Introduction to the PDP Simulation Environment - Computational Explorations in Cognitive Neuroscience - page 423

statistics associated with a given grain of processing are
automatically logged when that process is logged, un-
less specifically told not to log (using the log_stat
toggle on the statistic object).
A particularly important type of statistic is the Mon-
itorStat , which records (monitors) state information
from the network for display in the log. These monitor
stats can be configured from within the NetView dis-
play, by clicking on a set of units to monitor, and then
creating a new monitor stat from the Monitor Val-
ues menu.

A.11.2 GraphLog

The variables being plotted in the GraphLog are repre-
sented by buttons along the lower left hand side of the
window. The display state of the variable is indicated by
the little “led” in the button. To toggle the display state
on or off, just click with the left mouse button. One of
the variables must serve as the X (horizontal) axis of the
graph. This is indicated by the presence of the X to the
right of the button. To select a different variable as the
X axis, use the middle mouse button.
Some variables will share a common Y (vertical) axis
scale. The Y axes are color coded, with the color of the
line to the right of the variable button indicating which
axis the variable is using. Note that the first variable
(from the top) which has this color Y axis must be dis-
played, or else all the other variables will create their
own Y axis.
Various display attributes of the variables can be
edited by clicking with the right mouse button on the
variable button. This will bring up an edit dialog.
This should not be necessary for any of the provided
projects, and further documentation is available in the
full PDP++ manual.
Finally, the user can click with the left mouse button
on any line in the graph to view the precise numerical
value at a given point. Pressing the Init button in the
upper right hand side of the window will remove any
numerical values being displayed. Further, this button
will generally fix any display problems that might occur
with the graph. The Update button can also be used
if for some reason the graph does not display the most
current information.

A.11 Logs

There are three main types of log displays, the TextLog,
the GraphLog, and the GridLog (the NetLog just dis-
plays in the network window). Each displays the same
information, but using a different output format. The
specific content displayed in the log is determined en-
tirely by the process that is updating the log — the job
of the log is to then take this information and display it
in a specified manner.
All of the logs have VCR-like buttons at the top that
perform full rewind, fast rewind, slow rewind, slow
forward, fast forward, and full forward. These but-
tons move the (small) window of currently-displayed
information across the (larger) set of total information
recorded by the log. The logs will not automatically up-
date unless they are at the end of this total set of data (to
allow you to view prior information even as new data is
being recorded).
If for some reason the log does not appear to be up-
dating when the simulation is being run, press the full
forward button to make sure it is at the end of the data
(where the latest information is).

A.11.3 GridLog

The grid log displays information as grids of colored
blocks, which is very useful for monitoring network
state over time (i.e., from a MonitorStat). The display
is organized like a text log in columns of variables with
each row representing a new iteration of the updating
process. The layout and display properties (i.e., whether
to display text or as a colored block) of the items within
the log can be manipulated interactively by moving and
reshaping the header labels at the top of each column,
or by clicking with the right mouse button on the label

A.11.1 TextLog

The text log simply displays the information as columns
of numbers. Each row corresponds to a different itera-
tion of processing of the updating process object. This
type of log is most useful for summary levels of pro-
cessing, such as training or batch level information.