Substracting Constant Value from all bins in Root Histogram

[fernades]

Hello everyone,

So, I’m trying to fit a set of data, but before I do this, I need to substract the histogram from 1.

For example, this is how my definition looks like N = 1 - G, where G is a histogram I aready created(no issues with that.)

Now, I will like to subtract histogram G from 1. Any help?

This is what I have tried so far and I feel like it’s not the best way to do;

auto Lab =new TH1F("Lab",
           "All events: Lab vs. Time; Time in seconds; Lab",
           1000,
           0,
           50);
  ifstream inp; float x;
  inp.open("Lab1.txt");
  for (int i=1; i<=1000; i++) {
    inp >> x;
   Lab->SetBinContent(i,x);
  }
Lab->Add(G ,  -1); 

Thanks

[couet]

@fernades

Lab->Add(G ,  -1); 

This does: Lab = Lab - G is it what you want ?

[fernades]

Hello Couet,

Yes, Lab = Lab - G is what I want, Lab is an arbitrary number of say 1 or 100.

In the Lab1.txt, I just filled the arbitrary number of about 1000 entries.

Is there any way to substracting arbitrary numbers from Histogram taking into account all the bins?

Thanks.

[couet]

@fernades

Lab is an arbitrary number of say 1 or 100.

No, Lab is an histogram (see help)

[fernades]

Okay, but please, how can I do something of say 1 - X, where X is the histogram?

[couet]

See the various Add methods

[Axel]

Sorry for the late reply! You should be able to use this:

hist->Scale(-1);
TH1 one("one","1");
hist->Add(one);