Hi @couet thank you…I think I didn’t write gPad->Update(); before the TPaveStats *stat = (TPaveStats*)gamma->GetListOfFunctions()->FindObject("stats");

Now it is working!
Is there a way to write the day instead of the number? I mean 24/02 instead of 1, 25/02 instead of 2 etc?

Hi @couet Then isn’t it possible to write the days?

Anyway, I’m trying to fit by a logistic function. It looks like that the fit follows the points shape, but the values of parameters and the X^2 are so big

thank you @couet it works, but it doesn’t work adding the fit (I think we need 2 x variables, the first one are the numbers to make the fit the second one are the dates to print on the plot). Anyway, don’t worry…it isn’t a problem to have the number instead of the data…

I think it will be difficult to fit the logistic function to that data. There is no data which show the flattening you would expect with such function. You might try setting some bounds and good initial value to get better results, but it will not probably give you a good chi2. Instead you will get a better fit with an exponential.
I attach a corrected macro where I get a converged fit using some parameter limits

I also read @moneta macro, it works, but it is just the fit, there isn’t the prevision for next days. I tried to modify @moneta’s macro following @smbat advice about the parameters and trying to print the prevision for exponential and logistic function…but the macro doesn’t works fine, I just get an exponential function

Here is your macro corrected for some errors
Also, as suggested by @smbat, I have relaxed the first parameter of the logistic function. The fit gives a slightly better chi-square for a very high value. I guess one needs more data (hopefully showing the good slowing down behaviour) and we can then maybe get a better constraint on that parameter.

thank you @moneta. Last question in the box stat I read the fit parameters of the logistic function. Given that there are two fits, is it possible to have a second box for the exponentional function too?
I tried , but it doesn’t work…

Ps. One more question, i see you wrote that data must be printed on the top…but the looks like covered by functions …