[rrd-users] Clipping data with sequences of IFs in a CDEF. Can it be done ?

[Stanley Hopcroft]

Dear Ladies and Gentlemen,

I am writing to say that I'd hoped to clip data before graphing it with
something like

CDEF:clipped=x,UpperBound,GT,UpperBound,x,IF,LowerBound,LT,LowerBound,x,IF

(the intent is that clipped is x:  LowerBound <= x <= UpperBound. I
thought the CDEF would evaluate to
min(x,UpperBound),LowerBound,LT,LowerBound,x,IF. Perhaps this is what I 
should have done in the first place.)

I apologise if this is a RFTM especially so because of the great number
of carefully written tutorials.

The CDEF above does not do what I'd hoped.

The pair of CDEFs

CDEF:cliptop=x,UpperBound,GT,UpperBound,x,IF
CDEF:clipped=cupper,LowerBound,LT,LowerBound,cliptop,IF

work quite happily.

Obviously I have missed something fundamental.

I have only checked this in the August snapshot of the dev branch.

I am yet another happy and grateful customer. Why don't they hand out
Nobel prizes for people who make wonderful things such as this ?

Yours sincerely.

-- 
------------------------------------------------------------------------
Stanley Hopcroft
------------------------------------------------------------------------

'...No man is an island, entire of itself; every man is a piece of the
continent, a part of the main. If a clod be washed away by the sea,
Europe is the less, as well as if a promontory were, as well as if a
manor of thy friend's or of thine own were. Any man's death diminishes
me, because I am involved in mankind; and therefore never send to know
for whom the bell tolls; it tolls for thee...'

from Meditation 17, J Donne.

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