Error in SetBranchAddress

ROOT
1

Hi,

The error is : Error in <TTree::SetBranchAddress>: The pointer type given "Double_t" (8) does not correspond to the type needed "vector<double>" by the branch: m_nl_j

Part of the code is:

vector<double> nm_nl_j;
datatree->SetBranchAddress("m_nl_j",&(nm_nl_j[0]));

Thanks!

2 
vector<double>* nm_nl_j;
datatree->SetBranchAddress("m_nl_j", &nm_nl_j);
3

Hi,
What is the difference between vector<double>* nm_nl_j and vector<double> nm_nl_j ?
Thanks!

4

Ehm… The former is pointer, the later is not.

5

Hi,
Isn’t the first element of a vector a pointer as well?
Thanks!

6

Here the first element of a vector is a double, because it is vector<double>.

7

Ahh… sorry… the array name is a pointer to its first element… I got confused.
Anyways, will (*nm_nl_j)[i] be able to get the ith element of the vector?
Just wanted to clarify this… there is no error with this command…
Thanks!

8

No, it is not.

Yes.

But it will be easier to work with references, I think:

vector<double>* nm_nl_j_;
datatree->SetBranchAddress("m_nl_j", &nm_nl_j_);
for (Long64_t e = 0; e < datatree->GetEntries(); e++) {
	datatree->GetEntry(e);
	vector<double>& nm_nl_j = *nm_nl_j_;
	// use nm_nl_j 
}
9

Any reason why this causes segmentation violation?

   vector<double>* nm_nl_j;
   double* nnjet;

   datatree->SetBranchAddress("m_nl_j",&nm_nl_j);
   datatree->SetBranchAddress("njet",&nnjet);
    Long64_t ientry=0;

    for (ientry=0; ientry < 100; ientry++)
    {
         datatree->GetEntry(ientry);

         cout<<*nnjet<<endl;

         for (Int_t i=0; i<*nnjet;i++)
         {
              cout<<(*nm_nl_j)[i]<<endl;        
         }
     }

Thanks!

10

Try double nnjet; instead.
(And don’t change datatree->SetBranchAddress("njet",&nnjet);)

11

Hi,

It does give an output, but the moment output ends, a new root promt opens with error of segmentation violation and also hangs the current session due to which I have to close the terminal and reopen again… (Also, I changed the cout<<*nnjet to cout<<nnjet )

`…2
85.2737
58.1586
3
148.254
75.6262
99.6121
1
83.4105

root [2]
*** Break *** segmentation violation
`

Thanks!

12

You don’t need a nnjet branch, std::vector stores its own size.

vector<double>* nm_nl_j_;

datatree->SetBranchAddress("m_nl_j", &nm_nl_j_);
Long64_t ientry = 0;

for (ientry=0; ientry < 100; ientry++)
{
    datatree->GetEntry(ientry);
    vector<double>& nm_nl_j = *nm_nl_j_;

    cout << nm_nl_j.size() << endl;

    for (Int_t i = 0; i < nm_nl_j.size(); i++)
    {
        cout << nm_nl_j[i] << endl;        
    }
}
13

I agree, but I am getting segmentation violation even with this command…

  
    double nnjet;


    datatree->SetBranchAddress("njet",&nnjet);
    Long64_t ientry=0;

    for (ientry=0; ientry < 100; ientry++)
    {
         datatree->GetEntry(ientry);
         cout<<nnjet<<endl;
     }

Thanks!

14

double nnjet;

Could you upload .root-file and minimal complete script?

15

Hi,

Here are the files…

code.C (897 Bytes)
nfile_81.root (823.8 KB)

Thanks!

16

Ah. Completely forgot. The pointer shall be initialized:
vector<double>* nm_nl_j = 0;

17

Ahh… now it works…
Thanks a lot!

18

You may point it to an existing object:

vector<double> nm_nl_j;
vector<double>* nm_nl_j_ = &nm_nl_j;

datatree->SetBranchAddress("m_nl_j", &nm_nl_j_);

And then use nm_nl_j[i] instead of (*nm_nl_j)[i].

1 Like
19

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