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TROUBLES.!!!
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1991-10-01
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┌──────────────────────────────────────── Bob Obenchain, Ph.D.─────────┐
│ ╥───┐ ╖ ┌─ (tm) │
│ ║ │ ╙╖┌─┘ │
│ ╓─┐ ╓─┐ ╓── ─╥─ ╟─┬─┘ ╙┼╖ ╓─┐ ╖ ┌ ╓─┐ ╥─┐ ╥─┐ ╥ ┌ ┌ ╓─┐ ╥─┐ ╥─┐ │
│ ╙─┐ ║ │ ╟─ ║ ║ └┐ ┌─┘╙╖ ╙─┐ ╟─┤ ╟─┤ ╟┬┘ ╟─ ║ │ │ ╟─┤ ╟┬┘ ╟─ │
│ ╙─┘ ╙─┘ ╨ ╨ ╨ └ ─┘ ╙ ╙─┘ ╜ └ ╜ └ ╜└─ ╨─┘ ╙─┴─┘ ╜ └ ╜└─ ╨─┘ │
└─ 5261 Woodfield Drive North, Carmel, IN 46033, (317) 580-0144 voice ─┘
TROUBLES !!! TROUBLES !!! TROUBLES !!!
Are you are having trouble getting RXridge.EXE to execute properly
on your system?
Here are some common problems that users of RXridge have experienced
as well as some suggestions for their SOLUTION !!!
My screen goes BLACK !!!
========================
At startup, RXridge asks the user to specify whether his/her
monitor supports color and/or graphics. And the "default"
values one gets by simply pressing the ENTER key in response
to these first two prompts are "COLOR"=YES and "CGA or better
GRAPHICS"=YES. A black screen can result from claiming to
have color support when, in reality, one's monitor is actually
monochrome (MGA or HGC.) And RXridge's graphical trace displays
will be, at best, "unreadable" unless your system is at least
"emulating" CGA graphics before RXridge is invoked. It is
essential to give CORRECT responses (for your current hardware
and software configuration) to RXridge's initial color/graphics
prompts!
If your monitor provides only MGA or HGC services, see the file
named SRX_CGA.DOC in the softRX.EXE archive for information
about "emulating" CGA graphics using the SIMCGA40.EXE archive.
My system HANGS...or RXridge HALTS with an OUT-OF-MEMORY message !!!
====================================================================
On its startup screen, RXridge displays the approximate amount of
"memory" still available for dynamic allocation to matrices (after
RXridge is, itself, loaded into memory.) If your system provides
the maximum MS-DOS size of 640 kBytes, there can be as much as
300 kBytes still available after RXridge is loaded. If RXridge
reports that your system has much less than 200 or 300 kBytes of
memory still available after RXridge is loaded, you will NOT be able
to handle "large" regression models. If you system typically has
memory resident software (like, say, SideKick) installed, you should
consider eliminating these systems from memory BEFORE invoking
RXridge.
RXridge is like a puppy-dog who will literally "eat" memory until
he/she is about to explode. In fact, with "unlucky" combinations
of memory needed/requested, RXridge WILL explode! So, watch for
RXridge's reports of "available memory" as execution progresses.
Once memory availability becomes critically low for the regression
model you have specified, you can always terminate RXridge
yourself by choosing a "Q"uit or e"X"it menu option. In these
cases, you will need to reformulate your model using fewer
regressor variables and/or fewer observations.
On the other hand, you can ignore RXridge's warnings about memory
availability IF you are willing to risk the potential for a
mandatory soft/warm reboot via Ctrl/Alt/Del or [if you are really
unlucky] a hard/cold reboot by toggling the Big-Red-Switch !
RXridge ABORTS with a stack-underflow or floating point exception !!!
=====================================================================
RXridge makes MAJOR demands on the data management and numerical
computation capability of your personal computer. For example,
if your system has a numerical mathematics coprocessor (8087,
80287 or 80387) that runs at a slower clock speed than your main
processor (8088, 80286 or 80386), RXridge computations can get
sabotaged. If the rather small numerical examples distributed
with RXridge do not execute fully on your system, some sort of
speed mismatching among system components could be the cause.
RXridge is compiled with Microsoft C 6.00 default settings that
will either detect (and use) your system's numeric math
coprocessor or, when no coprocessor is present, simulate numeric
math with software. You may force RXridge into this software-
math mode, even when your system has a numeric math coprocessor,
by defining an environmental string as follows BEFORE starting
RXridge:
set no87=true
If your system has a numeric math coprocessor that is "slow"
(relative to your main processor), turning off this coprocessor
is likely to make RXridge run even more slowly. But RXridge is
also much less likely to ABORT with error messages in this case!
RXridge HALTS with a notice on Numerical Inaccuracy !!!
=======================================================
RXridge uses some iterative algorithms (in particular, for
Singular Value Decomposition or SVD) that can fail to converge
when your data contains "too many" decimal places. As an
overall "rule-of-thumb," it is probably best to include no more
than 6 significant digits when inputing data to RXridge.
GOOD LUCK !!! ........................................Bob Obenchain