“Logic” and Constraint Programming Extensions
22 October 2012: The AMPL language has been extended in a variety of ways to take better advantage of constraint programming and mixed-integer programming solvers that deal directly with "logic" in constraints of various kinds. Among these extensions are basic logical operators (and, or, not, exists, forall), conditional operators (if ... then ..., ==>), counting operators (count, atleast, atmost), and operators that facilitate so-called global constraints (alldiff, numberof).Many of the extended operators are recognized by a new AMPL driver for the ILOG Concert Technology C++ interface to the IBM ILOG CP constraint programming optimizer and also the IBM CPLEX mixed-integer programming optimizer. This driver is available to all registered CPLEX for AMPL users including academic and trial license users.
See our new logic extensions page for a syntax and usage summary of all of the extended operators recognized by the new ilogcp driver.
Free Extended Function Library
22 October 2012:
A new, free function library extends AMPL with over 300 functions chosen from the GNU Scientific Library. Included are scientific, statistical, and utility functions of many kinds, and a variety of random number generators.
Once installed and declared, these functions may be applied to any arguments anywhere in an AMPL model or script. When applied to variables in objectives or constraints, they are sent to solvers, which automatically gain access to them. Thus solvers that rely on function evaluations can optimize over expressions that use this library.
Xpress for AMPL Now Available
15 October 2012:
FICO Xpress version 23 for linear, mixed integer, and quadratic programming is now available for purchase with an AMPL interface, directly from AMPL Optimization. A complete, udpated Xpress option listing details settings for access to all of the Xpress solver features. With this addition, we now offer a choice among all of the best MIP optimizers; free trials are available for benchmarking.
AMPL Book Chapters Now Free Online
28 August 2012:
We are pleased to announce that chapters of "AMPL: A Modeling Language for Mathematical Programming" are now freely available for download. This offering became possible through a recent agreement with the book's publisher, who will continue to make hardbound books available for purchase.
Victor is a specialist in mathematical optimization. In 2011 he completed his PhD in Mathematics at Brunel University, UK. His main research interests are stochastic programming and algebraic modeling languages. During and after his PhD Victor worked at OptiRisk Systems on a stochastic programming solver, stochastic extensions to AMPL and an integrated development environment for those extensions. Victor has a first class honors degree in Mathematics from Belarusian State University and many years of software development experience.
Victor Zverovich Joins AMPL Optimization
1 June 2012:
AMPL Optimization is pleased to welcome Victor Zverovich as the newest member of the AMPL team. Victor's skills will play a key role in the development of the next generation of AMPL products.
Gurobi 5.0 for AMPL Now Available
15 May 2012:
Gurobi version 5.0 for linear, mixed integer, and quadratic
programming is now available for purchase with an AMPL interface, both directly through
us and from Gurobi Optimization. This version adds support for quadratic constraints and a variety of performance enhancements. Accounts that are up-to-date on Gurobi for AMPL maintenance and support service can download this major update immediately; other should contact licensing@ampl.com for information.
CPLEX 12.4 for AMPL Now Available
15 May 2012:
IBM ILOG CPLEX version 12.4 for linear, mixed integer, and quadratic
programming is now available for purchase with an AMPL interface, directly from AMPL Optimization. Accounts that are up-to-date on CPLEX for AMPL maintenance and support service can download this significant update immediately; other should contact licensing@ampl.com for information.
CPLEX 12.3 for AMPL Now Available
12 June 2011:
IBM ILOG CPLEX version 12.3 for linear, mixed integer, and quadratic
programming is now available for purchase with an AMPL interface, directly from AMPL Optimization. Those who have purchased earlier versions from us can also arrange to download this update; contact licensing@ampl.com if you need to set up a download account.
Gurobi 4.5 for AMPL Now Available
15 April 2011:
Gurobi version 4.5 for linear, mixed integer, and quadratic
programming is now available for purchase with an AMPL interface, both directly through
us and from Gurobi Optimization. Those who have purchased earlier versions from us can also arrange to download this update; contact licensing@ampl.com if you need to set up a download account.
KNITRO 7.0 for AMPL Now Available
13 October 2010:
KNITRO version 7.0 for nonlinear
optimization in continuous and integer variables is now available for purchase with an AMPL interface, both directly through
us and from Ziena Optimization. Those who have purchased earlier versions from us can also arrange to download this update; contact licensing@ampl.com if you need to set up a download account.
Gurobi may be included as a no-cost item on any academic license order. Those who already have AMPL academic licenses can contact us to arrange to add Gurobi, or can download solver software and academic licenses free of charge from the Gurobi website; see our Gurobi download instructions for details.
CPLEX for AMPL can be obtained without charge through the IBM Academic Initiative; see our CPLEX download instructions for details.
Orders are being taken now, and shipments will begin in June. For a listing of commercial
or academic prices, contact us at info@ampl.com.
We make available the full AMPL/MINOS and AMPL/SNOPT packages in binary form,
and also the solver part of each package for those who have already licensed AMPL.
For a listing of commercial or academic prices, contact us at
info@ampl.com.
KNITRO has been extended to
accept optimization problems that incorporate any of AMPL's complementarity constraints.
Other recent options include Hessian-vector products to speed derivative calculations,
a crossover procedure to make complementarity of the solution more exact,
and a multistart facility that tries multiple random starting points
to search for improved results.
CPLEX allows for indicator constraints
that specify implications directly by means of a ==> operator rather
than indirectly by use of formulation tricks involving zero-one variables. Also
certain problems that have very large collections of equations or inequalities
can benefit by declaring many of them to be lazy constraints or
user cuts. Enhancements for mixed-integer programming that can be requested
from AMPL include taking advantage of infeasible MIP starting solutions, automatic
MIP symmetry-breaking, re-applying presolve after root processing is complete,
and attempting to polish the current solution at the end of the procedure.
Also added is a mechanism for returning a meaningful solution when the problem is
infeasible.
We make available the full AMPL/KNITRO and AMPL/CONOPT packages, and also the
solver part of each package for those who have already licensed AMPL. For a listing
of commercial or academic prices, contact us at
info@ampl.com.
For those who have obtained AMPL from other sources, or are connecting AMPL
to their own solvers, we are selling standalone copies of AMPL. We are also
announcing the availability of AMPL/solver packages, beginning with
AMPL/CONOPT and AMPL/KNITRO
(see above). Additional AMPL/solver packages remain available from our
vendors.
The newly concluded agreement anticipates that current AMPL vendor
agreements will be assigned to AMPL Optimization LLC. Thus initially
AMPL sales and maintenance will continue to be available from existing vendors.
Also under the new agreement, the ampl.com internet domain and
AMPL trademark have been transferred to the new company. Further
developments will continue to be announced on the AMPL home page.
New graphical user interfaces for AMPL are under development. You can
currently download copies of several experimental GUIs, but release dates for
finished products are still to be set.
If you're new to AMPL, you might want to take a look at the quick start
instructions on our downloads page.
Windows users can now get the Student Editions of standard AMPL, CPLEX
8.0, and MINOS 5.5, plus the Kestrel client for internet access to
solvers and a table handler for database access to data, by downloading and
unpacking a single archive file.
(The AMPL Plus Student Edition expired at the end of 2002 as described in the
the January 1, 2003 item above.)
To carry out this update, download the files readme.txt and setup.exe. Then run (double-click)
setup.exe and follow the directions that appear. All of the
files needed to keep running the AMPL Plus 1.6 Student Edition will be
unpacked and written to a folder you can specify,
ready for use. It is OK for this folder to be the same one you have
been using for AMPL Plus, but in this case any files you have changed
since first installing AMPL Plus will be overwritten. More
installation details appear in readme.txt
The availability of AMPL Plus and other AMPL student versions after
2002 is currently under negotiation. Developments will be reported on
the AMPL home page.
The main advantage of AMPL Plus is its
Windows-style graphical user interface. If you do not require this
feature, you can download a
command-line version of the AMPL Student Edition that has no
expiration date.
Kestrel, a new interface to NEOS,
permits you to use many of the NEOS solvers -- currently 9 in all --
through the usual solve command in an AMPL session, with
results returned for display and processing within the AMPL
environment. Currently supported for Windows, Linux, and Sun's SPARC
Solaris, Kestrel is implemented as a single executable file that
takes over the role of the local solver at a traditional AMPL session.
The Try AMPL web interface to the AMPL
Student Edition and solvers also remains available.
7 September 2000: EKA Consulting has added an AMPL
interface to their MOSEK Optimization
Tools. MOSEK includes a simplex method for linear programs and an
interior-point method for linear, convex nonlinear, and convex
quadratically constrained optimization problems.
A new writeup on Relational Database Access
explains the principles and operational details of this feature. You
can try it out now by using the standard (command-line) AMPL Student
Edition in conjunction with a handler for the Open Database
Connectivity (ODBC) standard under Microsoft Windows; see Downloading the standard AMPL database
handler for instructions. This handler supports Microsoft Access
and Excel and any other database software for which an ODBC driver is
installed.
To upgrade the standard AMPL Professional Edition software with
relational database support, contact your AMPL
vendor. As vendors release new AMPL versions that provide this
support, their availability will also be announced on this web site.
(The standard AMPL database features are independent of the database
access facilities in the AMPL Plus
Professional Edition.)
If you purchased an earlier copy of the AMPL book, you can arrange to
download the new AMPL Plus Student Edition 1.6 software. See our book software upgrade instructions for
details.
Solvers for which downloadable versions are referenced include CPLEX,
DONLP2, LOQO, lp_solve, MINOS, and WSAT(OIP).
We link to Barnes
& Noble or Amazon.com,
depending on which seems to be shipping fastest. If you're determined
to get the lowest possible price, you might also want to try the
listings from AddAll or BestBookBuys; try searching on the
book's ISBN, 0534378951.
23 April 1999: Dash
Optimization, Inc. has been added to the list of AMPL
vendors. Dash also sells XPRESS-MP solver software, as well as
consulting, training and customization services.
25 March 1999: Optimal
Solution Technologies, Inc. has joined our lineup of AMPL vendors.
OST also sells IBM OSL solver software and service, and offers
consulting services for data management, modeling and analysis, and
supply chain optimization.
For other AMPL remote execution alternatives, see our description of
AMPL Remote Access via the NEOS Server.
Full-Featured MIP Solvers Available Free for Academic Use
20 September 2010:
The AMPL-enabled versions of two popular mixed-integer optimizers are now available free for teaching and research at degree-granting academic institutions. These are full-featured versions that impose no arbitrary limits on problem size.
Purchase CPLEX for AMPL Directly From Us
15 September 2010:
CPLEX for linear, quadratic, and mixed-integer
programming has joined the lineup of AMPL-enabled solvers available for purchase directly from AMPL Optimization LLC. Version 12.2 is currently shipping. Contact us at info@ampl.com for pricing on single-user, floating, and server licenses. Full-featured trials are also available.
Gurobi 3.0 for AMPL Now Available
15 April 2010:
Gurobi version 3.0 for linear and mixed integer
programming is now available for purchase with an AMPL interface, both directly through
us and from Gurobi Optimization.
Purchase Gurobi for AMPL Directly From Us
21 May 2009:
The new solver Gurobi for linear and mixed-integer
programming will be supported by AMPL. Gurobi binaries incorporating the AMPL interface
will be
available for purchase directly from AMPL Optimization LLC, together with AMPL for new
users, and separately for current users of AMPL with other solvers. We will also offer
free student versions restricted to 500 variables and constraints, and unrestricted
30-day trial licenses.
Purchase AMPL/MINOS and AMPL/SNOPT Directly From Us
7 April 2008:
Two Systems Optimization Laboratory
solvers —
MINOS and
SNOPT — are
now available for purchase with AMPL interfaces directly from AMPL Optimization LLC.
Both are general-purpose solvers for large-scale smooth optimization problems
having linear or nonlinear objectives and constraints. Each
uses specific optimization methods that have varying strengths
for different kinds of problems. Comparisons can be made by submitting AMPL problems
to the NEOS Server or by arranging
through us for short-term trial
licences.
Support for new features in CPLEX 11
1 February 2008:
AMPL's communications with CPLEX have been enhanced to add support for two major
features introduced in the new version 11:
AMPL cplex_options directives have also been added to request or control a
variety of features new to CPLEX 11, including zero-half cuts,
a feasibility-pump heuristic, "dynamic search" as an alternative to traditional
branch-and-cut, alternative node relaxations for solving quadratically constrained
mixed-integer problems, and choice of deterministic and opportunistic modes in
parallel optimization.
For an updated account of all CPLEX options controllable through AMPL, see
the summary in
README.cplex
and the ILOG
AMPL CPLEX System 11.0 User's Guide.
Support for new features in KNITRO 5.1 and CPLEX 10.1
30 November 2006:
AMPL has added support for features introduced in recent versions of
these two solvers. Our INFORMS Pittsburgh
slides show a variety of examples.
AMPL Studio Graphical Interface and AMPL COM Objects Now Available
11 January 2006:
AMPL
Studio is a new AMPL product that offers a graphical user interface to
AMPL and to several solvers, including FortMP, CPLEX and MINOS. It provides for viewing
multiple model, data, and result displays, and for organizing AMPL files into projects
and workspaces. All AMPL commands remain available through command-entry
and console windows. AMPL Studio is available from
OptiRisk Systems, who also offer
a collection of COM
Objects for embedding AMPL into Windows applications.
AMPL Newsgroup Established at
Google.com
8 August 2005:
Post questions, give advice, or search the archives at our newly
established newsgroup. To browse postings, visit our
group home page.
To have postings automatically mailed to you, indicate your
preferences at our group
join-up page or enter your email address in the Google box on the
AMPL home page.
Purchase AMPL/KNITRO and AMPL/CONOPT Directly From Us
19 December 2004, 24 July 2004: The
AMPL/KNITRO and
AMPL/CONOPT nonlinear solvers are now available for
purchase directly from AMPL Optimization LLC. Both are general-purpose solvers
for large-scale problems having nonlinear objectives and/or constraints. Each
uses specific optimization methods that have varying strengths
for different kinds of problems. We can arrange trial licenses for benchmarking.
Purchase AMPL Directly From Us
31 May 2004: AMPL is now available for purchase directly from
AMPL Optimization LLC. For a listing of commercial or academic prices,
contact us at info@ampl.com.
AMPL Optimization LLC Assumes
14 July 2003: Following an agreement recently concluded
with Lucent Technologies, Inc., responsibility for development and support of
the AMPL modeling language and system has been assumed by AMPL Optimization LLC,
a new company formed by the inventors of AMPL. Lucent is the corporate
parent of Bell Laboratories, where Robert Fourer, David Gay, and Brian
Kernighan initiated the AMPL project in 1985.
Responsibilities for AMPL Development and Support
AMPL Plus Student Edition expired at
the end of 2002
1 January 2003: Due to the
expiration of an embedded CPLEX license, copies of AMPL Plus for
Windows that were distributed with the AMPL book expired on January 1,
2003. Current users should download a standard (command-line) student
edition for Windows, following the instructions on the AMPL download page.
AMPL Book 2nd Edition
8 November 2002: A second edition of AMPL: A Modeling Language for Mathematical
Programming is now
available. It contains updated versions of all of the
material in the first edition, plus new chapters on database and
spreadsheet interactions, command scripts, solver communications, and
complementarity problems. All of the new features described at this
web site in mid-2002 or earlier are now covered in the book.
CPLEX 8.0 Student Edition
for AMPL
8 October 2002:
Users of standard (command-line) AMPL can now download an AMPL student edition of the
new version
8.0 of CPLEX. Like
other AMPL student editions, this AMPL/CPLEX is full-featured but
limited to 300 variables and 300 constraints.
Student Edition software
licenses must be updated for 2002
7 December 2001: The Student
Edition of AMPL Plus 1.6 that is
packaged with the AMPL book will not work
after December 2001. To continue using this software, you must
download and install an updated version that will continue to work
through 2002.
AMPL Remote Access
via NEOS and Kestrel
16 July 2001 (updated 12 October 2001): The NEOS
Server accepts AMPL input to over
20 solvers of various kinds, through web, e-mail, and socket-based
interfaces. These services are available free of charge to anyone who
has the requisite Internet connections. They are intended mainly for
testing, prototyping, and instructional purposes where a guaranteed
schedule or volume of computing resources is not essential, but
currently uses for any legitimate purpose are permitted.
MOSEK AMPL Vendor and Solver
Link
16 July 2001: EKA
Consulting ApS, based in Copenhagen, Denmark, now sells AMPL in
addition to their optimization products.
Relational Database Support
15 June 2000: A flexible new table declaration
defines correspondences from AMPL data and results to relational
database tables maintained by other software. New read
table and write table commands use these
correspondences to move information between AMPL and databases.
Communication with external database software is managed by plug-in
"handlers" that can be loaded as needed.
Scrolling Window
Utility for Windows
15 June 2000: Microsoft Windows users who have been
running standard (command-line) AMPL in an "MS-DOS" window can now
switch to sw.exe, a utility that provides a more convenient
scrolling window with facilities for cut-and-paste and font selection.
See Downloading the "Scrolling
Window" utility for instructions.
Experimental AMPL Graphical Interfaces
17 December 1999: Three new experimental GUIs for AMPL
are available free for downloading. They have a common style, but
differ somewhat in details and capabilities. Tcl/Tk and Java versions
are available as source code, and can be run on many popular Microsoft,
Unix and Linux platforms. A Visual Basic version is available in the
form of an executable including AMPL, the MINOS solver, and the
interface; it requires Windows 95 or later. See the new experimental AMPL GUI page for further
details including download information and screen shots.
AMPL Plus version 1.6
17 December 1999: A new version of the AMPL Plus
graphical user interface for AMPL, CPLEX and MINOS is now available.
Contact ILOG, Inc. for further
information on purchases or upgrades.
AMPL Plus Student Edition version 1.6
17 December 1999: Beginning in early 2000, the AMPL book is to be shipped with updated software on
CD. Components will include a student edition of the AMPL Plus version 1.6 graphical user
interface for Microsoft Windows, restricted to 300 variables and 300
constraints plus objectives but otherwise complete except for certain
advanced database access features, plus the CPLEX 6.5.3 and MINOS 5.5
solvers. For more detailed information, consult the readme file that comes with the new book
software.
MProbe 3.0
6 October 1999: A new version of the MProbe
Nonlinear Function Analyzer for AMPL models features offers numerous
new plotting options, sampling inside any convex enclosure (for
improved accuracy of conclusions), and identification of redundant
constraints and bounds. A student/demo
edition of the new version, bundled with the AMPL Student Edition software, is
available for downloading.
AMPL Software Download Page
5 September 1999: We've collected in one place the
instructions for downloading many versions of AMPL and solvers that are
available at no charge. These versions are restricted to problems of
limited size -- in most cases, to 300 variables and 300 constraints and
objectives -- but are full-featured in other respects. They can be
used to update the AMPL Student Edition software that comes with the AMPL book, or to set up a demonstration
version for small-scale evaluation and testing.
Next-day
Shipping for the AMPL Book
1
September 1999: AMPL: A Modeling Language for Mathematical
Programming is now
shipping within 24 hours most days when ordered via our Optimization Bookstore.
Expanded Lineup of AMPL Vendors
11 August 1999: Unicom
Consultants is the latest addition to the list of AMPL vendors.
Unicom also sells FortMP solver software, several specialized
optimization packages, and consulting services in dtabase design, web
publishing, and optimization.
Try AMPL!
4 August 1998: A simplified interface to the AMPL Student Edition lets you experiment
with AMPL on test problems up to 300 variables and 300 constraints +
objectives. Request any example from the AMPL
book, or use your own model and data files. Specify AMPL commands
for setting options, solving, and displaying results; choose among 8
solvers for linear, nonlinear, and integer programming and complementarity problems. Then push the
"Send" button to solve on our computer. Your most recent
input and cumulative results are returned on one web page, so that it's
easy to make changes and solve again.
Enhanced Solver Interface Features
4 August 1998: New status
features automatically start simplex solvers from the most
recent optimal basis, examine or modify basis status, and test for
infeasibility, unboundedness, and other solver results. New suffix features expand the range of
specialized information that can be exchanged with solvers. For
example, CPLEX uses user-defined
suffixes to specify individual priorities for integer variables,
and solver-defined suffixes to
provide diagnostic information for infeasible problems and to report
sensitivity ranges.
Complementarity Problems
3 April 1998: A new constraint operator,
complements, permits linear and nonlinear complementarity
problems to be expressed directly and naturally as AMPL constraints.
Both standard and mixed complementarity conditions are supported. The
first solver to take advantage of these new forms is Dirkse and
Ferris's PATH; users
can download the the AMPL/PATH
interface routines from netlib.
MProbe 2.0
28 February 1998: A new version of the MProbe Nonlinear Function Analyzer for AMPL models features a faster 32-bit implementation, recognition of quadratic forms, and tools for assessing constraint region convexity, constraint "effectiveness" and likelihood of a global optimum. A student/demo version bundled with the AMPL Student Edition remains available for downloading.
AMPL Remote Access
1 February 1998: To simplify the work of comparing and testing solvers, we have undertaken a project to make AMPL and solver resources available over the Internet, in collaboration with the NEOS Server project of the Argonne/Northwestern Optimization Technology Center. AMPL users can interact with the NEOS server by requesting runs of both AMPL and solvers at a remote site, or by using a local AMPL session to send optimization problems to remote solvers. Five solvers -- DONLP2, LANCELOT, LOQO, MINOS, and SNOPT -- are initially available.
AMPL in Action: Toxic Waste Disposal
15 November 1997: In this addition to the AMPL in Action case studies section, a pharmaceutical and chemicals company seeks to improve its scheduling of a special toxic waste furnace. An AMPL mixed-integer program determines a solution that increases throughput by 20% while more evenly distributing filter load and reducing slag burnoff.
AMPL in Action: "Balanced Assignment"
16 October 1997: A company divides its employees at meetings and training sessions into groups "as diverse as possible" with respect to several characteristics. The resulting problem differs in key ways from the textbook "assignment problem" and other familiar applications of optimization. AMPL's power and flexibility are advantageous in trying out many alternative models in for quickly modifying models to accommodate new requirements.
NEOS Server for LOQO Supports AMPL Input
14 October 1997: AMPL models, data and command files for linear and quadratic programs can now be submitted to the NEOS Server for solution by LOQO. Submissions can be made (and results returned) either through a web page or by e-mail. AMPL support is planned for a number of other solvers currently supported by NEOS.
AMPL Interface for XPRESS-MP
12 September 1997: The XPRESS-MP solvers for linear programming (simplex or interior) and integer programming are now available with an AMPL interface. Contact Dash Associates for further information.
Enhanced LOQO 3.07 with Built-In AMPL Interface
16 August 1997: The newly released version 3.07 of Vanderbei's LOQO solver finds locally optimal points for general (smooth) nonlinear functions (as well as global optimums for the usual linear and convex cases). You can download demo executables with a built-in AMPL interface for most popular Unix workstations and for PCs running Linux. Just install the executable file loqo in your search path and set option solver loqo to access the new version from AMPL when you issue a solve command. Since LOQO's interior-point algorithm requires Hessian (2nd derivative) information, AMPL is the currently the only modeling language that supports it for general nonlinear optimization.
Shared Libraries for User-Defined Functions
21 July 1997: AMPL now provides a more convenient way to make your own functions available to models and solvers, through the use of shared libraries (also known as dynamic-link libraries, or DLLs). A new ampl/solvers/funclink directory in netlib provides an introduction, together with system-dependent examples and makefiles.
AMPL in Action
3 June 1997: This new section presents five summaries of practical AMPL applications:
- Meat Product Blend Optimization
- High-School Teacher Scheduling
- Location of Distribution Centers
- Airline Fleet Assignment
- Strategic Planning of Train Crews
Expanded Support for Nonlinear Solvers
25 April 1997: AMPL's public routines for linking to nonlinear solvers have been extended in two significant respects:- Automatic recognition of partial separability. A nonlinear
function can be recognized as a sum of terms that each depend on only a
few variables (possibly after a linear change of variables).
- Computation of Hessians. Elements of the matrix of 2nd derivatives can be computed in a range of forms. Partial separability can be exploited to speed the computations.
AMPL/LANCELOT
25 April 1997: AMPL has become the first modeling language to offer a full-featured link to the highly-regarded nonlinear solver LANCELOT. The AMPL interface automatically provides LANCELOT with the partially separable structure of nonlinear objectives and constraints, as well as Hessian information if requested.LANCELOT is one of several solvers that you can now download at minimal cost for use with AMPL. For further information, see our updated listing of Solvers that Work with AMPL.
1997 Meetings and Tutorials
29 January 1997: Our list of conferences and tutorials of interest to optimization users has been updated and extended for 1997 (and on into 1998). Details of conference presentations on AMPL features and applications will be added as they become known.
New AMPL Student Edition Software for Windows
22 December 1996: Beginning late 1996, the AMPL book is being shipped with completely updated software. Components include a student edition of the AMPL Plus graphical user interface for Microsoft Windows, and Windows versions of standard (command-line) AMPL, MINOS 5.5, and CPLEX 4.0.
MProbe: A Nonlinear Function Analyzer for AMPL Models
22 December 1996: We have begun a section on optimization problem analysis tools that work with AMPL. The first entry is MProbe, which provides information on the convexity or concavity (or more generally, the shape) of nonlinear objective and constraint functions. This information is often useful in choosing a solver or solution strategy.
Proposed New AMPL Features
1 November 1996: This new section of the AMPL Web site will present descriptions of new features planned for inclusion in future versions of AMPL. Our first installment includes prospective AMPL extensions for stochastic programming, constraint logic programming, and a more general & powerful solver interface.
AMPL Training Seminar
1 November 1996: A session for beginning to intermediate AMPL users has been scheduled for January 20-21, 1996 in Reno, Nevada.
Software for Optimization: A Buyer's Guide
14 October 1996: Part 2 of this article by AMPL co-developer Robert Fourer, reprinted from the Fall 1996 issue of the INFORMS Computer Science Technical Section Newsletter,has been added.
AMPL at the INFORMS Atlanta Meeting
29 September 1996: Uses of AMPL are described in a tutorial and three invited talks at this fall's INFORMS meeting, November 3-6. The AMPL meetings page provides details, including links to abstracts.
Books on Optimization
15 August 1996: A variety of titles, most of them recommended in the Linear Programming FAQ. Most are available (on special order) from Amazon.com Books; simply click any title or titles to order.
Testing the Solver Return Message
13 August 1996: A new built-in symbolic parameter can be tested, using the AMPL string functions, to distinguish optimality, infeasibility, and other conditions at the most recent solver run. This feature is particularly useful in AMPL scripts that loop over one or more solve commands.
Software for Optimization: A Buyer's Guide
6 June 1996: Part 1 of an article by AMPL co-developer Robert Fourer, reprinted from the Spring 1996 issue of the INFORMS Computer Science Technical Section Newsletter.
New Writeups for String-Handling and Other Features
24 April 1996: Descriptions of new functions, operators and conventions that help you work with set members and other character-string data in AMPL. Topics include: string functions and operators, string expressions in AMPL commands, number-to-string conversions, string-to-number conversions, character-code conversions, and display formats for strings. Examples include automatic generation of sets like {"WEEK1","WEEK2","WEEK3"} and of filename sequences like diet1.out, diet2.out, diet3.out . . .Other newly documented features include read for importing unformatted data; delete, purge and redeclare for removing or redefining declarations of model components; and xref for listing all components dependent on a given component.
Downloadable Student Editions for Unix
14 March 1996: Links to updated versions of the AMPL Student Edition for popular Unix workstations from Hewlett-Packard, IBM, Silicon Graphics and Sun, and for LINUX running on PCs. (Solvers still must be supplied independently, for now.)The latest versions of the DOS Student Edition (which accompanies the AMPL book) also remain available for downloading.
Meetings page
5 March 1996: A listing of conferences, symposia and meetings having a substantial focus on aspects of large-scale optimization. Presentations and tutorials of special relevance to AMPL are highlighted.
Advanced AMPL Tutorial
1 March 1996: in conjunction with the spring meeting of INFORMS, Sunday, May 5, 7:00-10:00 pm, Georgetown East Room, Washington Hilton Hotel: Topics to be covered include new features (looping and if-then-else statements, implementing iterative schemes), application development (single-stepping, expanding constraints, system integration), upcoming enhancements, and more.
Optimization on the Web
17 February 1996: Expanded listings of on-line information sources.
New feature writeups in hypertext
6 February 1996: Descriptions of features added after the AMPL book's publication have been converted to html format.
Guide to exercises
25 January 1996: Instructors may request a guide to the AMPL book's end-of-chapter exercises.
Meetings
15 January 1996: Forthcoming conferences relevant to large-scale optimization are listed, with details of AMPL-related talks and sessions.
CONOPT
10 January 1996: CONOPT, for nonlinear programming problems, joins the list of solvers available for use with AMPL.
Comments or questions?
Write to info@ampl.com or use our comment form.
LAST MODIFIED 22 OCTOBER 2012 BY 4er.