This patch introduces a feature whereby rrdcached will disallow updates

[rrdtool.git] / doc / rrdgraph_rpn.pod

diff --git a/doc/rrdgraph_rpn.pod b/doc/rrdgraph_rpn.pod
index 5000d7a..aabd738 100644 (file)
--- a/doc/rrdgraph_rpn.pod
+++ b/doc/rrdgraph_rpn.pod
@@ -99,6 +99,11 @@ B<+, -, *, /, %>
 
 Add, subtract, multiply, divide, modulo
 
 
 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),
 B<SIN, COS, LOG, EXP, SQRT>
 
 Sine and cosine (input in radians), log and exp (natural logarithm),


@@ -127,6 +132,10 @@ B<DEG2RAD, RAD2DEG>
 
 Convert angle in degrees to radians, or radians to degrees.
 
 
 Convert angle in degrees to radians, or radians to degrees.
 

+B<ABS>
+
+Take the absolute value.
+

 =item Set Operations
 
 B<SORT, REV>
 =item Set Operations
 
 B<SORT, REV>


@@ -139,7 +148,14 @@ Example: C<CDEF:x=v1,v2,v3,v4,v5,v6,6,SORT,POP,5,REV,POP,+,+,+,4,/> will
 compute the average of the values v1 to v6 after removing the smallest and
 largest.
 
 compute the average of the values v1 to v6 after removing the smallest and
 largest.
 

-B<TREND>
+B<AVG>
+
+Pop one element (I<count>) from the stack. Now pop I<count> elements and build the
+average, ignoring all UNKNOWN values in the process.
+
+Example: C<CDEF:x=a,b,c,d,4,AVG>
+
+B<TREND, TRENDNAN>

 
 Create a "sliding window" average of another data series.
 
 
 Create a "sliding window" average of another data series.
 


@@ -163,6 +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)
 
      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>
 =item Special values
 
 B<UNKN>


@@ -240,6 +262,12 @@ the first occurrence of that value in the time component.
 
 Example: C<VDEF:avg=mydata,AVERAGE>
 
 
 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
 =item LAST, FIRST
 
 Return the last/first value including its time.  The time for