  The following lists are the
pre-defined functions available
in the POLYGRAF. All of these
functions can be used directly
in the POLYGRAF model equation
and line equation editor.
  All the pre-defined functions
are designed to handle both
columns (COLUMN) and scalars
(FLOAT).
  All computations are done in
double precision with IEEE
arithmatics.
  In the function prototypes,
words such as COLUMN and FOAT
indicate data type and should
not be entered in the function
call. For the function name
itself, there is no case
differences. i.e. abs(), ABS(),
Abs() and AbS() are the same.
  All functions defined in
POLYGRAF have only one argument.

abs(): Absolute value.
    COLUMN y = abs(COLUMN x);
    FLOAT y = abs(FLOAT x);

acos(): Inverse cosine.
    COLUMN y = acos(COLUMN x);
    FLOAT y = acos(FLOAT x);

bessel(): Bessel function of the
    first or second kind, of
    order 0, 1 or N.

cdfn(): Cumulative density
    function of normal (gaussian)
    distribution (integral from
    -infinite to x).
cdfnc(): Complement of cumulative
    density function of normal
    distribution (integral from
    x to +infinite).
ceil(): Rounds up, toward positive
    infinite.
degtorad(): Convert from degree
    to radians (radians=PI/180
    degrees).
floor(): Round down, toward
    nagative infinite.
gamma(): Gamma function.
length(): Number of elements in
    a column.
loggamma(): Natural log of gamma
    function.
radtodeg(): Radians to degrees
    (degrees =180/PI radians).
round(): Rounds to nerest integer.
trunc(): Truncate values to
    integer.
unit(): Unit function.
step: Step function.
sign: Sign function.