X-Git-Url: https://git.verplant.org/?a=blobdiff_plain;f=doc%2Frrdgraph_rpn.pod;h=cf62c0800b918466f7e802dd4f8b0fd00184974a;hb=dc217fb6f3a8f03e4f643e42a84428d14747d7b2;hp=6e31ea6d09916eda496096b02f23acb5ad7d6002;hpb=c201fa0decdd835c7edbe19a221f5b7564c3e8cf;p=rrdtool.git

diff --git a/doc/rrdgraph_rpn.pod b/doc/rrdgraph_rpn.pod
index 6e31ea6..cf62c08 100644
--- a/doc/rrdgraph_rpn.pod
+++ b/doc/rrdgraph_rpn.pod
@@ -127,6 +127,10 @@ B<DEG2RAD, RAD2DEG>
 
 Convert angle in degrees to radians, or radians to degrees.
 
+B<ABS>
+
+Take the absolute value.
+
 =item Set Operations
 
 B<SORT, REV>
@@ -146,7 +150,7 @@ 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 +174,12 @@ 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>