# Announcements **URL:** https://discuss.ampl.com/c/announcements/39.md [Latest](https://discuss.ampl.com/latest.md) · [Categories](https://discuss.ampl.com/categories.md) · [Tags](https://discuss.ampl.com/tags.md) --- ## [About the Announcements category](https://discuss.ampl.com/t/about-the-announcements-category/147)
**Author:** [@fdabrandao](https://discuss.ampl.com/u/fdabrandao)\ **Replies:** 0\ **Last updated:** [November 28, 2022, 12:27pm UTC](https://discuss.ampl.com/t/about-the-announcements-category/147 "2022-11-28T12:27:07Z")
This category for AMPL related announcements such as new features, new APIs, new solver driver releases an so on. --- ## [FINAL CALL for Optimization Modeling & Deployment Sessions at 2026 INFORMS Annual Meeting](https://discuss.ampl.com/t/final-call-for-optimization-modeling-deployment-sessions-at-2026-informs-annual-meeting/2234)
**Author:** [@4er](https://discuss.ampl.com/u/4er)\ **Replies:** 0\ **Last updated:** [April 26, 2026, 4:22pm UTC](https://discuss.ampl.com/t/final-call-for-optimization-modeling-deployment-sessions-at-2026-informs-annual-meeting/2234 "2026-04-26T16:22:35Z")
There’s still time to join our Community Sessions in the area of “Optimization Modeling & Deployment Software” at the 2026 INFORMS Annual Meeting, to be held November 1-4, 2026 in San Francisco (meetings.informs.org/word… --- ## [LAST CALL for Optimization Modeling & Deployment speakers @ 2025 INFORMS Annual Meeting](https://discuss.ampl.com/t/last-call-for-optimization-modeling-deployment-speakers-2025-informs-annual-meeting/2129)
**Author:** [@4er](https://discuss.ampl.com/u/4er)\ **Replies:** 0\ **Last updated:** [May 6, 2025, 5:41pm UTC](https://discuss.ampl.com/t/last-call-for-optimization-modeling-deployment-speakers-2025-informs-annual-meeting/2129 "2025-05-06T17:41:39Z")
Presentations are invited at the INFORMS Annual Meeting — Atlanta, October 26-29 — on all aspects of modeling software and tools for optimization, including representation of mathematical optimization problems, interface… --- ## [Call for Presentations: OPTIMIZATION MODELING AND DEPLOYMENT SOFTWARE at INFORMS Annual Meeting 2025](https://discuss.ampl.com/t/call-for-presentations-optimization-modeling-and-deployment-software-at-informs-annual-meeting-2025/2117)
**Author:** [@4er](https://discuss.ampl.com/u/4er)\ **Replies:** 0\ **Last updated:** [April 16, 2025, 5:43pm UTC](https://discuss.ampl.com/t/call-for-presentations-optimization-modeling-and-deployment-software-at-informs-annual-meeting-2025/2117 "2025-04-16T17:43:41Z")
Presentations are invited for sessions in the area of “Optimization Modeling & Deployment Software” at the 2025 INFORMS Annual Meeting, to be held October 26-29, 2025 in Atlanta, Georgia. Submissions are welcome on all … --- ## [AMPL INFORMS Webinar "Teaching & Learning Optimization" Wednesday, December 13](https://discuss.ampl.com/t/ampl-informs-webinar-teaching-learning-optimization-wednesday-december-13/849)
**Author:** [@4er](https://discuss.ampl.com/u/4er)\ **Replies:** 0\ **Last updated:** [December 9, 2023, 5:11pm UTC](https://discuss.ampl.com/t/ampl-informs-webinar-teaching-learning-optimization-wednesday-december-13/849 "2023-12-09T17:11:59Z")
Are you involved in teaching or learning large-scale optimization? We invite you to check out next week’s INFORMS Sponsored Webinar presented by AMPL: Date: Wednesday, December 13, 2023 Time: 12:00-1:00 EST (UTC-5) S… --- ## [AMPL Modeling Tips #7: Logistic Regression with Exponential Cones](https://discuss.ampl.com/t/ampl-modeling-tips-7-logistic-regression-with-exponential-cones/657)
**Author:** [@fdabrandao](https://discuss.ampl.com/u/fdabrandao)\ **Replies:** 0\ **Last updated:** [July 27, 2023, 12:08pm UTC](https://discuss.ampl.com/t/ampl-modeling-tips-7-logistic-regression-with-exponential-cones/657 "2023-07-27T12:08:44Z")
Given a sequence of training examples x\_i \\in \\mathbf{R}^m, each labelled with its class y\_i\\in \\{0,1\\} and we seek to find the weights \\theta \\in \\mathbf{R}^m which maximize the function: \\sum\_{i:y\_i=1} \\log(S(\\theta^… --- ## [Last Call: Optimization Modeling session @ fall INFORMS](https://discuss.ampl.com/t/last-call-optimization-modeling-session-fall-informs/522)
**Author:** [@4er](https://discuss.ampl.com/u/4er)\ **Replies:** 0\ **Last updated:** [April 28, 2023, 4:59pm UTC](https://discuss.ampl.com/t/last-call-optimization-modeling-session-fall-informs/522 "2023-04-28T16:59:33Z")
LAST CALL! Optimization Modeling Software session INFORMS Annual Meeting, October 15-18, 2023 Deadline for speaker names: Tuesday, May 2 Deadline for abstracts: Tuesday, May 16 To participate in this session, you ne… --- ## [AMPL Modeling Tips #6: Robust Linear Programming with Ellipsoidal Uncertainty](https://discuss.ampl.com/t/ampl-modeling-tips-6-robust-linear-programming-with-ellipsoidal-uncertainty/487)
**Author:** [@fdabrandao](https://discuss.ampl.com/u/fdabrandao)\ **Replies:** 0\ **Last updated:** [April 10, 2023, 4:34pm UTC](https://discuss.ampl.com/t/ampl-modeling-tips-6-robust-linear-programming-with-ellipsoidal-uncertainty/487 "2023-04-10T16:34:31Z")
Sometimes values are not known exactly In the diet problem we want to find a diet that satisfies certain nutricial requiments while also minimizing the total cost. What if the costs were not know exactly? One simple … --- ## [AMPL Modeling Tips #5: Non-contiguous variable domains](https://discuss.ampl.com/t/ampl-modeling-tips-5-non-contiguous-variable-domains/387)
**Author:** [@fdabrandao](https://discuss.ampl.com/u/fdabrandao)\ **Replies:** 0\ **Last updated:** [February 20, 2023, 6:02pm UTC](https://discuss.ampl.com/t/ampl-modeling-tips-5-non-contiguous-variable-domains/387 "2023-02-20T18:02:05Z")
Sometimes variable values are restricted to non-contiguous sets. Finite domain: var Buy {FOOD} in {0, 10, 30, 45, 55}; Finite domains as unions of integer sets: var Buy {FOOD} in 0..4 union 9..13 union 17..20; A … --- ## [AMPL Modeling Tips #4: If-Then](https://discuss.ampl.com/t/ampl-modeling-tips-4-if-then/354)
**Author:** [@fdabrandao](https://discuss.ampl.com/u/fdabrandao)\ **Replies:** 0\ **Last updated:** [February 2, 2023, 12:32pm UTC](https://discuss.ampl.com/t/ampl-modeling-tips-4-if-then/354 "2023-02-02T12:32:31Z")
Assume that production of a specific item i costs u\_i per unit, but there is an additional fixed charge of w\_i if we produce item i at all. For instance, w\_i could be the cost of setting up a production plant, initia… --- ## [AMPL Modeling Tips #3: Alldifferent](https://discuss.ampl.com/t/ampl-modeling-tips-3-alldifferent/305)
**Author:** [@fdabrandao](https://discuss.ampl.com/u/fdabrandao)\ **Replies:** 0\ **Last updated:** [January 10, 2023, 5:35pm UTC](https://discuss.ampl.com/t/ampl-modeling-tips-3-alldifferent/305 "2023-01-10T17:35:23Z")
Consider the N-Queens problem: How can N queens be placed on an NxN chessboard so that no two of them attack each other? \[ Solve it on Google Colab! \] Constraint alldiff enforces a set of integer variables to take d… --- ## [AMPL Modeling Tips #2: Equivalence](https://discuss.ampl.com/t/ampl-modeling-tips-2-equivalence/268)
**Author:** [@fdabrandao](https://discuss.ampl.com/u/fdabrandao)\ **Replies:** 0\ **Last updated:** [December 15, 2022, 1:03pm UTC](https://discuss.ampl.com/t/ampl-modeling-tips-2-equivalence/268 "2022-12-15T13:03:05Z")
“Of two variables x and y, exactly one should be positive”: how to model this constraint? This is a stricter condition that in the previous Tip #1. For the new MP Library-based drivers (e.g., gurobi, highs, cbc, copt, x… --- ## [AMPLXL - Quick Example](https://discuss.ampl.com/t/amplxl-quick-example/317)
**Author:** [@Nicolau\_Santos](https://discuss.ampl.com/u/Nicolau_Santos)\ **Replies:** 0\ **Last updated:** [January 17, 2023, 3:11pm UTC](https://discuss.ampl.com/t/amplxl-quick-example/317 "2023-01-17T15:11:03Z")
There are multiple ways to import data into AMPL. One of them is amplxl , a table handler for spreadsheets in the .xlsx format. In this post we will take a quick look on how to use amplxl in the diet problem, available … --- ## [Prescriptive analytics using R API by Andrés Felipe Insuasty Chamorro](https://discuss.ampl.com/t/prescriptive-analytics-using-r-api-by-andres-felipe-insuasty-chamorro/152)
**Author:** [@AMPLDevTeam](https://discuss.ampl.com/u/AMPLDevTeam)\ **Replies:** 0\ **Last updated:** [November 28, 2022, 2:30pm UTC](https://discuss.ampl.com/t/prescriptive-analytics-using-r-api-by-andres-felipe-insuasty-chamorro/152 "2022-11-28T14:30:09Z")
Please check out this post from Andrés Felipe Insuasty Chamorro where he invites the community of Prescriptive Analytics to try AMPL APIs like R and Python in their optimization work. Linked in his original post is a bl… --- ## [Call for Presentations: SOFTWARE FOR OPTIMIZATION -- IFORS 2023, Santiago, Chile](https://discuss.ampl.com/t/call-for-presentations-software-for-optimization-ifors-2023-santiago-chile/375)
**Author:** [@4er](https://discuss.ampl.com/u/4er)\ **Replies:** 0\ **Last updated:** [February 13, 2023, 5:44pm UTC](https://discuss.ampl.com/t/call-for-presentations-software-for-optimization-ifors-2023-santiago-chile/375 "2023-02-13T17:44:39Z")
I am organizing a cluster of sessions on SOFTWARE FOR OPTIMIZATION at IFORS 2023, the 23rd Conference of the International Federation of Operational Research Societies, to be held in Santiago, Chile, 10-14 July 2023: … --- ## [AMPL and all Solvers are now available as Python Packages](https://discuss.ampl.com/t/ampl-and-all-solvers-are-now-available-as-python-packages/341)
**Author:** [@fdabrandao](https://discuss.ampl.com/u/fdabrandao)\ **Replies:** 0\ **Last updated:** [January 24, 2023, 3:14pm UTC](https://discuss.ampl.com/t/ampl-and-all-solvers-are-now-available-as-python-packages/341 "2023-01-24T15:14:59Z")
AMPL and all Solvers are now available as Python Packages: # Install Python API for AMPL: $ python -m pip install amplpy --upgrade # Install solver modules: $ python -m amplpy.modules install highs gurobi # Activate … --- ## [All-New Xpress 9.0 and CBC 2.10.7 drivers for AMPL](https://discuss.ampl.com/t/all-new-xpress-9-0-and-cbc-2-10-7-drivers-for-ampl/198)
**Author:** [@fdabrandao](https://discuss.ampl.com/u/fdabrandao)\ **Replies:** 0\ **Last updated:** [December 8, 2022, 9:02pm UTC](https://discuss.ampl.com/t/all-new-xpress-9-0-and-cbc-2-10-7-drivers-for-ampl/198 "2022-12-08T21:02:11Z")
We are keeping more solvers up-to-date with the release of two more all-new drivers: Xpress 9.0 and CBC 2.10.7. The new drivers provide extended modeling support through the automatic reformulations and linearizations p… --- ## [AMPL Modeling Tips #1: Disjunctions](https://discuss.ampl.com/t/ampl-modeling-tips-1-disjunctions/166)
**Author:** [@fdabrandao](https://discuss.ampl.com/u/fdabrandao)\ **Replies:** 1\ **Last updated:** [December 2, 2022, 12:22pm UTC](https://discuss.ampl.com/t/ampl-modeling-tips-1-disjunctions/166 "2022-12-02T12:22:47Z")
“Two variables x and y cannot be positive at the same time”: how to model this constraint? For the new MP Library-based drivers (e.g., gurobi, highs, copt), as well as for Constraint Programming solvers (ilogcp, gecode, … --- ## [All-New Gurobi 10 Driver for AMPL](https://discuss.ampl.com/t/all-new-gurobi-10-driver-for-ampl/164)
**Author:** [@fdabrandao](https://discuss.ampl.com/u/fdabrandao)\ **Replies:** 0\ **Last updated:** [November 30, 2022, 4:03pm UTC](https://discuss.ampl.com/t/all-new-gurobi-10-driver-for-ampl/164 "2022-11-30T16:03:08Z")
We have an All-New Gurobi 10 driver for AMPL! You may have seen Gurobi recently announce their Gurobi 10 version, and we are right along with their exciting progress with our updated driver. The Gurobi highlights includ… --- ## [New AMPL Forum on Discourse](https://discuss.ampl.com/t/new-ampl-forum-on-discourse/148)
**Author:** [@fdabrandao](https://discuss.ampl.com/u/fdabrandao)\ **Replies:** 0\ **Last updated:** [November 28, 2022, 12:42pm UTC](https://discuss.ampl.com/t/new-ampl-forum-on-discourse/148 "2022-11-28T12:42:29Z")
We are moving away from our Google Group to Discourse. Some main categories that may be interesting to look at: Announcements: #announcements New to AMPL: #new-to-ampl Support: #support (for general support questions… --- ## [Terms of Service](https://discuss.ampl.com/t/terms-of-service/4)
**Author:** [@system](https://discuss.ampl.com/u/system)\ **Replies:** 0\ **Last updated:** [August 16, 2021, 12:38am UTC](https://discuss.ampl.com/t/terms-of-service/4 "2021-08-16T00:38:14Z")
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