index ff50865c77459c839b115154c58338695d180321..74ac4ad40751ad898c783bd0185034c7673a0507 100644 (file)
-=head1 NAME
+=head1 NAME
rrdgraph_rpn - About RPN Math in rrdtool graph
=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.
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
delay t0
<--------------->
delay t1
- <--------------->
+ <--------------->
delay t2
<--------------->
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<>