From: emclean@sfsuvax1.sfsu.edu (Emmett McLean)
Subject: AGSS (A Graphical Statistical System) <> written in APL2
Organization: San Francisco State University
Distribution: NA
Date: Tue, 24 Nov 1992 04:38:03 GMT

This a promotional post I'm making it on behalf a some
fellow APL programmers I know through APLBUG group in
the Bay Area.  For those of you who have never heard of AGSS 
this is a brief account of what it has to offer.  At the
bottom of this post is the name and address of Lewis Peters,
who would like to teach a course in using AGSS if there is
sufficient interest. Feel free to contact him. (What follows
comes from me and is not affiliated with SFSU in any way.)

A Graphical Statistical System (AGSS)

System Overview
---------------
AGSS is an IBM interactive system for 2 and 3 dimensional scientific 
engineering graphics, applied statistics and data analysis.  It runs
under APL2 on a 386 (or higher) PS/2 on a RISC System/6000, or on a VM
host system. (See requirements below.)  It is an easy to use, menu
driven system with on line helps for each entry field and extensive hard
copy documentation.  It is widely used within the Research, Development, 
and Marketing operations of IBM.

2/D Scientific Engineering Graphics
------------------------------------
X,Y plots are easily produced using default options.  Easy access is
provided for the control of all plot characteristics.  These include line
types, symbol types and size, axis labels, plot headings, tic marks,
axis scales and grid characteristics.  Further, the colors of all these
elements can be separately controlled.  Plots can be annotated and
legends easily created.  Over 30 fonts are available as is the ability
to produce super and subscripts.  Hence, publication quality as well as
working graphics are readily produced.  

3/D Scientific Engineering Graphics
----------------------------------- 
The system contains a full range of 3/D plots.  They include surface
plots, contour plots, surface plots combined with projected contour
plots, trajectory plots, scatter plots, and parametric Y,Z plots.   
Complete controls exist for all plot characteristics.

Curve Fitting
-------------
Very powerful screens (menus) exist for applying both linear and
nonlinear least squares to the fitting of curves to data.  For the
linear case a number of commonly used options are provided as well as
the capability of fitting a linear combination of any set of user
specified functions.  A wide range of confidence, tolerance, and
prediction intervals can be generated.  Weighted and robust options
exist.  Residuals can easily be plotted and their distribution
analyzed.  Finally, other linear approaches including smoothing splines
and LOWESS smoothing are available.

The non-linear screen will fit any user specified function of any number
of parameters.  Optionally, upper and/or lower constraints can be placed
on the estimated coefficients.  All the features mentioned in the
connection with the linear case are available.

Surface Fitting
---------------
Linear least squares can be applied to the fitting of surfaces to 3/D 
data.  Bivariate polynomials are explicitly provided but a linear
combination of any user provided functions can be fit.  Coefficient
confidence intervals and residual analyses are available.

Descriptive Statistics and Exploratory Data Analysis
----------------------------------------------------
AGSS provides the following capability: bar charts, pie charts,
skyscraper plots, scatter plot point identification, symmetry plots,
quantile-quantile plots, histograms, empirical CDF's, empirical
densities, percentile plots, box plots, bivarite histograms, and
bivariate empirical densities.

Reliability Analysis and Distribution Fitting
---------------------------------------------
This set of functions is used to fit univariate distributions to data,
provide graphical comparisons of the empirical and fitted
distributions, estimate the parameters of the distributions, and produce
goodness of fit statistics.  Any of 18 distributions may be specified.
For the five distributions commonly used in reliability analysis;
exponential, extreme value, lognormal, normal and Weibull; the system
accepts both censored and interval data.

Plots and tables for the following functions of the fitted distribution
are available: density, CDF, survivor, hazard, cumulative hazard,
reliable life, average hazard rate, and interval failure rate.  In most
cases, pointwise confidence bounds are provided.

Accelerated Life Testing
------------------------
Four screens are provided for simulating and fitting constant stress and
step stress accelerated life test models.  Tests of model hypotheses,
residual analyses and survival analysis (for prediction purposes) are
provided.

Regression Analysis
-------------------
An ordinary least squares screen includes all the common model building
algorithms (stepwise, all possibles subsets, best subset of a given
size, etc). It also includes extensive residual analysis and diagnostic
capabilities as well as detailed analyses of stepwise procedures.  There
is a heavy emphasis on graphical output.  Other screens implement
non-linear, robust, lifetime, and ridge regression.

Design of Experiments
---------------------
This component provides very extensive capabilities for designing and
analyzing 2 level complete or fractional factorial experiments.
Additionally, there are options for blocking, replications within blocks,
center points, and randomization.  The analysis phase includes
probability plots, residual analyses, interaction plots and the analysis
of means.

Quality Control
---------------
The quality control component consists of five screens for the design
and implemention of Shewhart and cusum control charts and the analysis
of means.  The design screens enable you to design control charts having
specified statistical properties in terms of average run length or
operating characteristics.  Each of the control chart screens plots the
control chart, and provides a table of summary statistics.  The
Analysis of Means screen provides the ability to plot Analysis of Means
control charts for any number of factors.

Time Series Analysis
--------------------
There are eighteen screens for the analysis of time series data, the
construction of time series models, and the use of these models for
forecasting.  There is a complete implemention of Box Jenkins univariate
techniques including automatic ARMA model selection and transfer
function models.  Spectral estimates can be generated both through
periodogram smoothing and through the fitting of ARMA models.  Other
capabilites include acf, pacf, and ccf estimation, and Holt Winters
forecasting.

Work Management Utilities
-------------------------
AGSS has a set of catalog screens that enable you to review, execute,
edit and document your screen responses, APL variables, and APL
functions.  It has a file management system that allows you to store and
retrieve these objects efficiently.  In addition it has a diary
facility, which when turned on, will keep a record of all screen
executions.  Thus the system has extensive utilities for the effective
and efficient management of work units. 

Generating Hard Copy Output
---------------------------
PostScript files of graphics output can be generated on both the PS/2
and RS/6000.  Under VM and GDDM, a wide variety of graphics output files
are available.

Relationship to APL
-------------------
Minimal familiarity with APL is required.  Specifically, the user should
understand the basic concepts of an APL variable, an APL array and an
APL function.  More experienced APL users can exploit the power of the
language but this is not necessary to make effective use of the system.
AGSS is synergistic with APL in that the screens entries can be APL
expressions and , in that, the AGSS screens can be used as high level
building blocks within the user's own APL functions.  This gives the
system a unique extendibility.

AGSS Requirements
-----------------
PS/2: 386 (or higher) with coprocessor, 4MB memory, 15MB hard disk, VGA
Display, DOS 3.3 or higher, APL2/PC(Release 1.02).
RS/6000: 15MB hard disk, AIX 3.1 (or higher), APL2/6000.
VM: APL2 1.3 GDDM Release 4 or higher, 4MB Virtual Machine, 20 3380
cylinders, GDDM Terminal with APL keyboard.

Ordering AGSS
-------------
AGSS is an IBM "As-Is" product.  It can be ordered through your local
IBM Branch Office or directly from IBM Research.  (To find out the
location of your local branch office call 800-426-3333.)
Ask for: A Graphical Statistical System (AGSS)
(Listed under SWAPPLIC on the HONE System.  The branch office must
request order forms from ASISCODE at RHQVM21.)  To order directly from
IBM Research send a check made out to "IBM Corporation" to Peter Welch,
IBM Research Center, PO Box 704, Yorktown Heights, NY 10598.  If you
have a problem ordering AGSS or would like more information, call Peter
Welch at 914-784-7560 or Alvin Blum at 914-784-7563.

AGSS Prices: PS/2, $250; RS/6000 $5000; VM, $2500. AGSS is offered with
a 30 day trial period.  

Ordering APL2
-------------
APL2 for the RS/6000 and VM are IBM Program Products and are ordered
through your local IMB Branch Office. To order APL2/PC, call
800-426-2468 and order Part No. 6242936.

Introductory Course
-------------------
Peter Lewis's address and numbers:
:nick.LEWISP                                    :notebook.INET
               :name.Peter A.W. Lewis
               :phone.408:646-2283
               :addr.Department of Operations Research;
                     Naval Postgraduate School;
                     Montery, CA  93943
               :CSADDR.1526P%NAVPGS.bitnet@cunyvm.cuny.edu

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