Larry Snyder
The software
described
below was mainly written by me. Some of it was commissioned by
companies, some was developed for research purposes, and some was
written for class projects.
If you'd like information about any of the software listed below, send
me e-mail.
All
downloads
are provided as-is, with no guarantee as to performance or
compatibility. I'm happy to answer simple questions about
the software but I do not provide technical support beyond the Read Me
files included with some of the programs. That said, I have found
the software to work well and believe it to meet the
performance levels I describe below.
Please
Note:
Sorry, but I do not distribute my source code.
Quick Links:
The BaseStockSim software allows users to simulate multi-stage
inventory systems with reliable or unreliable stages. Despite its name, BaseStockSim can
accommodate several types of inventory policies, including base-stock, (R,Q), and (s,S) policies,
as well as a modified (R,Q) policy in which the value of Q is chosen dynamically based on the
values of the state variables. For base-stock policies, base-stock levels are set by the user
explicitly but may also be interpreted using the "committed service time" notion of so-called
guaranteed-service models (see, e.g., Simpson 1958, Kimball 1988, Graves and Willems 2000, 2003).
After running the simulation,
you can view an "instant replay" to examine the inventory and backorder
levels at each stage and watch the system evolve over time. BaseStockSim also has a feature
for performing batch runs in order to test many values of the parameters in sequence.
Download
version 2.4 from the download page.
This
program
implements the Clarke-Wright savings algorithm and various improvement
heuristics for the classical Vehicle Routing Problem.
The screen shot
below
shows the solution reporting screen:
Download the
software from the download page.
| Central Limit Theorem Demo |
This
program
demonstrates the Central Limit Theorem. I wrote it for an
undergraduate
statistics class I taught while at Northwestern.
Download
the
software from the download page.
| IRIS (Integrated Route Information
System) |
I wrote
IRIS
for a major world-wide distributor of perishable goods, in a project
undertaken by myself and my dissertation advisor, Mark Daskin, and
coordinated by the Transportation
Center at Northwestern University. It is a Windows-based
program that plans daily vehicle routes for trucks delivering goods
across the U.S.
and Canada, within customer-specified time windows. Users
input
the customer orders for the day and IRIS plans efficient routes for
trucks
leaving a central depot. Solutions are evaluated based on multiple
criteria, and the user may assign weights to the criteria to
emphasize some more than others. Furthermore, the program
generates multiple solutions as well as alternate solutions
that answer what-if? scenarios
like adding additional vehicles, dropping customers from the order
list,
and so on.
The program
uses
state-of-the-art heuristics to solve the problem, and it presents an
intuitive,
attractive front end to the user. The solver runs quickly and is
intended
to be run several times per day to re-compute the routing strategy as
orders are received by the company's sales staff. Results are
presented in map and text form, and multiple solutions
may be evaluated visually side-by-side using value path diagrams.
The following
screen
shot illustrates IRIS's data input and set-up screens:
The following
two
screen shots show IRIS's solution reporting screens:
A sample
version
of this software will be available for download soon. The sample
version will provide full functionality, but only on a sample data set.
Cryptogrammer
is a Macintosh-based program that allows you to solve cryptograms (word
puzzles) in a graphical environment. You can solve built-in
puzzles or enter your own from newspapers or magazines.
Cryptogrammer has various help
screens that give you breakdowns of frequencies of letters in the
puzzle,
hints when you're stuck, and more. It's a Macintosh-based program
that
I wrote while I was in college.
Cryptogrammer
is
shareware, and you can download it from these sites and others:
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