X-Git-Url: https://git.tokkee.org/?a=blobdiff_plain;f=program%2Fdoc%2Frrdgraph_rpn.pod;h=74ac4ad40751ad898c783bd0185034c7673a0507;hb=40bf5441006c8924dcd46bd7edbbcbf85b8b377b;hp=ff50865c77459c839b115154c58338695d180321;hpb=5c59b1e8ada366bb9ff6f57a954633c7e871d406;p=rrdtool-all.git

diff --git a/program/doc/rrdgraph_rpn.pod b/program/doc/rrdgraph_rpn.pod
index ff50865c..74ac4ad4 100644
--- a/program/doc/rrdgraph_rpn.pod
+++ b/program/doc/rrdgraph_rpn.pod
@@ -1,4 +1,4 @@
-=head1 NAME  
+=head1 NAME
 
 rrdgraph_rpn - About RPN Math in rrdtool graph
 
@@ -69,7 +69,7 @@ Z<>
 
 =item Comparing values
 
-B<MIN, MAX> 
+B<MIN, MAX>
 
 Pops two elements from the stack and returns the smaller or larger,
 respectively.  Note that I<infinite> is larger than anything else.
@@ -107,11 +107,24 @@ B<ATAN>
 
 Arctangent (output in radians).
 
+B<ATAN2>
+
+Arctangent of y,x components (output in radians).
+This pops one element from the stack, the x (cosine) component, and then
+a second, which is the y (sine) component.
+It then pushes the arctangent of their ratio, resolving the ambiguity between
+quadrants.
+
+Example: C<CDEF:angle=Y,X,ATAN2,RAD2DEG> will convert C<X,Y>
+components into an angle in degrees.
+
 B<FLOOR, CEIL>
 
 Round down or up to the nearest integer.
 
-Z<>
+B<DEG2RAD, RAD2DEG>
+
+Convert angle in degrees to radians, or radians to degrees.
 
 =item Set Operations
 
@@ -140,7 +153,7 @@ average is essentially computed as shown here:
                        delay     t0
                  <--------------->
                          delay       t1
-                     <--------------->  
+                     <--------------->
                               delay      t2
                          <--------------->
 
@@ -177,9 +190,9 @@ function cannot be used in B<VDEF> instructions.
 
 B<COUNT>
 
-Pushes the number 1 if this is the first value of the data set, the 
-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 
+Pushes the number 1 if this is the first value of the data set, the
+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<>