Annoying index variable changes inside for() cycle

ROOT
1

Hi all,

I’ve been banging my head over a small bug in this piece of code:

[code]// Set Branch
Short_t sum[16];
t->SetBranchAddress(“sum”, &sum);

// Cycle events
const Int_t nevts = (Int_t)t->GetEntries();
for(Int_t j = 0; j < nevts; j++) {

cout << j << endl;  // 1

if(j % 50000 == 0)
  cout << "Processing evt " << j << " of " << nevts << endl;

cout << j << endl;  // 2

t->GetEntry(j);

cout << j << endl; // 3

for(Int_t k = 0; k < npairs; k++) {
  if(sum[k] > 0)
h[k]->Fill(sum[k]);
}

cout << j << endl;  // 4

}
[/code]
On the output of this I get:
0
Processing evt 0 of 500
0

8519794
8519794

I really don’t have any clue of what might be wrong in this code…
I hope someone could help on this one…

Thanks in advance ,
Rui

2

Hi,

I think you meant to use:

Short_t sum[16]; t->SetBranchAddress("sum", &(sum[0]), "sum[16]/S");

Cheers,
Philippe.

3

Nope, that gives an error that the function SetBranchAddress(bla bla bla) doesn’t exist, possible candidates are…

Meanwhile I tried reading all branches by order:
Short_t adc[32] = {0}
t->SetBranchAddress(“adc”, &adc);
Short_t sum[16] = {0}
t->SetBranchAddress(“sum”, &sum);
Double_t a[16] = {0}
t->SetBranchAddress(“a”, &a);

and, with no further modifications, it started working…

Strange world we live in…
But thanks for your prompt reply!

Rui

4

Oups … I mis-read (SetBranchAddress vs just Branch) :frowning:

In your original code what is ‘npairs’?

Philippe.

5

Is defined in a header file like this:

static const Int_t npairs = 15;

Rui

6

[quote]and, with no further modifications, it started working…
[/quote]After re-reading your messages, I am unsure what constitute working or not.
Anyway I assume that the problem is now gone.

Philippe.