# It seems that MadNLP does not support general NLP problem

**URL:** <https://discourse.julialang.org/t/it-seems-that-madnlp-does-not-support-general-nlp-problem/116864>\
**Category:** Optimization (Mathematical)\
**Tags:** jump, nlp\
**Created:** [July 10, 2024, 10:59am UTC](https://discourse.julialang.org/t/it-seems-that-madnlp-does-not-support-general-nlp-problem/116864 "2024-07-10T10:59:25Z")\
**Posts on this page:** 8\
**Page:** 1

<div class="post-metadata">

**Author:** ![JackaChou](https://sea2.discourse-cdn.com/julialang/user_avatar/discourse.julialang.org/jackachou/32/35269_2.png) [@JackaChou](https://discourse.julialang.org/u/JackaChou)\
**Post date:** [July 10, 2024, 10:59am UTC](https://discourse.julialang.org/t/it-seems-that-madnlp-does-not-support-general-nlp-problem/116864/1 "2024-07-10T10:59:25Z")

</div>

I recently used the solver MadNLP to solve the following NLP problem, but the terminal reported that it didn’t support this problem. Isn’t MadNLP a general NLP solver?

> using MadNLP, JuMP  
> m = Model(() → MadNLP.Optimizer(print\_level=MadNLP.INFO, max\_iter=100))  
> @variable(m, 0 \<= x1 \<= 40, start=23.564546)  
> @variable(m, 0 \<= x2 \<= 40, start=33.235712480000004)  
> @objective(m, Min, x1^0.7 + x2^3)  
> optimize!(m)

ERROR: The solver does not support an objective function of type MathOptInterface.ScalarNonlinearFunction.

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<div class="post-metadata">

**Author:** ![pierre-haessig](https://sea2.discourse-cdn.com/julialang/user_avatar/discourse.julialang.org/pierre-haessig/32/217129_2.png) [@pierre-haessig](https://discourse.julialang.org/u/pierre-haessig)\
**Post date:** [July 10, 2024, 3:19pm UTC](https://discourse.julialang.org/t/it-seems-that-madnlp-does-not-support-general-nlp-problem/116864/2 "2024-07-10T15:19:36Z")

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Hi,  
Could it be the same symptom as [NLP: Attribute ScalarNonlinearFunction is not supported by the model](https://discourse.julialang.org/t/nlp-attribute-scalarnonlinearfunction-is-not-supported-by-the-model/110444), that is that MadNLP doesn’t support the new simplified syntax for nonlinear problem (that your are using) introduced in [JuMP 1.15](https://jump.dev/blog/1.15.0-release/) (Sept 2023).

Have you tried with `NLopbjective` instead?

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<div class="post-metadata">

**Author:** ![JackaChou](https://sea2.discourse-cdn.com/julialang/user_avatar/discourse.julialang.org/jackachou/32/35269_2.png) [@JackaChou](https://discourse.julialang.org/u/JackaChou)\
**Post date:** [July 11, 2024, 12:34am UTC](https://discourse.julialang.org/t/it-seems-that-madnlp-does-not-support-general-nlp-problem/116864/3 "2024-07-11T00:34:47Z")

</div>

Thanks, if I change the syntax to what you have said, it works.

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<div class="post-metadata">

**Author:** ![pierre-haessig](https://sea2.discourse-cdn.com/julialang/user_avatar/discourse.julialang.org/pierre-haessig/32/217129_2.png) [@pierre-haessig](https://discourse.julialang.org/u/pierre-haessig)\
**Post date:** [July 11, 2024, 7:32am UTC](https://discourse.julialang.org/t/it-seems-that-madnlp-does-not-support-general-nlp-problem/116864/4 "2024-07-11T07:32:49Z")

</div>

Great! Just a quick question: MadNLP last release [v0.8.3](https://github.com/MadNLP/MadNLP.jl/releases/tag/v0.8.3) is from May 2024, so 6 months after JuMP 1.15. I didn’t see something about supporting the new nonlinear syntax in the last few release notes. But on the other hand, I didn’t find a corresponding [issue](https://github.com/MadNLP/MadNLP.jl/issues).

If you can confirm that your first example fails on their latest release, perhaps this would make a nice minimal reproducible example for opening a ticket?

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<div class="post-metadata">

**Author:** ![JackaChou](https://sea2.discourse-cdn.com/julialang/user_avatar/discourse.julialang.org/jackachou/32/35269_2.png) [@JackaChou](https://discourse.julialang.org/u/JackaChou)\
**Post date:** [July 11, 2024, 11:30am UTC](https://discourse.julialang.org/t/it-seems-that-madnlp-does-not-support-general-nlp-problem/116864/5 "2024-07-11T11:30:43Z")

</div>

Sorry, I have never report a issue with any code. But this is the latest version of MadNLP.

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<div class="post-metadata">

**Author:** ![pulsipher](https://sea2.discourse-cdn.com/julialang/user_avatar/discourse.julialang.org/pulsipher/32/10461_2.png) [@pulsipher](https://discourse.julialang.org/u/pulsipher)\
**Post date:** [July 11, 2024, 6:06pm UTC](https://discourse.julialang.org/t/it-seems-that-madnlp-does-not-support-general-nlp-problem/116864/6 "2024-07-11T18:06:57Z")

</div>

MadNLP started supporting the new nonlinear interface with `v0.8` via [Add support for MOI.ScalarNonLinearFunction by frapac · Pull Request #280 · MadNLP/MadNLP.jl · GitHub](https://github.com/MadNLP/MadNLP.jl/pull/280) as detailed in their [NEWS.md](https://github.com/MadNLP/MadNLP.jl/blob/master/NEWS.md#v080-mar-7th-2024).

Edit: When I run your code snipped on MadNLP `v0.8.3`, it runs:

```julia-repl
julia> optimize!(m)
This is MadNLP version v0.8.3, running with umfpack

Number of nonzeros in constraint Jacobian............: 0
Number of nonzeros in Lagrangian Hessian.............: 2

Total number of variables............................: 2
                     variables with only lower bounds: 0
                variables with lower and upper bounds: 2
                     variables with only upper bounds: 0
Total number of equality constraints.................: 0
Total number of inequality constraints...............: 0
        inequality constraints with only lower bounds: 0
   inequality constraints with lower and upper bounds: 0
        inequality constraints with only upper bounds: 0

iter objective inf_pr inf_du lg(mu) ||d|| lg(rg) alpha_du alpha_pr ls
   0 3.6721719e+04 0.00e+00 1.00e+02 -1.0 0.00e+00 - 0.00e+00 0.00e+00 0
   1 5.0033422e+03 0.00e+00 2.56e+01 -1.0 1.61e+01 - 2.94e-01 1.00e+00f 1
   2 6.6380159e+02 0.00e+00 6.40e+00 -1.0 8.41e+00 - 9.90e-01 1.00e+00f 1
   3 9.5905322e+01 0.00e+00 1.60e+00 -1.0 1.02e+01 - 1.00e+00 1.00e+00f 1
   4 1.6480842e+01 0.00e+00 3.95e-01 -1.0 8.67e+00 - 1.00e+00 1.00e+00f 1
   5 3.1471060e+00 0.00e+00 9.98e-02 -1.7 3.78e+00 - 1.00e+00 1.00e+00h 1
   6 1.2258080e+00 0.00e+00 7.39e-02 -2.5 1.29e+00 - 1.00e+00 5.02e-01h 1
   7 5.8767314e-01 0.00e+00 3.23e-02 -2.5 4.55e-01 - 4.00e-02 1.00e+00h 1
   8 5.3770297e-01 0.00e+00 2.50e-02 -2.5 2.49e-02 0.0 1.00e+00 1.00e+00h 1
   9 1.8731414e-01 0.00e+00 2.61e-02 -3.8 3.59e+00 - 9.62e-01 5.96e-02h 1
iter objective inf_pr inf_du lg(mu) ||d|| lg(rg) alpha_du alpha_pr ls
  10 3.3918868e-02 0.00e+00 6.45e-03 -3.8 2.67e-01 - 1.00e+00 1.00e+00h 1
  11 1.2221136e-02 0.00e+00 1.47e-03 -3.8 1.27e-01 - 1.00e+00 1.00e+00h 1
  12 1.8567706e-03 0.00e+00 2.28e+00 -5.7 6.99e-02 - 1.00e+00 7.09e-01h 1
  13 1.7955573e-03 0.00e+00 1.63e+01 -5.7 5.11e-02 - 1.00e+00 2.42e-02h 2
  14 3.0429784e-04 0.00e+00 7.65e-01 -5.7 5.53e-02 - 1.00e+00 1.00e+00h 1
  15 1.5877900e-04 0.00e+00 1.10e+00 -5.7 2.67e-02 - 2.06e-01 1.00e+00h 1
  16 1.4912648e-04 0.00e+00 2.36e-02 -5.7 9.42e-03 - 1.00e+00 1.00e+00h 1
  17 1.0328040e-04 0.00e+00 5.47e-02 -5.7 2.47e-03 - 1.00e+00 1.00e+00h 1
  18 1.0740071e-04 0.00e+00 1.31e-03 -5.7 1.39e-04 - 1.00e+00 1.00e+00h 1
  19 1.0715355e-04 0.00e+00 3.71e-06 -5.7 3.32e-07 - 1.00e+00 1.00e+00h 1
iter objective inf_pr inf_du lg(mu) ||d|| lg(rg) alpha_du alpha_pr ls
  20 6.7240224e-05 0.00e+00 2.31e-01 -8.6 9.09e-03 - 1.00e+00 3.50e-01h 2
  21 4.0295309e-05 0.00e+00 1.69e-01 -8.6 9.92e-03 - 1.00e+00 4.29e-01h 2
  22 2.4032511e-05 0.00e+00 2.63e-01 -8.6 8.75e-03 - 1.00e+00 3.95e-01h 2
  23 1.4015849e-05 0.00e+00 3.06e-01 -8.6 7.50e-03 - 1.00e+00 4.04e-01h 2
  24 7.8921046e-06 0.00e+00 4.11e-01 -8.6 6.21e-03 - 1.00e+00 3.92e-01h 2
  25 4.0412565e-06 0.00e+00 5.49e-01 -8.6 5.08e-03 - 1.00e+00 3.76e-01h 2
  26 1.3875878e-06 0.00e+00 3.57e-01 -8.6 4.13e-03 - 1.00e+00 3.13e-01h 2
  27 9.0975161e-07 0.00e+00 2.10e+02 -8.6 3.22e-07 8.6 1.00e+00 4.82e-03h 4
  28 2.2812992e-07 0.00e+00 3.83e+00 -8.6 3.53e-03 - 1.00e+00 1.00e+00h 1
  29 1.4206589e-07 0.00e+00 2.40e+01 -8.6 5.10e-10 10.8 1.00e+00 2.50e-01h 3
iter objective inf_pr inf_du lg(mu) ||d|| lg(rg) alpha_du alpha_pr ls
  30 9.3339023e-08 0.00e+00 4.27e+01 -8.6 7.68e-10 11.2 1.00e+00 6.25e-02h 5
  31 8.5192234e-08 0.00e+00 5.45e+01 -8.6 2.05e-11 12.5 1.00e+00 2.50e-01h 3
  32 5.9706984e-08 0.00e+00 3.51e+01 -8.6 1.11e-03 - 1.00e+00 1.00e+00h 1
  33 3.7459299e-08 0.00e+00 6.25e+01 -8.6 6.15e-11 12.1 1.00e+00 2.50e-01h 3
  34 3.3223540e-08 0.00e+00 8.70e+01 -8.6 3.54e-12 13.4 1.00e+00 5.00e-01h 2
  35 3.1225842e-08 0.00e+00 1.22e+02 -8.6 2.40e-12 13.8 1.00e+00 2.50e-01h 3
  36 3.0490054e-08 0.00e+00 1.57e+02 -8.6 2.60e-12 14.2 1.00e+00 6.25e-02h 5
  37 2.9710386e-08 0.00e+00 3.52e+02 -8.6 1.84e-12 14.7 1.00e+00 6.25e-02h 5
  38 2.9641153e-08 0.00e+00 4.71e+02 -8.6 5.23e-15 16.9 1.00e+00 1.00e+00h 1
  39 2.9586595e-08 0.00e+00 8.78e+02 -8.6 2.79e-15 17.3 1.00e+00 1.00e+00h 1
iter objective inf_pr inf_du lg(mu) ||d|| lg(rg) alpha_du alpha_pr ls
  40 2.7725525e-08 0.00e+00 5.66e+02 -8.6 6.74e-05 - 1.00e+00 1.00e+00h 1
  41 2.7699457e-08 0.00e+00 8.04e+02 -8.6 1.20e-15 17.8 1.00e+00 1.00e+00h 1
  42 NaN 0.00e+00 NaN -8.6 7.52e-16 18.2 1.00e+00 1.00e+00h 1
  43r NaN 0.00e+00 2.51e-01 -8.6 NaN - 1.00e+00 1.00e+00h 1
EXIT: Restoration Failed

```

I suspect you might have have an older package version. You can check via

```julia-repl
julia> ]

(@1.10) pkg> st

```

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<div class="post-metadata">

**Author:** ![pierre-haessig](https://sea2.discourse-cdn.com/julialang/user_avatar/discourse.julialang.org/pierre-haessig/32/217129_2.png) [@pierre-haessig](https://discourse.julialang.org/u/pierre-haessig)\
**Post date:** [July 12, 2024, 8:13am UTC](https://discourse.julialang.org/t/it-seems-that-madnlp-does-not-support-general-nlp-problem/116864/7 "2024-07-12T08:13:31Z")

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> [@pulsipher](#):
>
> MadNLP started supporting the new nonlinear interface with `v0.8` via [Add support for MOI.ScalarNonLinearFunction by frapac · Pull Request #280 · MadNLP/MadNLP.jl · GitHub](https://github.com/MadNLP/MadNLP.jl/pull/280) as detailed in their [NEWS.md](https://github.com/MadNLP/MadNLP.jl/blob/master/NEWS.md#v080-mar-7th-2024).

Thanks for the feedback. I missed that news because 0.8.0 is not listed in the [Release page](https://github.com/MadNLP/MadNLP.jl/releases)

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<div class="post-metadata">

**Author:** ![JackaChou](https://sea2.discourse-cdn.com/julialang/user_avatar/discourse.julialang.org/jackachou/32/35269_2.png) [@JackaChou](https://discourse.julialang.org/u/JackaChou)\
**Post date:** [July 13, 2024, 5:50am UTC](https://discourse.julialang.org/t/it-seems-that-madnlp-does-not-support-general-nlp-problem/116864/8 "2024-07-13T05:50:05Z")

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Thanks for the feedback, it does work. I have used version 0.7.0 due to the compatibility issue.