Weights with user defined functions

Scott Sampson (scott@znev03.desy.de)
Sat, 15 Nov 1997 16:58:12 +0100 (MET)


Hi,

I want to use a function to control the weighting of histograms projected
from an ntuple. i.e. I define some function

float weight(float var) { .... return weight;}

and then when I project the histogram I use this function and a variable
from the ntuple:

nt->Draw("x>>h1","weight(z)")

where x and z are ntuple variables. The problem is that I get an error
message

Unknown name : "weight(z)"

Now this does work if I use some library routine like sin(z). How can I
define my own weighting functions? Thanks,

Scott Sampson
scott@znev03.desy.de