====== Extracting channels from ROOT files ======

Overview: This script ({{:itk:channelextraction.py|}}) allows the user to print a list of problematic channels after running a test. The user inputs the ROOT file from the test, the specific histogram they would like to analyze, and must input the maximum number of hits possible in the channels. 

Instructions:
  * Download the package using the command 
<code bash>
wget https://atlaswww.hep.anl.gov/asc/wikidoc/lib/exe/fetch.php?media=itk:channelextraction.py -O ChannelExtraction.py
</code>
  * Once you have the package, make sure that you have already installed ROOT or can open the ROOT file from your test.
  * Open the script ''vim (or emacs/whatever text editor you use) ChannelExtraction.py''.
  * Input your ROOT file that contains the histogram from the test, the name of the histogram, and the maximum number of hits possible in all of the channels.
  * Save script.
  * Run script using ''python ChannelExtraction.py'' 
  * The information will be printed to the command line.

Script:
<code python> #This script allows the user to see the specific ouput for specific pixels on different electronic tests
  from ROOT import *

  #The user must input the root file, histogram, and the maximum number for bin content
  fileName = "~/calibData/TEST_NAME_0000RUN#/histos.root"  #For example: an analog test with run number 11 ~/calibData/ANALOG_TEST_000011/histos.root.
  histogramName = "Mod_94220425_Occupancy_Point_000"    #This is the corresponding histogram name for the analog test.
  maxValBin = 50     #This is the corresponding maximum hits for the analog test.

  #Do not modify the rest of the code, it should work given what the user has place above.
  test = TFile.Open(fileName)
  h = test.Get(histogramName)
  h.Draw("colz")
  for i in range(1, h.GetNbinsX()):
        for j in range(1, h.GetNbinsY()):
        binContent = h.GetBinContent(i, j)
        if binContent < maxValBin:
              print "*****************************"
              print "Pixel column (x): ", i
              print "Pixel row (y): ", j
              print "Number of hits: ", binContent
              print "*****************************" </code>