# \#ipopt

**URL:** https://discourse.julialang.org/tag/ipopt/897.md

[Latest](https://discourse.julialang.org/latest.md) · [Categories](https://discourse.julialang.org/categories.md) · [Tags](https://discourse.julialang.org/tags.md)

---

## [Ipopt has trouble with \`Vector{AffExpr} in MOI.Zeros\`](https://discourse.julialang.org/t/ipopt-has-trouble-with-vector-affexpr-in-moi-zeros/138395)

<div class="topic-metadata">

**Author:** [@bernardofpc](https://discourse.julialang.org/u/bernardofpc)\
**Replies:** 10\
**Last updated:** [August 8, 2026, 8:30am UTC](https://discourse.julialang.org/t/ipopt-has-trouble-with-vector-affexpr-in-moi-zeros/138395 "2026-08-08T08:30:50Z")

</div>

I have a JuMP model where solving with HiGHS and Ipopt results in different objective\_values. A JuMP Model ├ solver: Ipopt ├ objective\_sense: MIN\_SENSE │ └ objective\_function\_type: AffExpr ├ num\_variables: 54 ├ num\_cons…

---

## [90% of Ipopt run time is spent in Hessian/constraints evaluation, very little time in linear solver. Is it normal?](https://discourse.julialang.org/t/90-of-ipopt-run-time-is-spent-in-hessian-constraints-evaluation-very-little-time-in-linear-solver-is-it-normal/136708)

<div class="topic-metadata">

**Author:** [@Ceserik](https://discourse.julialang.org/u/Ceserik)\
**Replies:** 11\
**Last updated:** [April 18, 2026, 7:55am UTC](https://discourse.julialang.org/t/90-of-ipopt-run-time-is-spent-in-hessian-constraints-evaluation-very-little-time-in-linear-solver-is-it-normal/136708 "2026-04-18T07:55:51Z")

</div>

Hello, I have been trying to improve my solve time for nonlinear optimal control problem , it is a tool for solving minimum lap time for a race car GitHub - ceserik/SLapSim.jl: Scalable laptime simulator · GitHub. I am…

---

## [Get Lagrange multipliers from Ipopt with Optimization.jl](https://discourse.julialang.org/t/get-lagrange-multipliers-from-ipopt-with-optimization-jl/134074)

<div class="topic-metadata">

**Author:** [@nico](https://discourse.julialang.org/u/nico)\
**Replies:** 1\
**Last updated:** [November 24, 2025, 1:41pm UTC](https://discourse.julialang.org/t/get-lagrange-multipliers-from-ipopt-with-optimization-jl/134074 "2025-11-24T13:41:53Z")

</div>

Hi everyone! I’m working with the Julia packages Optimization.jl and Ipopt.jl to solve a nonlinear programming (NLP) problem. I’m successfully solving the problem, but I need to extract the final Lagrange multipliers (…

---

## [Min max Ipopt opti : error in step computation](https://discourse.julialang.org/t/min-max-ipopt-opti-error-in-step-computation/132429)

<div class="topic-metadata">

**Author:** [@baroqueuse](https://discourse.julialang.org/u/baroqueuse)\
**Replies:** 6\
**Last updated:** [September 22, 2025, 12:40pm UTC](https://discourse.julialang.org/t/min-max-ipopt-opti-error-in-step-computation/132429 "2025-09-22T12:40:06Z")

</div>

Hello everybody. I want to solve a min max problem with Ipopt solver. I used the trick described in JuMP documentation (section tips and tricks). I managed to write my problem but the optimization do not work. I hade t…

---

## [Quickest way to build solution sensitivity information from Ipopt (sIpopt)](https://discourse.julialang.org/t/quickest-way-to-build-solution-sensitivity-information-from-ipopt-sipopt/132144)

<div class="topic-metadata">

**Author:** [@chensunn](https://discourse.julialang.org/u/chensunn)\
**Replies:** 1\
**Last updated:** [September 6, 2025, 7:31pm UTC](https://discourse.julialang.org/t/quickest-way-to-build-solution-sensitivity-information-from-ipopt-sipopt/132144 "2025-09-06T19:31:36Z")

</div>

I’m trying to use JuMP and Ipopt to get sensitivity information of the optimal solution to certain parameters. This is functionality that already exists in sIpopt (doi:10.1007/s12532-012-0043-2), but I don’t believe that…

---

## [IPOPT Watchdog Iterations Tracking](https://discourse.julialang.org/t/ipopt-watchdog-iterations-tracking/129159)

<div class="topic-metadata">

**Author:** [@leespen1](https://discourse.julialang.org/u/leespen1)\
**Replies:** 2\
**Last updated:** [May 19, 2025, 10:17pm UTC](https://discourse.julialang.org/t/ipopt-watchdog-iterations-tracking/129159 "2025-05-19T22:17:28Z")

</div>

In IPOPT.jl, is there any way to obtain the diagnostic information or alpha\_pr? The callback function example given in repo is: function my\_callback( alg\_mod::Cint, iter\_count::Cint, obj\_value::Float64, inf…

---

## [Specifying the Hessian for some (but not all) user-defined operators](https://discourse.julialang.org/t/specifying-the-hessian-for-some-but-not-all-user-defined-operators/128741)

<div class="topic-metadata">

**Author:** [@franckgaga](https://discourse.julialang.org/u/franckgaga)\
**Replies:** 2\
**Last updated:** [May 6, 2025, 11:41am UTC](https://discourse.julialang.org/t/specifying-the-hessian-for-some-but-not-all-user-defined-operators/128741 "2025-05-06T11:41:35Z")

</div>

In ModelPredictiveControl.jl, I build the nonlinear optimization problem of NonLinMPC using multiple user-defined operators in JuMP.jl. One operator is for the objective function, the other operators appear in the nonlin…

---

## [Can Ipopt provide a dual bound?](https://discourse.julialang.org/t/can-ipopt-provide-a-dual-bound/128354)

<div class="topic-metadata">

**Author:** [@WalterMadelim](https://discourse.julialang.org/u/WalterMadelim)\
**Replies:** 2\
**Last updated:** [April 24, 2025, 6:57am UTC](https://discourse.julialang.org/t/can-ipopt-provide-a-dual-bound/128354 "2025-04-24T06:57:46Z")

</div>

Continuing the discussion from Getting duals for nonlinear programming problem: As an extension, I asked ChatGPT this problem. Can anyone tell me where is its idea from? Does its reply make sense?

---

## [Warm starting Ipopt with higher discretization points](https://discourse.julialang.org/t/warm-starting-ipopt-with-higher-discretization-points/127974)

<div class="topic-metadata">

**Author:** [@Dhormir](https://discourse.julialang.org/u/Dhormir)\
**Replies:** 8\
**Last updated:** [April 23, 2025, 9:43pm UTC](https://discourse.julialang.org/t/warm-starting-ipopt-with-higher-discretization-points/127974 "2025-04-23T21:43:01Z")

</div>

Hello, I’m fairly new to Julia and using Ipopt as a solver, and currently I’m facing the following problem. I’m solving an Optimal control problem with a discretization size of N. Then what I want to do is grab the prov…

---

## [Ipopt does NOT memorize a best solution found so far](https://discourse.julialang.org/t/ipopt-does-not-memorize-a-best-solution-found-so-far/127244)

<div class="topic-metadata">

**Author:** [@WalterMadelim](https://discourse.julialang.org/u/WalterMadelim)\
**Replies:** 7\
**Last updated:** [April 23, 2025, 7:24am UTC](https://discourse.julialang.org/t/ipopt-does-not-memorize-a-best-solution-found-so-far/127244 "2025-04-23T07:24:14Z")

</div>

The title is expounded through optimizing this function function g(x) return sin(7 \* x) + 1.2 \* cos(4.7 \* x) + 1.3 \* x end which can be visualized via, e.g. using CairoMakie f = Figure(); Axis(f\[1, 1\]); xs = LinRange(…

---

## [Error with Ipopt.jl and ipopt.out file](https://discourse.julialang.org/t/error-with-ipopt-jl-and-ipopt-out-file/127596)

<div class="topic-metadata">

**Author:** [@nico](https://discourse.julialang.org/u/nico)\
**Replies:** 3\
**Last updated:** [April 2, 2025, 7:16pm UTC](https://discourse.julialang.org/t/error-with-ipopt-jl-and-ipopt-out-file/127596 "2025-04-02T19:16:29Z")

</div>

Hi, I have a simple test code, that used to work and now gives an error. When I run the code the first time, Ipopt manages to solve the toy problem and print the output to a .txt file. The second time I run the code, …

---

## [Solving large scale NLP problem on HPC cluster](https://discourse.julialang.org/t/solving-large-scale-nlp-problem-on-hpc-cluster/127134)

<div class="topic-metadata">

**Author:** [@J-Holger](https://discourse.julialang.org/u/J-Holger)\
**Replies:** 5\
**Last updated:** [March 25, 2025, 8:50am UTC](https://discourse.julialang.org/t/solving-large-scale-nlp-problem-on-hpc-cluster/127134 "2025-03-25T08:50:42Z")

</div>

Hello, I’m trying to solve a maximization problem for maximizing profit in river hydroelectricity power production. The problem is non-linear and non-convex. I’m using the solution from a simplified, linear and convex, …

---

## [Ipopt's "local" optimum can be very substandard](https://discourse.julialang.org/t/ipopts-local-optimum-can-be-very-substandard/127217)

<div class="topic-metadata">

**Author:** [@WalterMadelim](https://discourse.julialang.org/u/WalterMadelim)\
**Replies:** 8\
**Last updated:** [March 23, 2025, 12:15am UTC](https://discourse.julialang.org/t/ipopts-local-optimum-can-be-very-substandard/127217 "2025-03-23T00:15:15Z")

</div>

Continuing the discussion from The solution deteriorates if the domain of decisions is improperly set when using Ipopt: The title is expounded with 3 examples, where the result of the first one is completely unaccepta…

---

## [The solution deteriorates if the domain of decisions is improperly set when using Ipopt](https://discourse.julialang.org/t/the-solution-deteriorates-if-the-domain-of-decisions-is-improperly-set-when-using-ipopt/126743)

<div class="topic-metadata">

**Author:** [@WalterMadelim](https://discourse.julialang.org/u/WalterMadelim)\
**Replies:** 4\
**Last updated:** [March 15, 2025, 5:36am UTC](https://discourse.julialang.org/t/the-solution-deteriorates-if-the-domain-of-decisions-is-improperly-set-when-using-ipopt/126743 "2025-03-15T05:36:06Z")

</div>

We expound the title through the following Convex Minimization Problem. function convex\_f(x) return x \* log(x) end # ⚠️ This convex function is NOT defined at 0 function f\_gradient(x) return log(x) + 1 end import JuM…

---

## [Restrictions when adding a binary variable - Local Infeasibility (Ipopt, Juniper)](https://discourse.julialang.org/t/restrictions-when-adding-a-binary-variable-local-infeasibility-ipopt-juniper/121870)

<div class="topic-metadata">

**Author:** [@fynnhoffmann54](https://discourse.julialang.org/u/fynnhoffmann54)\
**Replies:** 15\
**Last updated:** [January 23, 2025, 8:27am UTC](https://discourse.julialang.org/t/restrictions-when-adding-a-binary-variable-local-infeasibility-ipopt-juniper/121870 "2025-01-23T08:27:21Z")

</div>

Hello, I am trying to model a nonlinear optimization problem involving binary variables and continuous variables. Specifically, I cannot understand why a binary variable “z\_sys\_to\_HP(s)” makes the model unusable. My mo…

---

## [Limiting step size in optimization variable between optimization steps of nonlinear constrained optimization problem](https://discourse.julialang.org/t/limiting-step-size-in-optimization-variable-between-optimization-steps-of-nonlinear-constrained-optimization-problem/117732)

<div class="topic-metadata">

**Author:** [@psuskin](https://discourse.julialang.org/u/psuskin)\
**Replies:** 4\
**Last updated:** [August 20, 2024, 2:19pm UTC](https://discourse.julialang.org/t/limiting-step-size-in-optimization-variable-between-optimization-steps-of-nonlinear-constrained-optimization-problem/117732 "2024-08-20T14:19:11Z")

</div>

Hi, I am trying to limit the step size of an optimization variable between optimization steps for a nonlinear constrained optimization problem using JuMP and Ipopt. In case this goal or the motivation behind it is uncl…

---

## [How to speed up ipopt with HSL ma86 using parallel processing](https://discourse.julialang.org/t/how-to-speed-up-ipopt-with-hsl-ma86-using-parallel-processing/117567)

<div class="topic-metadata">

**Author:** [@Chi\_Jan](https://discourse.julialang.org/u/Chi_Jan)\
**Replies:** 7\
**Last updated:** [July 30, 2024, 2:42am UTC](https://discourse.julialang.org/t/how-to-speed-up-ipopt-with-hsl-ma86-using-parallel-processing/117567 "2024-07-30T02:42:18Z")

</div>

Hi community, I was previously using IPOPT with MUMPS (which is the default) to solve my problem, but the performance was a bit slow. I obtained an academic license for HSL and successfully downloaded and ran the code as…

---

## [Struggle at large scale problem of nlp using ipopt](https://discourse.julialang.org/t/struggle-at-large-scale-problem-of-nlp-using-ipopt/116240)

<div class="topic-metadata">

**Author:** [@Chi\_Jan](https://discourse.julialang.org/u/Chi_Jan)\
**Replies:** 10\
**Last updated:** [June 26, 2024, 10:47pm UTC](https://discourse.julialang.org/t/struggle-at-large-scale-problem-of-nlp-using-ipopt/116240 "2024-06-26T22:47:57Z")

</div>

hi there, I have a non-linear problem where the decision variable is a matrix of dimensions m \* n \* k. The constraints may also be somewhat complex. When I set m to a small subset of the dataset, e.g., 10, the program se…

---

## [User defined gradient in JuMP with Ipopt: gradient with user data](https://discourse.julialang.org/t/user-defined-gradient-in-jump-with-ipopt-gradient-with-user-data/116236)

<div class="topic-metadata">

**Author:** [@vict\_riag](https://discourse.julialang.org/u/vict_riag)\
**Replies:** 3\
**Last updated:** [June 26, 2024, 10:15pm UTC](https://discourse.julialang.org/t/user-defined-gradient-in-jump-with-ipopt-gradient-with-user-data/116236 "2024-06-26T22:15:56Z")

</div>

Hello, I have been trying to register a gradient in JuMP that includes user data. I think the issue is with how I have formulated the gradient and fed it into JuMP, but I am not sure how to use the @expression or @param…

---

## [Nonlinear Least Squares Millions of Allocations](https://discourse.julialang.org/t/nonlinear-least-squares-millions-of-allocations/115583)

<div class="topic-metadata">

**Author:** [@nicrummel](https://discourse.julialang.org/u/nicrummel)\
**Replies:** 9\
**Last updated:** [June 15, 2024, 1:43am UTC](https://discourse.julialang.org/t/nonlinear-least-squares-millions-of-allocations/115583 "2024-06-15T01:43:44Z")

</div>

Overview An algorithm I am working on requires solving many largish nonlinear least squares problems. The number of allocations is exploding. My nonlinear function are efficient when passed Arrays of Float64 and generate…

---

## [Trajectory Optimization using Pseudospectral collocation](https://discourse.julialang.org/t/trajectory-optimization-using-pseudospectral-collocation/114017)

<div class="topic-metadata">

**Author:** [@DTdev](https://discourse.julialang.org/u/DTdev)\
**Replies:** 10\
**Last updated:** [May 30, 2024, 3:46pm UTC](https://discourse.julialang.org/t/trajectory-optimization-using-pseudospectral-collocation/114017 "2024-05-30T15:46:13Z")

</div>

Hi everyone! I am currently trying to solve a simple trajectory optimization problem using pseudospectral collocation or orthogonal collocation. I have written a simple UAV simulation using JuMP.jl with a moving obstac…

---

## [How to get HSL up and running with Ipopt](https://discourse.julialang.org/t/how-to-get-hsl-up-and-running-with-ipopt/114138)

<div class="topic-metadata">

**Author:** [@heiwie](https://discourse.julialang.org/u/heiwie)\
**Replies:** 6\
**Last updated:** [May 11, 2024, 4:12pm UTC](https://discourse.julialang.org/t/how-to-get-hsl-up-and-running-with-ipopt/114138 "2024-05-11T16:12:50Z")

</div>

Hello, I have recently received an academic license for HSL, and so I wish to try this linear solver out for Ipopt in order to see if there is an increase in performance of my model. Based on this source: GitHub - jump-…

---

## [Nonlinear Optimization with Many Constraints + Autodifferentiation: Which Julia Solution?](https://discourse.julialang.org/t/nonlinear-optimization-with-many-constraints-autodifferentiation-which-julia-solution/110678)

<div class="topic-metadata">

**Author:** [@SebKrantz](https://discourse.julialang.org/u/SebKrantz)\
**Replies:** 23\
**Last updated:** [March 15, 2024, 6:42pm UTC](https://discourse.julialang.org/t/nonlinear-optimization-with-many-constraints-autodifferentiation-which-julia-solution/110678 "2024-03-15T18:42:18Z")

</div>

I’m trying to rewrite a Matlab Package in Julia which solves a high-dimensional non-linear optimal transport problem in order to maximize economic welfare as predicted by a linked quantiative trade model. In particular, …

---

## [Use of integer variables Juniper Error (MI-NLP)](https://discourse.julialang.org/t/use-of-integer-variables-juniper-error-mi-nlp/111454)

<div class="topic-metadata">

**Author:** [@Erlendgh](https://discourse.julialang.org/u/Erlendgh)\
**Replies:** 2\
**Last updated:** [March 14, 2024, 10:40am UTC](https://discourse.julialang.org/t/use-of-integer-variables-juniper-error-mi-nlp/111454 "2024-03-14T10:40:16Z")

</div>

Hi, I’m trying to solve an optimization problem (MI-NLP) where I want certain variables to be integer values. I have tried to get a bunch of different packages/solver to work and landed on Juniper. My code works fine wh…

---

## [Long NLP evaluation time in Ipopt](https://discourse.julialang.org/t/long-nlp-evaluation-time-in-ipopt/109436)

<div class="topic-metadata">

**Author:** [@tso-martin](https://discourse.julialang.org/u/tso-martin)\
**Replies:** 6\
**Last updated:** [February 14, 2024, 6:56am UTC](https://discourse.julialang.org/t/long-nlp-evaluation-time-in-ipopt/109436 "2024-02-14T06:56:32Z")

</div>

Dear all, I encounter long evaluation times and slow convergence in an AC security constraint optimal power flow (SCOPF) optimization. The problem is modelled with PowerModels and JuMP. The NLP evaluation time is higher…

---

## [Converting non-linear optimization with fmincom from Matlab to Julia](https://discourse.julialang.org/t/converting-non-linear-optimization-with-fmincom-from-matlab-to-julia/106536)

<div class="topic-metadata">

**Author:** [@Alfespo97](https://discourse.julialang.org/u/Alfespo97)\
**Replies:** 12\
**Last updated:** [November 23, 2023, 5:23pm UTC](https://discourse.julialang.org/t/converting-non-linear-optimization-with-fmincom-from-matlab-to-julia/106536 "2023-11-23T17:23:11Z")

</div>

Hi, I’m new to Julia language and I’m trying to replicate an optimization function created in Matlab using fmincom in Julia in order to improve the computation time that is quite huge in Matlab. I’ve used the JuMP mode…

---

## [How to set a Non-linear function with double summatory](https://discourse.julialang.org/t/how-to-set-a-non-linear-function-with-double-summatory/105542)

<div class="topic-metadata">

**Author:** [@PatrickeTownsend](https://discourse.julialang.org/u/PatrickeTownsend)\
**Replies:** 4\
**Last updated:** [October 29, 2023, 9:18pm UTC](https://discourse.julialang.org/t/how-to-set-a-non-linear-function-with-double-summatory/105542 "2023-10-29T21:18:54Z")

</div>

Hello Again! I’m trying to solve this optimization problem: But i’m not really sure about how to write down that objective function, I tried doing this: using JuMP using Ipopt model = Model(Ipopt.Optimizer) set\_att…

---

## [Is there a Symbolics.jl interface to Ipopt (or similar)?](https://discourse.julialang.org/t/is-there-a-symbolics-jl-interface-to-ipopt-or-similar/100149)

<div class="topic-metadata">

**Author:** [@votroto](https://discourse.julialang.org/u/votroto)\
**Replies:** 17\
**Last updated:** [June 14, 2023, 10:49pm UTC](https://discourse.julialang.org/t/is-there-a-symbolics-jl-interface-to-ipopt-or-similar/100149 "2023-06-14T22:49:05Z")

</div>

Hello, is there an interface to Ipopt which can accept Symbolics functions? There is NLPModelsIpopt, which accepts NLPModels. Going via ADNLPModels seems unnecessary as Symbolics can already provide all the hessians, ja…

---

## [Callback function in IPOP for catching inner iterations](https://discourse.julialang.org/t/callback-function-in-ipop-for-catching-inner-iterations/98246)

<div class="topic-metadata">

**Author:** [@Annaquest](https://discourse.julialang.org/u/Annaquest)\
**Replies:** 1\
**Last updated:** [May 4, 2023, 9:02pm UTC](https://discourse.julialang.org/t/callback-function-in-ipop-for-catching-inner-iterations/98246 "2023-05-04T21:02:03Z")

</div>

Hi, I am currently using a callback function to get the number of inner iterations. Firstly, I have this: set\_optimizer\_attributes(model, “mu\_target” =\> μ, “mu\_init” =\> μ); Where μ is updated outside of IPOPT ( I hav…

---

## [Nested Sum in NLObjective -](https://discourse.julialang.org/t/nested-sum-in-nlobjective/96890)

<div class="topic-metadata">

**Author:** [@Gregoryo](https://discourse.julialang.org/u/Gregoryo)\
**Replies:** 2\
**Last updated:** [March 31, 2023, 3:06pm UTC](https://discourse.julialang.org/t/nested-sum-in-nlobjective/96890 "2023-03-31T15:06:00Z")

</div>

Hi, I am totally new to both Julia and Optimization and I am trying to define a non linear objective that requires nested sums. I found some examples that I am trying to replicate, but I get an error. This is how I set m…

[Next page](https://discourse.julialang.org/tag/ipopt/897.md?match_all_tags=true&page=1&tags%5B%5D=ipopt)