Fit routine method or fit function method

ROOT
,
1

I have drawn a histogram that has a number of peaks and now i want to fit each peak.
Let’s start with only one peak. I have chosen one of the peaks.
I also have given initial parameters and it has plot the given function according to the given parameters.

So it is not the correct fitting.It is only a kind of simulation.
What i want is when i give initial parameters to it. It should my function according to those given parameters.

Help me!!!

_ROOT Version:6.14
_Platform:Ubuntu
Compiler: Not Provided

2

It is difficult to help you without an example showing what you are doing. I can suggest you to look at the fit tutorials. Many of them deal with the same kind of problem you are explaining here.

3

hist.C (1.7 KB)
Above is my C program.

peaks
peaks1122×687 8.08 KB

Above is showing energy spectrum from the given data.
Now i want to fit 3rd peak in the histogram.
peak
peak1122×687 7.72 KB

This is not showing the exact fitting curve it is just showing the range that i have given in g3 function in the code.
How is it possible to fit this peak so that it automatically takes the parameter?

4

What is hist.C supposed to do ? I see you define gaussians and draw them. But there is no fitting (and no data) .
May be @moneta would have an idea about what you are trying to show with that code.

5

Hi ,

The macro looks fine to me, just add the code for fitting:

h1->Fit(g1,"R+"); 
h1->Fit(g2,"R+");
h1->Fit(g3,"R+");  
...

The fits should work if you set the function parameters and range that make sense. Note that I am using the option “+” to add all the functions to the histogram

Lorenzo

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