X-Git-Url: https://git.octo.it/?a=blobdiff_plain;f=doc%2Frrdgraph_rpn.pod;h=b2a84dd9daa4a1c55d3a354e9de577918e94cc14;hb=a6d79528b4812e8eb3927dba3cdd42e6ca51b287;hp=74ac4ad40751ad898c783bd0185034c7673a0507;hpb=a6f5f1b6b90008e73fa57882276bc643c039bb09;p=rrdtool.git

diff --git a/doc/rrdgraph_rpn.pod b/doc/rrdgraph_rpn.pod
index 74ac4ad..b2a84dd 100644
--- a/doc/rrdgraph_rpn.pod
+++ b/doc/rrdgraph_rpn.pod
@@ -15,11 +15,12 @@ takes as many elements from the stack as needed. Pushing is done
 implicitly, so whenever you specify a number or a variable, it gets
 pushed onto the stack automatically.
 
-At the end of the calculation there should be one and only one
-value left on the stack.  This is the outcome of the function and
-this is what is put into the I<vname>.  For B<CDEF> instructions,
-the stack is processed for each data point on the graph. B<VDEF>
-instructions work on an entire data set in one run.
+At the end of the calculation there should be one and only one value left on
+the stack.  This is the outcome of the function and this is what is put into
+the I<vname>.  For B<CDEF> instructions, the stack is processed for each
+data point on the graph. B<VDEF> instructions work on an entire data set in
+one run. Note, that currently B<VDEF> instructions only support a limited
+list of functions.
 
 Example: C<VDEF:maximum=mydata,MAXIMUM>
 
@@ -29,7 +30,7 @@ of your RRD script.
 Example: C<CDEF:mydatabits=mydata,8,*>
 
 This means:  push variable I<mydata>, push the number 8, execute
-the operator I<+>. The operator needs two elements and uses those
+the operator I<*>. The operator needs two elements and uses those
 to return one value.  This value is then stored in I<mydatabits>.
 As you may have guessed, this instruction means nothing more than
 I<mydatabits = mydata * 8>.  The real power of B<RPN> lies in the
@@ -126,6 +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>
@@ -138,6 +143,13 @@ 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.
 
+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>
 
 Create a "sliding window" average of another data series.
@@ -195,8 +207,6 @@ number 2 if it is the second, and so on. This special value allows
 you to make calculations based on the position of the value within
 the data set. This function cannot be used in B<VDEF> instructions.
 
-Z<>
-
 =item Time
 
 Time inside RRDtool is measured in seconds since the epoch. The
@@ -230,7 +240,7 @@ Z<>
 
 =head1 VARIABLES
 
-These operators work only on B<VDEF> statements.
+These operators work only on B<VDEF> statements. Note that currently ONLY these work for B<VDEF>.
 
 =over 4
 
@@ -272,6 +282,18 @@ finite numbers and are always more than the I<Unknown> numbers.
 
 Example: C<VDEF:perc95=mydata,95,PERCENT>
 
+=item LSLSLOPE, LSLINT, LSLCORREL
+
+Return the parameters for a B<L>east B<S>quares B<L>ine I<(y = mx +b)> 
+which approximate the provided dataset.  LSLSLOPE is the slope I<(m)> of
+the line related to the COUNT position of the data.  LSLINT is the 
+y-intercept I<(b)>, which happens also to be the first data point on the 
+graph. LSLCORREL is the Correlation Coefficient (also know as Pearson's 
+Product Moment Correlation Coefficient).  It will range from 0 to +/-1 
+and represents the quality of fit for the approximation.   
+
+Example: C<VDEF:slope=mydata,LSLSLOPE>
+
 =back
 
 =head1 SEE ALSO
@@ -285,6 +307,6 @@ Make sure to read L<rrdgraph_examples> for tipsE<amp>tricks.
 
 =head1 AUTHOR
 
-Program by Tobias Oetiker E<lt>oetiker@ee.ethz.chE<gt>
+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>