=include name
-=head1 SYNOPSYS
+=head1 SYNOPSIS
I<E<lt>RPN expressionE<gt>> :=
I<E<lt>vnameE<gt>>|I<E<lt>operatorE<gt>>|I<E<lt>valueE<gt>>
Sine, cosine (input in radians), log, exp (natural logarithm)
+B<ATAN>
+
+Arctangent. Output in radians.
+
B<FLOOR, CEIL>
Round down,up to the nearest integer
=item MAXIMUM, MINIMUM, AVERAGE
Return the corresponding value, MAXIMUM and MINIMUM also return
-the first occurance of that value in the time component.
+the first occurrence of that value in the time component.
Example: C<VDEF:avg=mydata,AVERAGE>
Return the last,first value including its time. The time for
FIRST is actually the start of the corresponding interval, where
-LASTs time component returns the end of the corresponding interval.
+the LAST time component returns the end of the corresponding interval.
Example: C<VDEF:first=mydata,FIRST>
=item TOTAL
-Returns the rate from each defined timeslot multiplied with the
+Returns the rate from each defined time slot multiplied with the
step size. This can for instance return total bytes transfered
when you have logged bytes per second. The time component returns
the amount of seconds