|
| From: | Chen, Jenny |
| Subject: | [Help-glpk] Questions about the GLPK Package |
| Date: | Fri, 15 Jan 2010 02:05:50 +0300 |
Dear GLPK Personnel:
ICF came across the GLPK package via recommendations from
operations research analysts working within the Office of Integrated Analysis
and Forecasting within the Energy Information Administration (EIA). ICF
is helping the EIA conduct a survey of solvers that can serve as cost-effective
alternatives to solver engines such as DASH and CPLEX. Below, I #8217;ve
listed several questions that I have about GLPK. If you can take a moment
to answer them, I would greatly appreciate it. Thank you!
Software Requirements
What are the input/output
capabilities for the solver? Does the solver have the capability for
input/output files of the following formats: (a) delimited text (i.e. csv,
etc); (b) structured text (i.e. xml, etc); (c) spreadsheets (i.e. xls,
xlsx); (d) databases (i.e. Access databases); (e) proprietary
format? Does the solver support other database providers (e.g.
Microsoft SQL Server, Oracle, MySQL, or PostgreSQL)? What database
drivers does the solver support? (e.g. native driver, OLE, ODBC)
Do external programs
become integrated with the solver through: (a) static linkage; (b) dynamic
linkage (i.e. DLL, shared objects, etc); (c) COM, DCOM, OLE; (d) RPC,
network client-server, other or (e) all of the above, depending on the
type of external program (If so, can you go into details?)?
Would the licensed user
have access to the source code so as to alter capabilities of the solver
to meet users #8217; needs? If not, what add-in capabilities are
available to licensed users?
How are upgrades made
available to licensed users? Would the solver provide them to
licensed users for free for 1 year after purchase of a license?
ICF is interested in
learning more about how the solver outputs runtime debug information. For
example, if one of ICF #8217;s programmers writes source code for a new
model, how would he or she output runtime errors and warnings? Does the
solver provide a function to output debug information to a text file,
database, system log, etc, or some combination of multiple output mediums?
What is the cost of a
license per user?
What are the operating
system requirements for the solver? (e.g. edition of Windows
operating system, 32- or 64-bit? RAM required? Disk space required?)
With which programming
language does the solver have an interface? What kind of interfaces
are these? (e.g. interactive, object-oriented, etc)
Calculation Requirements
How many variables and
constraints can the solver accommodate? Can you provide your answer
by type of problem? (e.g. x and y number of variables and constrain
for a linear and quadratic programming problem, respectively)
Size limitations #8211;
what are the size limitations of the model in terms of memory, and
dimensions of arrays?
Compare runs #8211; does
the user interface allow the use of comparing runs
What is the solver #8217;s
graphing capability? How many variables can be graphed against each
other? 2? 3? Can variables be compared against one
another in a table format?
What is the
software #8217;s capability to create a customized template for displaying
results via graphs and defining each variable on the graphs?
Export Capabilities #8211;
what are the solver #8217;s capabilities to export data to be graphed in
another program (e.g. Excel)? To export graphs into other
programs? To what programs can the data and graphs be exported?
Does the user
interface/graphic capability of the software allow the user to look at the
model at an aggregated level, and then in more detail? For instance,
say the final result shows fuel consumption for all residential consumers
in the US. Would the interface/graphic capability show consumption
of a particular type of fuel (e.g. natural gas, wind, or solar) for
a particular state?
How does the solver read
in data or the math programming language? How does it deal with data
that have more than 2 dimensions?
Does the solver have the
capability to solve linear programming, mixed integer programming,
quadratic, and mixed integer quadratic programming problems? What
are some of the solver #8217;s limitations and/or glitches when solving
linear/mixed integer/quadratic/mixed integer quadratic programming
problems?
Can the solver just solve
for individual components of the model, not the entire model, at any given
time?
Can different users use
the optimizing engine to solve for different components of model
simultaneously?
Can you estimate the time
for the optimizing engine to solve a model, based on the size of the
model?
Because the Energy
Information Administration #8217;s (EIA) National Energy Modeling System
(NEMS) is considered public information, EIA must often make the source
code, input files, and optimizing engine available to outside users.
How could the solver be made available through these outside users?
Is there a separate licensing term for them?
Can other solvers be added
to the DLL or other kinds of library in which solver engines are
kept? For instance, the EIA originally used a solver from
KETRON. Later, it decided that the DASH optimizing engine met some
of its other needs. KETRON customized its solver so that it can call
DASH. Does the solver have the capability for this kind of
revision? In what kinds of application programming language can the
DLL or library be embedded?
ICF is currently dealing
with input files that contain large multi-dimensional arrays with few
non-zero entries. How does the solver deal with sparse matrices?
Would this method permit allocation of less memory to large sparse
matrices?
What are the
solver #8217;s presolve and postsolve capabilities so as to make data more
manageable?
What kinds of data
management tools are used in the solver for generating matrices and
reports, optimization control, and solution access? How do they work
with database and spreadsheet applications such as Access and Excel?
How do they work with text files?
Can a user view a log that
reports status of the model run during the optimization process?
Could the status be made available after a certain number of
iterations? If so, how is this done?
Jenny
C. Chen
Associate
ICF
International
9300
Lee Highway
Fairfax,
VA 22031
Phone:
703-218-2714
Fax:
703-934-3915
|
Dear GLPK Personnel: ICF came across the GLPK package via recommendations from
operations research analysts working within the Office of Integrated Analysis
and Forecasting within the Energy Information Administration (EIA). ICF
is helping the EIA conduct a survey of solvers that can serve as cost-effective
alternatives to solver engines such as DASH and CPLEX. Below, I’ve
listed several questions that I have about GLPK. If you can take a moment
to answer them, I would greatly appreciate it. Thank you! Software Requirements
Calculation Requirements
Jenny
C. Chen Associate ICF
International 9300
Lee Highway Fairfax,
VA 22031 Phone:
703-218-2714 Fax:
703-934-3915 |
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