Imported upstream version 1.3rc4.

[pkg-rrdtool.git] / doc / rrdgraph_rpn.pod

diff --git a/doc/rrdgraph_rpn.pod b/doc/rrdgraph_rpn.pod
index 454f7367691a045fefa0ae1e1ce295d84eb5b299..aabd7383e43979ae6396d0fc210aa3c879a55563 100644 (file)
--- a/doc/rrdgraph_rpn.pod
+++ b/doc/rrdgraph_rpn.pod
@@ -66,6 +66,8 @@ mean that any value other than 0 is considered to be true.
 
 Example: C<A,B,C,IF> should be read as C<if (A) then (B) else (C)>
 
+Z<>
+
 =item Comparing values
 
 B<MIN, MAX>
@@ -89,12 +91,19 @@ will always return an I<unknown>
 Example: C<CDEF:a=alpha,0,100,LIMIT> will return I<unknown> if
 alpha is lower than 0 or if it is higher than 100.
 
+Z<>
+
 =item Arithmetics
 
 B<+, -, *, /, %>
 
 Add, subtract, multiply, divide, modulo
 
+B<ADDNAN>
+
+NAN-safe addition. If one parameter is NAN/UNKNOWN it'll be treated as
+zero. If both parameters are NAN/UNKNOWN, NAN/UNKNOWN will be returned.
+
 B<SIN, COS, LOG, EXP, SQRT>
 
 Sine and cosine (input in radians), log and exp (natural logarithm),
@@ -146,7 +155,7 @@ average, ignoring all UNKNOWN values in the process.
 
 Example: C<CDEF:x=a,b,c,d,4,AVG>
 
-B<TREND>
+B<TREND, TRENDNAN>
 
 Create a "sliding window" average of another data series.
 
@@ -170,6 +179,12 @@ average is essentially computed as shown here:
      Value at sample (t1) will be the average between (t1-delay) and (t1)
      Value at sample (t2) will be the average between (t2-delay) and (t2)
 
+TRENDNAN is - in contrast to TREND - NAN-safe. If you use TREND and one 
+source value is NAN the complete sliding window is affected. The TRENDNAN 
+operation ignores all NAN-values in a sliding window and computes the 
+average of the remaining values.
+
+
 =item Special values
 
 B<UNKN>
@@ -230,6 +245,8 @@ B<DUP, POP, EXC>
 Duplicate the top element, remove the top element, exchange the two
 top elements.
 
+Z<>
+
 =back
 
 =head1 VARIABLES
@@ -245,6 +262,12 @@ the first occurrence of that value in the time component.
 
 Example: C<VDEF:avg=mydata,AVERAGE>
 
+=item STDEV
+
+Returns the standard deviation of the values.
+
+Example: C<VDEF:stdev=mydata,STDEV>
+
 =item LAST, FIRST
 
 Return the last/first value including its time.  The time for