file: mlabfiles.txt                            date: June 13, 2012

This is information for running MLAB under an MSWindows
operating system. You may want to print this text and keep
it for reference.  Some details differ for Mac OSX and for
Linux, but this information is still valuable for those
systems.

A Quick Example of using MLAB:
------------------------------

When you run MLAB, a "console" window is put on the screen,
and a smaller "start-up menu" window is displayed in which
you must make a selection.

Actually, the very first time you run MLAB, the MLAB console
window will be displayed and you will be asked for a
"user-name". This user-name is kept just for display
purposes; it will subsequently be typed-out in the MLAB
console window before the start-up menu is presented.

And later on, starting on the second day after installation,
until you "register" MLAB, when you run MLAB you will be
asked for an "authorization key-value" that you obtain from
Civilized Software.  When you obtain the authorization
key-value and enter it, you will never be asked for it
again.

Until you obtain your authorization key-value, you should
enter "0". After responding, the MLAB start-up menu window
will be displayed.

(You get the authorization key-value from Civilized Software
by sending-in the "MLAB identifier value" which is typed-out
in the MLAB console window when MLAB starts, and requesting
that the authorization key-value be sent back.  You may send
email to csi@civilized.com.)

One choice in the MLAB start-up menu window is to run
various examples.  Another choice is to go to "top-level",
which means that the startup menu window is removed from the
screen, and a "*" prompt symbol is displayed in the MLAB
console window; this prompt means that MLAB is 'waiting' for
you to enter an MLAB command.  [The first time or two you
run MLAB, you should not go directly to "top-level", but
first look at the examples, and run some of them!]

There are dozens of MLAB commands and hundreds of MLAB
functions waiting to be used. In essence, MLAB is an
interpreter for a high-level mathematical language and you
use MLAB by specifying purposeful sequences of MLAB commands
to accomplish your end. (As a practical matter, you will
probably often enter these commands in a text-file to
construct a re-runnable 'script' called a do-file.)

You can define a function and graph it as follows.

 function f(x) = a*cos(b*x)*exp(-k*x)
 a = 1; b=4; k =.5
 v=1:10!100
 m= points(f,v)
 draw m
 view

Note 1:10!100 = 1:10:.0909090909, and 1:10:.0909090909 means
the column vector of values from 1 to 10 in steps of size
.0909090909 (So can you guess what 1:10!100 means in 'plain
English'?)

Also note points(f,v) = v&'(f on v), and v$'(f on v) means
the column-wise concatenation of the matrix v with the
same-sized column vector consisting of the values of f
computed on the values in v.  (What do you think the
operator & does as opposed to &' ?  What do you think v$'7
is?)

You can read-in 110 data values from a file into a 2-column
matrix as follows.  The result is a 55 row by 2 column
matrix.

 d = read("filename",55,2)

Taking the rows of the matrix d as (x,y) data-points - with
error in the y-values - where these data points are
"modeled" by the function f, defined above, you can estimate
the unknown parameters a,b,k as follows.

 fit(a,b,k), f to d

You can use estimated weights for the various data points in
d based on a moving-variance estimation function ewt as
follows.

 fit(a,b,k). f to d with wt ewt(d)

You can graph the data and the "fit" as follows.

 delete w  /* to discard any previous picture */
 draw d linetype none, pointtype circle
 draw points(f,d col 1) color green
 view

You can look at the symbolic derivative of f and graph it as
follows.

 type f'x
 draw points(f'x, d col 1) color red
 view

Note MLAB can use symbolic-derivatives when derivative
values are needed during curve-fitting, or solving ODEs.

You can fit (or just solve) differential-equation-defined
models in MLAB, so that chemical kinetics and physiological
and compartmental models, etc.  can be handled.  [Look at
the MLAB examples that are available when you run MLAB.]

Try this:  

 a=3.14159e200
 b= -(10e201)
 type a, b, a*b, a^2, b^2

Now try that with any other computational program you have
access to.  (This behavior is often useful in
curve-fitting. Can you see why?)

Note, you can probably see that you need to have the MLAB
manuals available because there is so much in MLAB that you
will miss otherwise. You can find a link within the web-site
www.civilized.com that offers the option to download the
MLAB manuals in PDF format.  [There is a somewhat helpful
command "help" that you can use to access some reference
material for MLAB on-line, but looking at the .pdf Reference
Manual is better, and looking at examples in the MLAB
Applications Manual is sometimes even better.]

The directions for installing MLAB on your PC are given at
the end of this document.

---------------------------------------------------------------

The MLAB Executable Directory and the MLAB Working Directory:

There are two important directories (or "folders") that you
must(!)  be aware of when running MLAB.  The first is the
"MLAB executable directory", and the second is your "current
working directory".

The "MLAB executable directory" is that directory where the
MLAB executable program file (and other MLAB system files)
are stored.  This directory is established by the MLAB setup
program which is run when MLAB is installed.  Generally,
this directory is C:\MLAB\ unless you specify some other
directory to the setup program.  In any event, you MUST know
the full path and the name of this directory.  You should
write it on a piece of paper and tape it to your computer.
(but in case you don't, MLAB prints-out this full directory
name when it is run.)

Your "current working directory" is that directory where you
want to get your "input" and write your log-file and other
output, at least for "today".

When you run MLAB and ask it to execute a do-file (an MLAB
script,) or read a data-file, then, unless you specify a
specific path as part of the file-name (or set the FILEDIR
variable,) the current working directory will be the place
that MLAB looks for such files. Thus the directory where you
keep do-files and data-files for some project is the
directory that you want to make your current working
directory when you want to deal with that project.

There is a third important directory called your "home
directory".  For XP, this is C:\Documents and
Settings\[username]\, for Win7, this is C:\Users\[username].
Your home directory is where you should keep all your
personal files and subdirectories that you create for
various purposes such as an MLAB "project".  There is also a
bunch of directories that Windows puts in your home
directory.  Most of these are useless and annoying and can
be deleted, but your personal Desktop subdirectory is
vitally important.

---------------
How to Run MLAB


In a Unix/Linux system, MLAB is run by starting a
"terminal-emulator" program (like xterm) and then 'cd'-ing
to the directory that you want to be your working directory,
and then running MLAB by typing "MLAB" at the
'command-line'. ('cd' stands for 'change directory'.)

You can run MLAB the same way in a Windows system
(almost). You start a so-called DOS window (also called a
"command-prompt" window in XP and later,) and set the
'volume' (e.g. C:) and 'cd' to your desired working
directory, and then run MLAB by typing "MLAB" as the next
command.  In this case, the working directory is established
as you want it, i.e., as the directory you have 'cd'-ed to.
Note, however, unlike in Unix, in Windows MLAB puts its own
"console" window on the screen wherein all MLAB commands are
entered and printed, and where text-output occurs.  Thus the
DOS window is only used to get MLAB started with the desired
current working directory.

Also, note that to run MLAB from the "command-line" in
either Unix or Windows, you must(!) have the MLAB executable
directory in your PATH environment variable, or else you
must specify the fully-qualified executable-file name in
order to run MLAB (e.g. C:\MLAB\MLAB).

Without any 'cd' command, when you run MLAB from within a
DOS-window, your current working directory will start-out
being the directory specifed as the "start-in" directory
associated with the 'command-prompt' icon. By default, in
XP, this "start-in" directory is C:\windows\system32\. (In
Win7, the "start-in" directory is your home directory which
is C:\Users\[username]\.)  (It is thus generally a bad idea
to run MLAB in a DOS window without explicitly cd-ing to
where you want to be.)

[You will probably need to establish a "desktop shortcut
icon" for the cmd.exe program generally found in
C:\windows\system32\ for both XP and Win7 in order to
conveniently run the 'command-prompt' program; if you don't
do this, you will have to use the 'start-menu' to find and
execute the cmd.exe 'command prompt' program. How to do this
will be described below.]

There are two other ways to run MLAB in Windows.  One way is
to run the MS file-finder program (by clicking start ->
find, or start -> search) and "navigate" by clicking to the
MLAB executable directory, and then double-click on the MLAB
executable file, mlab.exe, to run it.  In this case, your
initial working directory will be the same as the MLAB
executable directory, and you will need to use the FILEDIR
control string in MLAB to "override" this.

The final way to run MLAB is to double-click on an MLAB
"shortcut" icon on the "desktop". (Such an icon will be
created when the MLAB setup program is run at the time MLAB
is installed - and you can create a shortcut icon yourself
at at any time as described below.)

When you run MLAB in this manner, your initial working
directory will be whatever is set as the "start-in"
directory associated with the 'icon' (Clicking on the icon
actually causes Windows to refer to a collection of files in
a directory called the "program group" directory that tell
it the full-name of the associated executable file, and
various other properties, including the "start-in"
directory.)

Generally the "start-in" directory associated with the MLAB
shortcut icon is the MLAB executable directory, but you can
change this by right-clicking on the MLAB shortcut icon,
then click on 'properties', and then, if necessary, click on
the "shortcut" tab in the window that pops up. Then you can
change the "start-in" text-field to whatever you want it to
be.  Thus, before you run MLAB, you could do this to set the
"start-in" directory, And you might re-do this whenever your
desired working directory is different from whatever is set.
In fact, you can set this text-field to
%HOMEDRIVE%%HOMEPATH% to always do an initial implicit 'cd'
to your home directory (use this exact text - it specifies
that the 'environment variables' HOMEDRIVE and HOMEPATH be
used.)  This is what we do to aid us in running MLAB.

However, another simple way to run MLAB with easy control of
your working directory is the first way: run the cmd.exe
'command-prompt' program by double-clicking on a
'command-prompt' icon you have created, 'cd' to the desired
directory where you want your data files and log files to be
for your current purposes, (generally this directory should
be either your home directory \Users\[username] or a
subdirectory of your home directory.) Then you type 'MLAB'
(or \MLAB\MLAB if you do not have your search-path set) to
run MLAB.

[Creating a subdirectory for data and log-files 
 for an MLAB "project":

Type the command 'mkdir subdirname' in your 'command-prompt'
window, after 'cd'-ing to the directory (such as
\Users\[username]) where you want the subdiretory to be.
"mkdir" stands for "make directory".]

[Adding C:/MLAB to your search-path: {This is awkward to do
due to design deficiencies!)  You can add the text "C:\MLAB"
to your search-path as follows.  Double click on your
"Computer" or "My Computer" system management program either
in the start menu, or a desktop icon (we have created such
an icon for convenience.) Then select "system properties",
and then "advanced" (it is hard to see - look at all of the
window.) Then "enviroment" (which is also hard to see.) Then
scroll down to the "path" environment string and select it
and click on 'edit'. In the window for editing, click in the
string value of 'path', right-arrow to its end and insert
the text: ";C:\MLAB" (without the quotes, of course.)  click
on "Okay" or the equivalent, window by window all the way
out.]

[Creating a Desktop icon for running MLAB:

A shortcut is a "LNK" (link) file "pointing to" an
executable file.  To have a visible icon associated, the
.lnk file must be stored in a "desktop" directory where the
Windows program manager can "see" it and display an icon
corresponding to it. (Having such a shortcut icon for a
program allows the user to run the program by
double-clicking on the icon without going through the
start-menu.)

If you do not have a Desktop "shortcut" icon for running
MLAB, you can create one as follows.

(1) Double-click on "My Computer" or "Computer", found
either on the desktop or in the Start menu.  This runs the
file-manager program.

(2) Double-click "local disk (C:)" to display a listing of
the directory [C:\].  Look for the entry "mlab" for the mlab
directory.  double-click on this entry. (If you put MLAB in
another directory, you will need to "navigate" to
it. -remember you need to click IN the picture of a
directory entry, not its title.) This will display the files
in the mlab directory within the file-manager window.

[A note about filenames in Windows.  

 When you use Windows GUI tools to look at the files in a
 directory, you generally do not see the truth.  The Windows
 file manager and other such tools display file names
 without the so-called filename-extension showing. Thus the
 file named "dimer.do" is listed as "dimer".  More
 troublesome, the directory "mlab" is listed as "mlab", but
 so is the file "mlab.exe".  Because of this problem, you
 are better off using a "command-prompt" window, i.e., a
 so-called DOS-window, and the cd and dir commands to see
 what files are in a directory, since the dir command does
 tell the truth.

 You can fix this problem in Windows as follows.  

 (2.1) Run the "My Computer" or "Computer" function from the
 start menu (you should really put a shortcut link to "My
 Computer" on your desktop and rename it "file finder".)

 (2.2) Click on "Tools" in the top menu and select the
 "folder options" option from the drop-down menu.

 (2.3) Click on the "View" tab in the window that appears.

 (2.4) scroll through the "advanced settings" list and
 uncheck the item "Hide extensions for known file types".

 (2.5) Click the "Apply" 'button' at the bottom of the
 window.

 This also has the benefit that Notepad will show full
 filenames to you - but you will only see all your files
 after you change the "file type" selection from "text
 documents" to "All files"(!)  This is a very troublesome
 problem! Be careful of this 'gotcha'.  ]

(3) Look for the executable program file "mlab.exe" in the
displayed mlab directory.  Right-click on the file-name
'mlab.exe'.  This will "pop-up" a menu. (Remember "mlab.exe"
appears as the name "mlab" in an unfixed file manager
window.]

(4) Click on the entry "Create Shortcut" in this menu.  This
will cause a "shortcut" file called "Shortcut to mlab.exe"
to be created in the mlab directory which is now displayed
in the file-manager window.

(5) Place the mouse on this "Shortcut to mlab.exe" file,
press the left-mouse-button and hold it and "drag" the
shortcut file to the "desktop" and release the mouse button.
For XP, this moves the "Shortcut to mlab.exe" file to
C:\Documents and Settings\[username]\ Desktop\.  For Win7,
this moves the "Shortcut to mlab.exe" file to
C:\Users\[username]\Desktop\.

Now you have an MLAB "shortcut icon" on the desktop, because
all files in all the Desktop directories are displayed on
the desktop.  You can run MLAB by double-clicking on this
icon.]

----------

In all cases, MLAB will write a session log-file in the
initial working directory!  This log-file will be called
"MLAB.LOG" (and the earlier log-files found there will be
renamed with the 'shifted' names MLAB1.LOG, MLAB2.LOG, etc.)
The session log-file is convenient. You can print it to
obtain a record of what you did.  You can extract text from
it to construct a do-file.  And you can review error
messages recorded there to "debug" an MLAB do-file. (You
will need to use some simple ASCII text editor such as
Notepad to do these things. You can run Notepad from within
MLAB by typing the command 'edit file "x"' where x is the
desired filename, qualified with the appropriate path.  [You
CANNOT use MS Word, or Wordpad!  These programs do not deal
with ASCII files - they use their own non-plain-text
format!])

Even if you start MLAB with the MLAB executable directory as
the initial working directory, you can, in effect, change
directories at will as you use MLAB.  There is a control
variable in MLAB called FILEDIR.  This variable is a string
of text that is prepended to every file-name you refer to in
your MLAB session!  [Your session log-file, MLAB.LOG, will,
however, be created in the initial working directory that is
set or that MLAB is given by Windows.  Setting FILEDIR has
no effect on where the log-file is.]

The FILEDIR variable starts-out as the empty-string.  Thus,
assuming FILEDIR is empty, if you type 'DO afile' in MLAB,
you are referring to the file afile.DO in your current
working directory.  If, however, you set FILEDIR - for
example: FILEDIR = "C:\project1" (or FILEDIR =
"C:\project1\") and then type 'DO afile', you will be asking
MLAB to execute the do-file 'C:\project1\afile.DO'. (Note
you need to know the DOS/Windows notation for specifying a
"path", i.e a fully-qualified directory on a specified
disk-partition 'volume'.)

The same prepending of FILEDIR occurs for all files you
refer to in MLAB.  Thus, for example, if you read a
data-file into a matrix with the command 'm =
read(dfile,120,2)', you are actually asking MLAB to read the
first 240 numbers found in the ascii-text file dfile.dat
within the directory specified by FILEDIR into the 120-row,
2-column matrix m.

There is an exception to the FILEDIR prepending rule in MLAB
for do-files.  If the MLAB control variable DOFILEDIR is set
to a non-empty string, then this string, rather than FILEDIR
is prepended to any do-file name that is specified to MLAB.
(This lets you access do-files in a particular directory
(specified by DOFILEDIR), while accessing other files in
some other directory (specified by FILEDIR.)

Thus, if you have your "project" data-files and do-files
stored in some specially-named directory (and it is
generally a good idea to work in this way,) then the first
command you should execute in MLAB is: "FILEDIR = "xxx",
where xxx is the fully-qualified path to the desired working
directory.  (Remember, you can change your working directory
at any time in an MLAB session by resetting the FILEDIR
string control variable appropriately.)

When you run MLAB, a "console" window is put on the screen,
and a smaller "menu" window is displayed in which you must
make a selection.  One choice is to run various
examples. (The first few times you run MLAB, you should look
at some examples!) Another choice is to go to "top-level",
which means that the menu window is removed from the screen,
and a "*" prompt symbol is displayed in the console window;
this prompt is waiting for you to enter an MLAB command.

Once you are at "top-level" and able to enter MLAB commands,
you can use the up-arrow and down-arrow keys to "scroll"
back through the previous MLAB commands and
responses. Hitting the Enter key will take you back to the
'current' prompt line. (You will note there are no scroll
bars on the MLAB console window; the arrow keys are the way
you "scroll" in the MLAB console window.)

In addition to looking at the previous lines in the console
window, you can "select" a line by hitting the Insert
key. This will cause the selected line to appear at the
'end' of the console window as the subject of a simple
single-line editor facility in MLAB.  You can then modify
the selected line, and hit the Enter key to execute it.
(When you enter an MLAB statement which is malformed in some
way, you will receive an error message and the malformed
line will be re-displayed in the MLAB single-line editor
facility where you can (attempt to) repair the error and
re-execute the line. You can also abort this 'editing' and
just go to a new '*'-prompt.)

=================================================

MLAB reads, writes or otherwise uses the following files or
types of files.

--------

1 - gxfonts.0: a binary file containing the 34 MLAB stroke
font definitions.  gxfonts.0 is a read-only file and found
in the directory where the MLAB program file is located.
The file is accessed whenever a title string or axis label
is to be drawn in the MLAB graphics window.

--------

2 - mlab.hlp and mlabref.hlp: files containing text used by
the MLAB HELP systems.  These read-only files are found in
the directory where the MLAB program file is located.
mlab.hlp is read when either the commands "HELP" or "HELP
topic" are given by the user.

The file mlabref.hlp is read when the user strikes the
F1-key to access the special Windows help presentation
system.  This text is not very useful, and it fails to work
for systems after XP (e.g. Vista, Win7.)

Also the content of the MLAB help-file, mlab.hlp, that is
accessed via the "HELP" command, although useful, is
incomplete, and sometimes wrong, so be sure to depend on the
MLAB Reference Manual as the final authority.

--------

3 - mlab.log, mlab0.log, mlab1.log, and mlab2.log: These are
ASCII text files containing the dialog of the current MLAB
session (in mlab.log) and the previous three MLAB sessions
(in the files mlab0.log, mlab1.log, and mlab2.log).  These
files are created by MLAB in the user's working directory
and are useful for seeing a record of MLAB results.  They
are also useful for constructing .do-files, since you can
copy the text in an mlab log-file and edit it to construct a
do-file. It is also useful to look at an mlab log-file to
aid in debugging an mlab do-file.  (Note: see the definition
of the system variable ECHODO, below.)

--------

4 - .do-files: An mlab do-file is an ASCII text file
containing comments and MLAB commands, i.e. a 'script' in
the mlab language. Such a 'script' can be repeatedly re-run,
and also easily changed as desired.  Constructing and
running a do-file is the preferred way of using mlab
whenever you have a relatively substantial computation to
do.  An example of a .do-file is the file DIMER.DO in the
directory containing the MLAB program file. Also there are
example .do-files in the MLAB\EXAMPLES\ directory.

A do-file can be generated with any ASCII text editor, such
as the MSWindows Notepad Accessory program.

DO NOT USE MS-WORD to create or change do-files or
data-files intended for use in MLAB unless you know how to
save files as ordinary text files!  MS-WORD generally
'saves' binary files. (and remember "rich" text is NOT
text!)- use Notepad or some other editor that can save plain
ASCII .txt files easily.

The MLAB command: [EDIT FILE filename.do] will run the
Notepad program for editing the specified new or existing
.do-file from within an mlab session. (When you run Notepad
from within MLAB in this manner, you do not have the
annoying problem of Notepad showing only *.txt files (and
directories) to select for editing.)

When running the Notepad editor via the EDIT FILE command
within mlab, the named .do-file is searched-for or created
in the directory specified by the path in the DOFILEDIR
control string. If DOFILEDIR is null, then the directory
specified by the path in the FILEDIR control string is
used. If FILEDIR is null, then the initial "start-in"
working directory is used.

Also, note that you can use Notepad directly by running it
from the start menu or by double-clicking on a desktop
shortcut icon for Notepad.)  But, beware! You must use the
initial Notepad startup window to set the "type" of file to
be input or accessed to the type "All Files" and you cannot
type the desired filename in with clarity.  There is a short
manual about how to use Notepad below.

MLAB .do-files contain MLAB commands and comments.  Comments
begin with the 2-character sequence: /* and are terminated
with the 2-character sequence: */.  Comments may span
multiple lines. Note, comments may NOT be embedded within
enclosing comments.

If more than one MLAB command appears on a line of a
.do-file, they must be separated by semicolons (;). (There
are other situations where terminating semicolons must be
used as well.)

An MLAB .do-file is executed by the command: [DO
filename.do]; that's why it is called a do-file.

The three scalar control variables DOSTEP, ECHODO, and
CASESW control aspects of general mlab execution and
.do-file execution.

If DOSTEP = k (a positive integer), then MLAB will
pause--waiting for a key to be struck by the user--after
every k lines in the .do-file have been executed.  Thus,
DOSTEP=1 will allow you to "single-step" through the
do-file, perhaps, looking for a line that cause an error
messsage.  If DOSTEP = 0, which is the default case, then a
DO-command will run the specified do-file without
interruption to completion, unless MLAB commands requiring
keyboard input are encountered, or there is an error
detected.

The control scalar ECHODO controls the "echoing" of do-file
commands to the screen and the log-file, mlab.log.  If
ECHODO = 0, then the .do-file is executed silently--no
commands are echoed to the screen or the log-file; if ECHODO
= 1, then the lines of the .do-file are echoed to the screen
but not the log-file; if ECHODO = 2, then the .do-file is
echoed to the log-file but not the screen; and if ECHODO =
3, the do-file is echoed to both the screen and the
log-file.

The control scalar CASESW controls the case-sensitivity of
MLAB names.  If CASESW = 0, then upper-case characters are
not distinguished from lower-case characters; all input is
converted to upper-case, except within quoted-strings.  If
CASESW = 1, no such conversion is done, except for control
variable names, mlab function names, and mlab reserved
syntax words, like "TYPE" or "DO".

The implications of using CASESW =1 are sometimes subtle,
especially with identifiers used as filenames, and we
reccomend you keep CASESW set to 0. (MLAB generaly tries
both upper-case and lower-case versions of filenames in an
attempt to not disappoint the user.)  .

--------

[How to Use MLAB]

The most convenient way to run MLAB when you have a
repetitive or a complex computation to do, is to setup a
do-file to do it.  (Remember, once you have read about how
to use the Notepad editor, you can do this by typing EDIT
FILE xdofile.do to create the do-file xdofile.do in your
working directory.)

You should be sure to put comments in your do-file to define
all the variables and functions, etc. and don't forget to
include comments specifying the units for all data where
this is important.

Note, it is convenient to give the commands "reset;
echodo=3" as the first commands in your do-file. Also,
remember the READ, READON, KREAD, and SREAD MLAB functions.
Another tip is that you can construct strings by
concatenation and you can execute such a string containing a
sequence of MLAB commands as a do-file!  For example, try
z=99; S="type "+"value of z:"+z; do S; and you can construct
more elaborate and useful examples.  [You should look at the
file startup.do and the do-files provided in the examples
sub-directory.]

After your do-file is written and saved on disk, you should
print it (You can use the MLAB command "PRINT FILE
xdofile.do" to get this listing.)  Then you should read your
do-file, add more comments, and verify that it does what you
want to the best of your ability.  (Remember to keep the
MLAB manuals close at hand.)  After you have iterated this
step as much as you feel is helpful, you should then run
MLAB and use the command "DO xdofile" to run your do-file.
(Remember you will need to have set-up any data-files or
other do-files that your do-file reads.

It is quite likely that there will be errors in your
do-file.  If you can see what the problem is, you can just
tyoe "EDIT FILE xdofile.do" and fix your do-file and resave
it on disk.  [You should leave the NotePad editor window
'open', so you can use it again in a few moments.]  Then you
can just type "DO xdofile" again, and see what happens.  You
can "flip" back and forth between NotePad and MLAB, until
your do-file is "debugged".

Sometimes it will be helpful to put TYPE statements in your
do-file so it will tell you the progress of execution.  This
is just one of the standard debugging devices that can
sometimes be helpful.

When your do-file is debugged, it can be run whenever you
wish by running MLAB and typing "DO xdofile".

Of course, for all your work with MLAB, you must be aware of
your current working directory and have FILEDIR set
appropriately.

One useful 'trick' you can use in a do-file is the command
[DO KLINE], 'KLINE' stands for "keyboard-line". When this
command is executed, MLAB will type a '>' prompt and wait
for input.  Whatever is typed will be executed as a do-file.
Note this is a good way to pause if you don't want to use
the undocumented MLAB PAUSE statement.  Also, you can use DO
KLINE in other ways like: [type "enter the desired function
as 'fct f(x)=...':"; do kline;] (Here are some other
experiments you should run.  [do dofilename], [do
"dofilename"], [do ksread()], [do ""+ksread()].)

MLAB Example Do-Files

All the examples that are available to you from the start-up
menu are just .do-files that are stored in the sub-directory
'EXAMPLES' in the MLAB executable directory (generally
C:\MLAB\).  You should go look at those .do-files (using
Notepad, or using the 'type' command or 'edit' command in a
DOS-window.)  You can also print any of these files using
the MLAB PRINT FILE command. To do this, type the MLAB
commands:

 filedir ="C:MLAB\EXAMPLES"
 type dir "*.do"  

Then select a file to print, such as dimerex.do,
and type 

 print file "dimerex.do"

One of the interesting things you will see in some of the
example .do-files is how to use the 'MENUCHOICE' and
'GETSTRINGS' MLAB functions that allow you to make your own
menus and to obtain text input. (See in particular the
Hogkin-Huxley Nerve Axon Model example.)  There are many
other interesting "lessons" to be found in the example
.do-files as well.

You can copy any of these do-files into your working
directory, and then modify it to construct your own do-file.
This is particularly appropriate if you want to do a
computation related to one of the example do-files.

--------

5 - .dat-files: .dat files are plain ASCII files containing
numbers to be read-in as data; the READ command is used to
do this.  Examples of .dat-files appear in the
MLAB\EXAMPLES\ directory. (The READ command scans the
specified file for numbers given by ASCII characters in any
"standard" form, such as 123 or 12.34 or -3.1e12, etc.  All
other bytes are ignored; thus the mlab READ command can read
appropriate non-ASCII files too.)

As with .do-files, .dat-files can be created or modified
with any ASCII text editor, such as the MSWindows Notepad
Accessory program.  And, as with do-files, The MLAB command:
EDIT FILE <filename.dat> can be used to construct or change
a dat-file.

Note, the MLAB string variable DOFILEDIR only affects the
path for .do-files, and does not affect the location of
.dat-files so that .do-files and .dat-files can be read from
different directories.

A .dat-file can also be created using Notepad, or any other
program as long as it contains the numbers you want (and
only those numbers) in ASCII (i.e. .txt format.)  DO NOT TRY
TO READ MS-WORD or EXCEL FILES IN MLAB UNLESS YOU KNOW THEY
ARE TEXT FILES.  Files created by MS-WORD and by EXCEL are
generally not text files unless you know how to save them as
such, they are usually binary files. (and remember "rich
text" is NOT text!)- use Notepad or some other editor that
can save plain ASCII .txt files easily.)

The numbers in a .dat-file are read and stored as the
elements of a matrix M by using the READ command:

M = READ("filename.dat",nr)

This READ-command will read nr or fewer values from the file
filename.dat in the implicit directory (either specified by
FILEDIR or established at initial start-up.) The i-th
successively-read value is assigned to M[i] (so M will be a
one-column matrix.).

The input file will be scanned for numbers embedded in ANY
non-digit text.  However, you can prevent any text you want
from being scanned by enclosing it in "'s or by the
C-comment brackets /*, */.

When FILEDIR is null, the read command [M =
READ("C:\DX\DY\S.DAT", rr)] reads rr numbers from the file
C:\DX\DY\S.DAT into M as a single column of rr values. (If
the file does not contain rr numbers, then all the numbers
present will be read.)

Data matrices with nr rows and nc cols can be constructed
with the following command:

M = READ("filename.dat",nr,nc)

If a .dat-file contains values for more than one matrix, a
special version of the READ command can be used. the
READON command can be used sequentially, as:

M1 = READON("filename.dat",nr1,nc1)
M2 = READON("filename.dat",nr2,nc2)
.
.
.
MN = READON("filename.dat",nrn,ncn)

Each READON command continues reading in the input file
where the previous READON command left-off.

There are other MLAB data-input commands you should learn
about - notably the KREAD and KSREAD functions.

--------

6 - .ps or .lj-files: A .ps file is an ASCII file in the
Adobe PostScript graphics language.  A .lj file is a binary
file containing or Hewlett- Packard PCL language. Both forms
of output files are called "plot-files".  They contain the
printer commands for an MLAB graphics picture.

After creating an MLAB 'picture' (consisting of one or more
MLAB "windows" all within the main mlab graphics window,
using the DRAW command, etc.), the MLAB-command [PLOT] will
generate a plot-file in the current working directory. This
plot-file is either a file named MLABP#.PS containing
commands suitable for printing on either a
PostScript-capable printer or a printer on a computer with
appropriate conversion software like Ghostscript, or it is a
file named MLABP#.LJ containing HP PCL-GL/2 commands
suitable for printing on a GL/2-compatible printer.  The
symbol # denotes the next succesive integer in the sequence
0,1,2,... (e.g. the first PLOT command writes-out MLAB0.PS,
the next PLOT command writes-out MLAB1.PS, etc.)

If the MLAB control variable PLOTDEV is set to PSL (or "PSL"
- try typing PSL) then a .PS plot-file is created containing
a black and white, Landscape orientation Postscript picture.

If the MLAB control variable PLOTDEV is set to PSCL (or
"PSCL") then a .PS plot-file is created containing a color,
Landscape orientation Postscript picture.

If the MLAB control variable PLOTDEV is set to PSP (or
"PSP") then a .PS plot-file is created containing a black
and white, Portrait orientation Postscript picture.  This is
the preferred plotting mode for creating a .ps plotfile for
"embedding" in a document.

If the MLAB control variable PLOTDEV is set to PSCP (or
"PSCP") then a .PS plot-file is created containing a color,
Portrait orientation Postscript picture.

If the MLAB control variable PLOTDEV is set to HPLJ (or
"HPLJ") then a .PS plot-file is created containing a black
and white, Landscape orientation PCL-GL/2 language picture.

An MLAB .PS plot-file is a so-called 'Encapsulated
Postscript' file suitable for embedding in a "document" file
such as an MSWord file, or a .tex file by respecifying the
size of the picture in your document file.  You may change
the name of your .PS file to be a .eps file which is
sometimes required.  The 'encapsulated PostScript' file,
thus created by renaming can be "imported" to Microsoft
Office (Word, PowerPoint, Excel) or TeX 'documents'
(i.e. files).

For example, to add the MLAB graph in the file MLABP0.EPS to
an MSWord document, position the text cursor in the MS Word
document where the graph is desired, goto the "Insert" menu,
select "Picture" from the drop-down menu, select the
"FromFile" option, select the MLABP0.EPS in the resulting
FileSelect dialogue box, and then select "Convert File From
Encapsulated PostScript".

An MLAB .PS file is just a text file, and you can look at it
and change it with any ASCII text editor program.  For
example, you can "open" the plot-file (MLABP0.PS say) with
the MLAB command: EDIT FILE MLABP0.PS),

Note the fifth line in the file contains the text defining
the bounding box given in 'point'-units (1 inch = 72 points)
that encloses the graphical image:

--------

7 - .lst files: ASCII files containing MLAB data names and
data.

The MLAB PRINT command:

PRINT [name1,name2,....] in <filename.lst>

generates an ASCII text file named 'filename.lst' in the
current working directory containing the MLAB data names
name1, name2, etc. and their corresponding values.

If the mlab control variable NAMESW = 0, then the MLAB data
names are suppressed in the output file.  This provides a
convenient way, for example, to "export" an MLAB matrix to
another computer program that accepts ASCII data files.

Note, the MLAB command:

PRINT FILE <filename>

sends a command to the local printer, to print the named
file in the current working directory.

--------

8 - .sav files: A .sav file is a binary file containing
"saved" MLAB data names and values.

The entire current state of MLAB, including all control
variables and user-created curves, windows, functions,
matrices, scalars, etc., can be saved in a .sav file in the
current working directory by the command:

SAVE IN <filename.sav>

The saved state of MLAB can then be restored at any other
time and in any other MLAB session by typing the command:

USE <filename.sav>

The SAVE command can also be used to save specific MLAB data
structures, such as an MLAB graphic window named Q and a
scalar vaule named B by listing the specific data items to
be stored; for example:

SAVE Q,B IN <filename.sav>

The window can be restored in a later MLAB session by typing
the command:

USE <filename.sav>

.SAV files are binary files; they can not be edited directly
with ASCII editors and are not exchangeable across different
types of computers; i.e. a .SAV file from Windows MLAB can
not be easily transferred to a non-Intel Macintosh version
of MLAB due to the "endian" conflict.

The pre-defined .sav-file DW.SAV defines the elements of the
default MLAB graphics window, W, and provides an example of
a .sav file.  DW.SAV is generated by giving the MLAB
commands (we do this via a do-file):

WINDOW 0 TO 10, 0 TO 10 ADJUST WNICE IN W;
XAXIS 0:10!6&'0 LABEL 0:10!6 LABELSIZE .015 FFRACT OFFSET (-.01,-.025) \
FFRACT FORMAT (-3,5,0,0,2,0) PT UTICK IN W;
YAXIS 0&'0:10!6 LABEL 0:10!6 LABELSIZE .015 FFRACT OFFSET (-.09,-.01) \
FFRACT FORMAT (-3,5,0,0,2,0) PT RTICK IN W;
FRAME COLOR VIOLET IN W;
IMAGE COLOR BLUE IN W;
SAVE W IN DW

When drawing in MLAB without specifying the target MLAB
"window", the default MLAB-"window", W, will be used. MLAB
obtains W by USE-ing it from DW.SAV.

-------

9. - Printing Files on a Windows system.

The MLAB command:

PRINT FILE <filename>

sends a command to the local printer, to print the named
file in the current working directory.

The MLAB PRINT FILE command works for ASCII files, such as
.dat or .lst files, and it also works for .lj files if you
have a directly-attached HP PCL-language printer (most
printers understand the PCL language.)

This also works for .ps files if you have a
directly-attached Postscript-language printer.  (If not, you
may need to use a web-browser to view .ps files generated by
MLAB.  You may be able to print them via the web-browser
program.  Also, if MSWord is properly programmed with the
analog of the Ghostscript Postscript to PCL converter, you
may be able to view a .ps file via MSWord.)

Also, you can send a file to your printer to be printed with
the command "COPY <file> LPT1:" given in a DOS command
window.  The file must be an ASCII text file, or in a native
language of the printer.

========================

Some More Information about Using MLAB

1. How to draw and plot a 3-D surface picture.

You may want to see a surface (a graph of some function
f(x,y), or a parametrically-defined surface of the form
(x(s,t), y(s,t),z(s,t)) for example.) When that surface is
the surface of a single-valued function, a useful way to
"see" it is to look at a corresponding contour map. See the
contour-map example: conex.do, found in the MLAB examples
directory reached from the MLAB start-up menu.

A "fancier" way to view a surface is to generate a
perspective 3D view of the surface. An example of how to do
this is found in the example do-file: torex.do located in
the examples sub-directory (For Win7, generally this is
/Users/[username]/Desktop/mlab/examples/).

The DRAW command described earlier for ordinary 2D graphs
can also be used to create 3D perspective views of 3
dimensional data.  The simplest 3D graph is a simple plot of
a set of 3 dimensional points in which each point is drawn
with a specified point-type symbol.  For example, consider a
set of 100 points with random coordinates.  Such a set can
be created with MLAB with the following command:

   M = SHAPE(100,3,RAN ON 0^^300)

Then the command:

   DRAW M POINTTYPE DOT3D LINETYPE NONE

creates the 3D window, W3, with a dot at each point given in
the data matrix, M.  Other 3D graphics point-types include:

    CROSS3D - this draws a 3D cross at each point,
    "char" -  this draws the given quoted ASCII character 
              (such as "x") at each point..

When you enter the command:

   VIEW

MLAB displays a default 3D perspective view of the points.
The default 3D perspective view is a view of the data as it
would appear in the viewfinder of a camera placed at a
suitably-chosen position and pointed in a suitably-chosen
direction.  The default position and direction of the
"camera" are determined as follows: first, find the limits
of the bounding box for all 3D points, lines, curves, and
surfaces: (xmin<=x<=xmax, ymin<=y<=ymax, zmin<=z<=zmax) with
box-dimensions x1=(xmax-xmin), y1=(ymax-ymin),
z1=(zmax-zmin) on the sides parallel to the x,y, and z-axis,
respectively.  The center of the box is at
(xcenter=xmin+x1/2, ycenter=ymin+y1/2, zcenter=zmin+z1/2).

When the VIEW command is first given, the initial view drawn
is that seen in the 'viewfinder' of a camera positioned at
(xcenter,ymax+y1,zmax) with its lens pointed in the
direction which results from right-hand-screw rotating a
unit vector which is initially parallel to the z-axis by 105
degrees about the x-axis.  The camera's initial viewing
angle is 90 degrees.

After MLAB displays the initial 3D perspective view, a
double-arrow prompt, >>, is printed.  At this stage, MLAB is
awaiting a 3D view command.  Striking the Enter key without
giving a 3D viewing command will terminate the viewing
command input at once, and return to the usual MLAB command
prompt, *.

There are eleven 3D perspective view commands that modify
the camera position and pointing direction.  These are:

DOLLY K - which moves the camera forward in the view
          direction 

TRUCK K - which moves the camera to the right of the view
          direction

RAISE K - which moves the camera up from the view direction

PAN A - which rotates the camera about the vertical axis

TILT A - which rotates the camera about the horizontal axis

TWIST A - which rotates the camera about the viewing axis

TRACK - which rotates the camera so as to point to the
        origin

TURN A - which right-hand-screw rotates the camera about the
         center of the 3D bounding box (x1,y1,z1)

ZOOM A - which changes the angle of view ORIGIN - which
         moves the camera to the origin, looking up the
         z-axis

RESET - which automatically returns the camera to the
        initial view

In these commands, A is an angle in degrees [0:360] and K is
a number of "relative-box" units such that the main diagonal
of the bounding box is 1 relative-box unit.  Fore example,
DOLLY -.5 would move the camera backward in the viewing
direction by .5 relative-box units.

There are also 3D graphics commands for adding or removing
graphical 'elements' of the 3D MLAB "window"; for example,
the bounding box can be drawn with the command:

      BOX

or can be erased with the command:

      NO BOX

In addition to the commands listed above, there are more
than 75 other 3D graphical commands for manipulating the
'elements' of the 3D perspective MLAB window.  See the MLAB
Reference Manual and MLAB Graphics Examples Manual for
further discussion.

MLAB has seven line-types for 3 dimensional graphics.  These
are:

   NONE
   NEEDLES
   SEQUENCE
   ALTERNATE
   MARKER
   NET
   HIDDEN

As seen in the example above where we drew points using
LINETYPE NONE, the line-type NONE draws no line segments.
The NEEDLES line-type draws line-segments from each point in
the 3D data matrix, say (x[i],y[i],z[i]), to the bounding
box floor at (x[i],y[i],0).  The SEQUENCE line type draws
line-segments from the i-th data point to the (i+1)-th data
point for all the 3D data points.  This line-type is of use
when drawing the 3D perspective view of a space curve.  The
ALTERNATE line type draws line-segments between every other
pair of 3D data points; i.e. between the first and second,
third and fourth, fifth and sixth, seventh and eighth data
points, etc.

The result of a MARKER line-type is similar to the MARKER
line-type used for 2D data.  The values of the first row of
the 3D data matrix define a 'marker' value.  As line drawing
proceeds sequentially from a 3D data point to the following
3D data point, if the marker value is encountered in column
1 then no line-segment is drawn and the sequential drawing
of line-segments is started anew until the next marker value
is found.

The line types NET and HIDDEN are used for graphs of 3D data
in which the data describe a surface.  The surface may be an
explicit function of two variables with data
{(x[i],y[j],f(x[i],y[j])), for i=1,2,...,nx and
j=1,2,...,ny} or the surface may be defined parametrically,
in the form {(x(s[i],t[j]),y(s[i],t[j]),f(x[i],t[j])), for
i=1,2,...,nx and j=1,2,...,ny}.

For an example you may define a function of two variables:

    FCT F(X,Y) = (x^2+y^2)/2 + x^2*y-y^3/3

and then generate a grid of x and y values:

    M = CROSS(-2:2:.2,-2:2:.2)

and then evaluate the function F at each grid point:

    M COL 3 = F ON M

and then graph the data with the NET line-type:

    DRAW M LINETYPE NET
    VIEW

the resulting 3D perspective graph shows an image resembling
a wire mesh with each point of the grid connected to its
four nearest grid neighbors.

The HIDDEN line-type for 3D perspective graphs corresponds
to the NET line-type except that "quads" are filled-in with
color and parts of "quads" on the surface that are obscured
by intervening quads of the surface are not seen!  The
HIDDEN linetype is demonstrated in the TOREX.DO do-file in
the examples subdirectory.

The command CMD3D can be used to specify 3D graphics
commands; this is particularly useful in do-files.  You
simply give a sequence of desired 3D graphics commands
deparated by semicolons [;] in a quoted-string as the
argument of the CMD3D 'function'.  For example,

    CMD3D("TRACK; DOLLY .5")

given in a do-file (or even at 'top-level' before the VIEW
command) will have the same result as typing the commands

    TRACK; DOLLY .5
    
at the <<-prompt.

You will want to experiment and read the MLAB Reference
manual about all the 3d, hidden-surface, and other viewing
commands and options.

If you are "plotting" an MLAB hidden-surface picture, you
should use PLOTDEV = PSCL (PSCL stands for
Postscript-color-landscape.) This will render your picture
correctly on both a color PostScript printer, and on a black
and white PostScript printer (via grey-scale dithering
matching the specified colors.)  Using PLOTDEV = LJ2L
specifies that a "raw" plot file for a PCL-language printer
be created.  A PCL-language plot-file cannot (currently) be
used to render an MLAB hidden-surface picture.

========================

How to Get and Install MLAB for Windows

You get a copy of MLAB by going to www.civilized.com and
following the indicated links to come to the page for
downloading the MLAB "package" file for Windows, (or for
OSX, or for Linux.)

When you click on [Click here to download MLAB via http
protocol] at the appropriate page at www.civilized.com, your
browser will begin the download process of a file called
zmlab.exe (for Windows.)  This file is a "self-extracting"
WinZip file containing the various MLAB
files. ('self-extracting' means the file zmlab.exe starts
with an executable program that, when executed, unpacks the
remaining compressed content of the zmlab.exe and writes
these files to a specified directory on the disk.)

When downloading MLAB in Firefox and installing MLAB after
downloading, you will see a sequence of windows.

[1.]  "Opening zmlab.exe" window

The first window that you get will be an "Opening zmlab.exe"
window produced by Firefox; this window says: "You have
chosen to open zmlab.exe. Would you like to save this file?"
You must click on [Save File]. ("Opening" is a misnomer -
they mean "Downloading".)

Firefox will then download the file zmlab.exe into the
directory that has been previously specified as your
"download directory".  (This is sometimes incovenient; it
would be better if Firefox had retained the option to
explicitly ask where you want a download file to go at each
download.)

By default your 'download directory' is C:\Documents and
Settings\[username]\My Documents\Downloads\ for Win-XP and
C:\Users\[username]\Downloads\ for Win7.  However it is
better if you reset your download directory to \Desktop, so
that you can 'see' what you have downloaded on the
desktop. (You do this in Firefox by going to Tools ->
Options, and then entering your desired download directory
name.) (You need to have "Administrator" privileges to set
your download directory to \Desktop and to download into
it.) You need to do this before you download files, of
course.
  
[2.] Firefox "downloads" window.

This Firefox-produced window reports the recently-downloaded
files, with zmlab.exe as the first entry, together with a
"completion bar" showing the download progress.  After the
download is complete, this window remains on the screen.

The next step you want to do is to run the self-extracting
file zmlab.exe that has just been downloaded.  This starts
the process of installing the MLAB prgram.

You can run the self-extracting file zmlab.exe by
double-clicking on the zmlab.exe entry in the Firefox
"downloads" window.

(One can also run zmlab.exe in various other ways.  You can
run zmlab.exe by double-clicking the icon for zmlab.exe on
the desktop (if you downloaded to a Desktop directory,) or
by using "Computer" or "My Computer" or some other means to
display whatever your download directory is, and
double-clicking on the filename zmlab.exe shown there to run
it.)

When the user runs the zmlab.exe program (by whatever
means,) another sequence of windows will be "generated".

[3.] Firefox "Open executable file" warning window

(You will only see this window when zmlab.exe is run from
the Firefox Download List Window.)

Firefox displays this window and asks "are you sure?"
because you are trying to run the downloaded program
zmlab.exe, and Firefox wants to make sure you understand you
are running a downloaded program. [Click OK].  Running
zmlab.exe is really running the WinZip Self-extractor
program appearing at the "front" of zmlab.exe.

If you run zmlab.exe by some other means, this "open
executable file" window will not appear.

[4.] Windows "open file-security warning" window.

This window (produced by the Windows OS) says "publisher not
verified, are you sure?"  At this point you are trying (or
still trying) to run the WinZip Self-Extractor program, and
zmlab.exe is not a registered application known to
Windows. [Click RUN].  (This happens because our WinZip
self-extractor program does not have a registration with
Microsoft, and we do not know how to get or use the "key"
that makes this window not appear.)

[5.] WinZip Self-Extractor window for zmlab.exe.

When the WinZip Self-Extractor program runs to "unzip" the
various MLAB files in the 'tail' of zmlab.exe, it displays
this WinZip dialog window.  This window has an editable
text-entry field titled "unzip to folder" with a "browse"
button in which the user can specify the directory where
MLAB is to be installed.  The default specified there is
"\MLAB".  (You may change the MLAB directory to another
name, or even another path, if you wish, but we recommend
you leave it alone.)  [Click "Unzip"]

[6.] WinZip Self-Extractor completion window.

WinZip reports 52 files "unzipped" successfully. [Click OK]
The Civilized Software setup.exe program that was included
among the downloaded and unzipped files is now run by the
WinZip Self-Extractor program.

[7.] Windows Install-As-Administrator Window

(You will only see this Windows-produced window when NOT
running as Administrator on WinXP/Win2K.  On Win7, we do a
"personal" install, and this window never appears).

On XP, if you do not have "administrator" privileges, 
(i.e. if you are logged in as a limited user), then before 
the setup.exe program is started, then an 
Install-As-Administrator window will be displayed by
Windows.  This window offers two choices:

  1. Run as hostname/user, or
  2. Run as administrator (the username Administrator and
     the corresponding password is required).

If you are logged-in with administrator privileges, then
this window is not displayed.

Now, after responding to the options offered (assuming the
Install-as-Administrator window is presented,) the setup.exe
program will be executed.

If you select option 1 and continue as "hostname\user", then
the MLAB setup program runs and it asks again whether you
want to terminate and re-login as administrator, or
continue.  If you continue, MLAB is installed with an MLAB
shortcut .lnk file placed in the user's desktop directory.

If you select option 2, you will be asked to supply the
Administrator password, and then the MLAB setup program
runs. MLAB is installed with an MLAB shortcut .lnk file
placed in the system desktop directory.

On Win7, we do not know how to "overcome" the access-control
features that prevent us from creating an MLAB shortcut file
in \Users\Public\Desktop.  Thus we currently ALWAYS do a
"personal" install where setup.exe places the MLAB shortcut
file in the user's desktop directory.

[8.] "DOS" command window.

This window may be obscured by your browser window, and you
should either minimize or move your browser window to see
this window or just click in this window to bring it "to the
front."

This window appears when the setup program is run. We see a
"DOS" command window because setup.exe is a "console"
application which will present output and receive keyboard
input in this "DOS" window.

When the MLAB installation process is finished, the setup
program will report some information in this window and ask
you to type any key to exit.  Read the output there and then
type a character.  When you strike a key as directed to
terminate setup.exe, then this associated console window
disappears.

Now you are done installing MLAB and you will have a
desktop "shortcut" icon showing there for later use.

Now you should maximize your browser window, if necessary,
and click on "go back to www.civilized.com".

Later, when you have finished with your browser, you can run
MLAB by double-clicking on the new MLAB desktop icon.


====================================

[Creating a Desktop icon for running MLAB:

If you do not have a Desktop "shortcut" icon for running
MLAB, you can create one as follows.

(0) If you do this on Win7 right after installing MLAB, when
you click on "start" to display the Start menu, you can find
the MLAB desktop shortcut icon in the list of "recently-run
programs in the start-menu.  All you need to do is to press
the mouse button down while positioned at the MLAB icon and
"drag and drop" it onto your desktop.

Otherwise:

(1) Double-click on "My Computer" or "Computer", found
either on the desktop or in the Start menu.  This runs the
file-manager program.

(2) Double-click "local disk (C:)" to display a listing of
the directory [C:\].  Look for the entry "mlab" for the mlab
directory.  double-click on this entry. (If you put MLAB in
another directory, you will need to "navigate" to
it. -remember you need to click IN the picture of a
directory entry, not its title.) This will display the files
in the mlab directory within the file-manager window.

(3) Look for the executable program file "mlab.exe" in the
displayed mlab directory.  Right-click on the file-name
'mlab.exe'.  This will "pop-up" a menu.

(4) Click on the entry "Create Shortcut" in this menu.  This
will cause a "shortcut" file called "Shortcut to mlab.exe"
to be created in the mlab directory which is now displayed
in the file-manager window.

(5) Place the mouse on this "Shortcut to mlab.exe" file,
press the left-mouse-button and hold it and "drag" the
shortcut file to the "desktop" and release the mouse button.
For Win-XP and Win7, this moves the "Shortcut to mlab.exe"
file to C:\Documents and Settings\[username]\ Desktop\.

Now you have an MLAB "shortcut icon" on the desktop, because
all files in all the Desktop directories are displayed on
the desktop.  You can run MLAB by double-clicking on this
icon.]

--------------

A Step-by-step Guide to using MLAB

1. Install MLAB

2. Establish a Desktop shortcut icon for MLAB, if necessary.

3. Run MLAB enter your name for display purposes, and verify
   that your current directory is listed in the MLAB console
   window as C:\mlab\


4. Use the first choice on the start-up menus window to look
   at the example menu and run the first few examples.

4. Exit MLAB.

5. Run MLAB

6.  Goto "top-level", and type the MLAB command: [type
    3+exp(2)].  Now type the command [3+exp(2)].

7. Now type the command ...

8. Run MLAB, go top-level, and type the command
   [edit file "toy.do"]  ...



========================

How to Use the Windows Notepad text-editor program


[You can use Notepad, but it is better to get a 
better text editor like emacs or vi
or many others.  Try to get an editor that tells the truth
about file names!  You must be able to edit ascii text.  You 
CANNOT use MS Word or any other non-ascii-text-editor.]

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