Misc documentation fixes by Alex van den Bogaerdt

[rrdtool.git] / doc / rrdgraph_rpn.pod

diff --git a/doc/rrdgraph_rpn.pod b/doc/rrdgraph_rpn.pod
index 21661ba..2e29112 100644 (file)
--- a/doc/rrdgraph_rpn.pod
+++ b/doc/rrdgraph_rpn.pod
@@ -9,7 +9,8 @@ I<RPN expression>:=I<vname>|I<operator>|I<value>[,I<RPN expression>]
 =head1 DESCRIPTION
 
 If you have ever used a traditional HP calculator you already know
-B<RPN>. The idea behind B<RPN> is that you have a stack and push
+B<RPN> (Reverse Polish Notation).
+The idea behind B<RPN> is that you have a stack and push
 your data onto this stack. Whenever you execute an operation, it
 takes as many elements from the stack as needed. Pushing is done
 implicitly, so whenever you specify a number or a variable, it gets
@@ -357,12 +358,13 @@ the number of seconds.
 
 Example: C<VDEF:total=mydata,TOTAL>
 
-=item PERCENT
+=item PERCENT, PERCENTNAN
 
 This should follow a B<DEF> or B<CDEF> I<vname>. The I<vname> is popped,
 another number is popped which is a certain percentage (0..100). The
 data set is then sorted and the value returned is chosen such that
 I<percentage> percent of the values is lower or equal than the result.
+For PERCENTNAN I<Unknown> values are ignored, but for PERCENT
 I<Unknown> values are considered lower than any finite number for this
 purpose so if this operator returns an I<unknown> you have quite a lot
 of them in your data.  B<Inf>inite numbers are lesser, or more, than the
@@ -370,6 +372,7 @@ finite numbers and are always more than the I<Unknown> numbers.
 (NaN E<lt> -INF E<lt> finite values E<lt> INF)
 
 Example: C<VDEF:perc95=mydata,95,PERCENT>
+         C<VDEF:percnan95=mydata,95,PERCENTNAN>
 
 =item LSLSLOPE, LSLINT, LSLCORREL
 
@@ -398,4 +401,5 @@ Make sure to read L<rrdgraph_examples> for tipsE<amp>tricks.
 
 Program by Tobias Oetiker E<lt>tobi@oetiker.chE<gt>
 
-This manual page by Alex van den Bogaerdt E<lt>alex@ergens.op.het.netE<gt>
+This manual page by Alex van den Bogaerdt E<lt>alex@vandenbogaerdt.nlE<gt>
+with corrections and/or additions by several people