.org/u/CBongiova)\
**Post date:** [October 2, 2018, 9:44am UTC](https://discourse.julialang.org/t/does-anyone-know-how-to-retrieve-the-number-of-generated-cuts-in-the-informational-callback/15370/10 "2018-10-02T09:44:40Z")

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@odow Thanks for your help!  
The code is working. I opened an issue on the Gurobi.jl page with the code I want to add as you suggested 🙂  
[https://github.com/JuliaOpt/Gurobi.jl/issues/160](https://github.com/JuliaOpt/Gurobi.jl/issues/160)