That's the problem. I had one rrd file with inpropper data. And when I used GE version, graph was O.K because
GE(unknown, known) = known ... :-((( Thanks for hint. And when someone else will need this - with Milan Obuch big help, this is solution, how to obtain the biggest value from the 3 inputs: DEF:x1=.... DEF:x2=.... DEF:x3=.... CDEF:biggest=x1,x2,GE,x1,x2,IF,x3,GE,x1,x2,GE,x1,x2,IF,x3,IF or much more efficient & readable: CDEF:biggest=x1,x2,GE,x1,x2,IF,DUP,x3,GE,EXC,x3,IF Problem solved, you can close the thread :-) -- Rado1 On Tue, Sep 24, 2002 at 11:44:41PM +0200, Alex van den Bogaerdt wrote: #> #> On Tue, Sep 24, 2002 at 06:40:58PM +0200, Radovan Turan wrote: #> #> > And this is problem. By manual page, "CDEF:y=x1,x2,MAX" is the propper #> > function to select maximum of the values x1 and x2. But "y" is leaved #> > "UNKNOWN". #> #> #> max(unknown,unknown) == unknown #> max(known,unknown) == unknown #> max(unknown,known) == unknown #> max(known,known) == known #> #> So, if either x1 or x2 (or both) are unknown, so will be the result. #> #> Solution: #> #> if (x1==unknown) #> then #> return x2 #> elsif (x2==unknown) #> then #> return x1 #> else #> return max(x1,x2) #> fi #> #> #> In RPN (may need some debugging which I didn't do!): #> #> x1,UN,x2,result_of_next,IF (this is the if-then) #> #> result_of_next: #> x2,UN,x1,result_next,IF (this is the elsif-then) #> #> result_next: #> x1,x2,MAX (in case both x1 and x2 are known) #> #> #> Combined: #> #> CDEF:y=x1,UN,x2,x2,UN,x1,x1,x2,MAX #> #> This function: #> #> f(unknown1,unknown2) == unknown2 #> f(known1,unknown2) == known1 #> f(unknown1,known2) == known2 #> f(known1,known2) == max(known1,known2) #> #> will return an unknown only if both x1 AND x2 are unknown. #> The original function will return unknown if x1 OR x2 are unknown. #> #> HTH #> Alex #> #> -- #> Unsubscribe mailto:[EMAIL PROTECTED] #> Help mailto:[EMAIL PROTECTED] #> Archive http://www.ee.ethz.ch/~slist/rrd-users #> WebAdmin http://www.ee.ethz.ch/~slist/lsg2.cgi #> -- Unsubscribe mailto:[EMAIL PROTECTED] Help mailto:[EMAIL PROTECTED] Archive http://www.ee.ethz.ch/~slist/rrd-users WebAdmin http://www.ee.ethz.ch/~slist/lsg2.cgi
