The CDFwalk program allows direct access to related variable data values.
The data values of up to 27 variables may be displayed at once (the CDF can
have more variables but only 27 may be viewed at any one time).  The data
value for each variable at a given record/index location within the CDF
conceptual view is displayed.  The user can "walk" from one record/index
location to another sequentially (in any "direction") or a particular
record/index location can be "jumped" to directly.  Variable values may
also be used to directly "jump" to a record/index location.

The user interface to CDFwalk is contained on a single screen which is
divided into several fixed windows and pop-up windows.  The Action Menu
controls the execution of the program.  This menu allows you to "walk"
through a CDF, select a new CDF through which to "walk", browse online
help, or exit the program.  This menu may be displayed at any time by
entering Ctrl-F.  Use the up and down arrow keys to highlight a choice in
the Action Menu and then enter a carriage return to execute that function.
Two very important windows are the Keypad Definition and Message windows.
They contain information on keypad functionality and program status/error
messages.

When CDFwalk is executed (and a CDF and/or directory is not entered on the
command line), you must first specify the CDF through which you wish to
"walk".  If you enter a full disk/directory specification (without a CDF
name), all of the CDFs in the specified directory will appear in a separate
pop-up window.  Use the up and down arrow keys to choose a CDF and then
enter a carriage return to "walk" through that CDF.

After the input CDF is selected, the Record/index window appears.  The size
of this window depends on the dimensionality of the input CDF. Vertically
the window will contain one row for the record number and one row for each
dimension of the CDF.  Horizontally, each line of the window contains three
fields.  The first field contains a variable name, the second field
contains a data value for the variable, and the third field contains a
record number or dimension index.

The variable selected for the record number line will be one that only
varies from record to record (not varying along any of the dimensions).  If
more than one variable of that type exists in the CDF, a pop-up window will
be displayed containing the list of variables.  Select one of the variables
keeping in mind that you will have an opportunity to use it for positioning
by value to a desired record.

The variable selected for each dimension line will be one that only varies
along the corresponding dimension (and does not vary from record to
record).  Again, if more than one variable of that type exists in the CDF,
a pop-up window will be displayed to allow you to select the variable to
use for that dimension.  Keep in mind that you will be able to use it to
position by value to a desired index along that dimension.

After the Record/index window has been specified (which may occur
automatically), the Variable Values window will be displayed.  It contains
up to 27 variable names and the associated data values for the record/index
shown in the Record/index window.

Initially the cursor will be positioned at the data value field of the
record number line in the Record/index window.  You may now begin to "walk"
through the CDF by using the right arrow to increment and the left arrow to
decrement the record number.  Each time a new record number is specified,
the data for each variable is updated in both the Record/index and Variable
Values windows.  If the CDF contains many records, you may want to quickly
advance to a desired record.  You may do this by entering the i key (the
cursor must be on the data value field).  CDFwalk enters an input mode and
prompts for the value to which you wish to advance.  If the exact value is
not in the CDF for the variable, the record number is changed to correspond
to the closest possible value.  Another method of advancing to a desired
value is by entering Ctrl-P.  This will cause a pop-up window containing
all of the values for the variable to be displayed.  You may select the
value desired as you would with any other pop-up window, and CDFwalk will
automatically position the record number to the corresponding value.

After positioning to a desired record (and the CDF is multi-dimensional)
you may now wish to "walk" through the dimension index.  This is done by
entering the up and down arrow keys to position the cursor to the desired
dimension line.  "Walking" through dimensions is done in the same way as
"walking" through the record numbers.

You may also wish to "walk" through the CDF by using the actual record
number or dimension index rather than data values.  This is done by
entering a carriage return which causes the cursor to advance to the next
field (i.e., from the data value field to the record number/index field).
Entering Ctrl-H causes the cursor to move back to the previous field.
"Walking" through the CDF using the record number/index fields is the same
as using the data value fields but with a few exceptions.  First, no Ctrl-P
option is available with these fields.  Also, when in input mode, you may
input either an absolute record number/index to which to move or you may
enter a relative offset for the record number/index.  Prefixing the value
with a +/- will increment/decrement the record number/index by that amount.

If the CDF contains more than 27 variables and a particular variable is not
currently displayed in the Variable Values window, an option is provied to
scroll new variables into that window.  This is done by entering a v key.
A small pop-up window is displayed in which you may use the up and down
arrow keys to scroll in or scroll out variables.  If the CDF contains a
very large number of variables, entering a u or d key will display a new
set of 27 variables (moving up or down through the variables in the CDF).
When the desired set of variables is displayed, enter a carriage return to
continue "walking" through the CDF.

When you are finished "walking" through the CDF, enter Ctrl-F to display
the Action Menu.  You may input a new CDF, resume "walking" through the
current CDF, read online help, or exit the program.
