Two questions/problems about TH1-s:
- The errorbars are wrong. They are displayed as sqrt(sum of weights)
but they should be (sum of weights)/sqrt(N) where N is the number of
entries in the bin. The workaround of using a TGraphErrors and
doing it myself is quite cumbersome.... And worse, it would prevent
the user from using the canvas editor to manipulate it as usual.
I realize this requires an additional int per bin -- do we need
another class (analogous to TGraphErrors)? Or better, a new function
AccumulateErrorbars(bool) that allocates the additional array and
causes Fill() to fill it and Draw("E?") to draw errorbars correctly
(and if never called things can work as they do now).
- The option to Draw "E1 X0" still draws the X errorbars. But
gStyle->SetErrorX(0) does remove them.
I'm using a TH1D if it matters (probably not). This is Root 5.12 on Linux.
Tom Roberts
Received on Sun Jul 15 2007 - 06:31:35 CEST