Re: slow macro processing

Rene Brun (Rene.Brun@cern.ch)
Fri, 12 Feb 1999 07:56:28 +0000

Paul M. Eugenio wrote:
>
> Hi,
>
> In a macro I open ROOT file containing a TTree of TOjects, and then I plot some histograms for about 20k events. One of my branch objects contains a pointer to a TClonesArray and when I add code to iterate through the array I find that the processing time increases from seconds to minuets. I created the TBranches with split=1 which (I believe) will create sub branches. Is there a way to speed up the macro by setting some branch address to the TClonesArray?
>
> Thanks for any pointers...
>

Hi Paul,
Currently you cannot use split mode if one of your branches contains
a pointer to a TClonesArray. It is our intention to introduce a new
class
to allow an efficient implementation.
For the time being, instead of storing the pointer to the object
in the TClonesArray, store the index of this object in the array.
This will be far more efficient both in terms of storage volume
and speed.

Rene Brun