How to fill 2D from Ntuple?

William Love (love@bnl.gov)
Tue, 2 Feb 1999 17:25:58 -0500


Root experts (Valery gave up)

I am trying to dump two 2D arrays from an ntuple to two TH2F's so I
can subtract them. The arrays are 56X29 so I predefine the output arrays

TH2F hv6("hv6","fooey",56,-0.5,55.5,29,-0.5,28.5)

I then try to fill the array with

ntb->Draw("index:irad>>hv6","bzme*(index<29 && iphi==9)","lego")

If I inspect hv6 beforehand it is 56X29 as expected. After the fill
the array is 40X40 with the consequent mismatch of the binning and
the data. What am I doing wrong? I have the results of hv6.Dump()
both before and after the Draw if you want to look at them.

Bill Love