[rrd-users] RPN Confusion

Simone Felici s.felici at alpikom.it
Wed Dec 5 15:41:24 CET 2007


Ok, maybe discussed into archives, but I cannot find any solution.
Now I want to understood the RPN syntax to write my own graph with different colors.
I'm at this point... trying to determinate a stack value.

in example, changing color every 20 units.
The first CDEF is ok (0-20), it's an area:

also if ds>20 then C1=20, else C1=ds. And this goes to AREA
Until here, OK!

The second will be a stack (20-40).
if ds>40, then C2=20, elseif ds>20 then C2=ds-20 else C2=0

The last it's a stack too:
if ds>lastvaluelimit, then Cn=ds-lastvaluelimit, else Cn=0

I cannot write it into RPN, have no idea how to set elseif and make operations to variables only in the else case.
I've read the tutorial, it's not discussed how use multiple IF

Please :(

Simone Felici                    E-Mail: s.felici at alpikom.it
Divisione Tecnica                Tel:    0461 030 111
Alpikom S.p.A.                   Fax:    0461 030 112
v.Fersina, 23 - 38100 Trento     URL:    http://www.alpikom.it

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