Ok, that's what I feared.
Its a pity that the way via the in-file branch descriptor is not working
for arrays. With this method you could create a large variety of trees
with a simple script just by modifying the input file (very handy for
testing). Guess I have to go the way you proposed and put the
flexibility into the macro
Thanks
Rene Brun wrote:
> TTree::ReadFile is using the names that you specify in the branch
> descriptor.
> If you want to have the branch name with a different name, procedd as
> follows:
> TTree* Tree = new TTree( "Test", "Test" );
> int Len;
> double ar[2];
> Tree->Branch("Len",&Len,"Len/I");
> Tree->Branch("Array",ar,"Array[2]/D");
> Tree->ReadFile( "Array2.txt");
>
> in this case you should remove the branch descriptor line from your
> Array1.txt
>
> Rene Brun
>
> Thomas Lauf wrote:
>> Thanks for the quick answer!
>> I can reproduce your lines also on my machine, no problem here.
>> But a thing that does not work is this:
>>
>> root [0] TTree* Tree = new TTree( "Test", "Test" );
>> root [1] Long64_t RetVal = Tree->ReadFile( "Array1.txt" );
>> root [2] Double_t Array[2];
>> root [2] Tree->SetBranchAddress( "Array", &Array )
>> Error in <TTree::SetBranchAddress>: unknown branch -> Array
>>
>> I can read out the tree branch this way
>> root [3] Tree->SetBranchAddress( "Array[2]", &Array )
>> root [4] for( Int_t i=0; i<3; ++i ) {
>> Tree->GetEntry(i);
>> cout << Array[0] << " " << Array[1] << endl;
>> }
>> 1.1 2.1
>> 3.1 4.1
>> 5.1 6.1
>>
>> Somehow the name of the branch gets handled differently.
>> When the branch descriptor is "Array[2]", it is displayed this way
>> under TTree::Print(), but not under TTree::Show().
>> TTree::Scan() delivers in my case:
>>
>> root [5] Tree->Scan()
>> Error in <TTreeFormula::TTreeFormula>: Index 2 for dimension #1 in
>> Array[2].Array[2].Array is too high (max is 1)
>> ************************************
>> * Row * Len * Array[2]. *
>> ************************************
>> * 0 * 2 * *
>> * 1 * 2 * *
>> * 2 * 2 * *
>> ************************************
>> (Long64_t)3
>>
>> but only under ROOT 5.25, using 5.20 I get
>> root [3] Tree->Scan()
>> ***********************************************
>> * Row * Instance * Len * Array *
>> ***********************************************
>> * 0 * 0 * 2 * 1.1 *
>> * 0 * 1 * 2 * 2.1 *
>> * 1 * 0 * 2 * 3.1 *
>> * 1 * 1 * 2 * 4.1 *
>> * 2 * 0 * 2 * 5.1 *
>> * 2 * 1 * 2 * 6.1 *
>> ***********************************************
>> (Long64_t)6
>>
>>
>> Thomas
>>
>> Rene Brun wrote:
>>> I cannot reproduce your problem with any version of ROOT (I tried
>>> 5.22,5.25 and 5.26).
>>> The result of your 2 commands = tree.Print gives
>>>
>>> root [0] TTree* Tree = new TTree( "Test", "Test" );
>>> root [1] Long64_t RetVal = Tree->ReadFile( "Array1.txt" );
>>> root [2] Tree.Print()
>>> ******************************************************************************
>>>
>>> *Tree :Test :
>>> Test *
>>> *Entries : 3 : Total = 1621 bytes File Size
>>> = 0 *
>>> * : : Tree compression factor =
>>> 1.00 *
>>> ******************************************************************************
>>>
>>> *Br 0 :Len :
>>> Len/I *
>>> *Entries : 3 : Total Size= 634 bytes One basket in
>>> memory *
>>> *Baskets : 0 : Basket Size= 32000 bytes Compression=
>>> 1.00 *
>>> *............................................................................*
>>>
>>> *Br 1 :Array[2] :
>>> Array[2]/D *
>>> *Entries : 3 : Total Size= 705 bytes One basket in
>>> memory *
>>> *Baskets : 0 : Basket Size= 32000 bytes Compression=
>>> 1.00 *
>>> *............................................................................*
>>>
>>>
>>>
>>> and if you do, eg
>>> root [3] Tree.Show(0)
>>> ======> EVENT:0
>>> Len = 2
>>> Array = 1.1,
>>> 2.1
>>> everything is Ok
>>>
>>> Rene Brun
>>>
>>> Thomas Lauf wrote:
>>>> Hello,
>>>>
>>>> if I apply this little script
>>>>
>>>> {
>>>> TTree* Tree = new TTree( "Test", "Test" );
>>>> Long64_t RetVal = Tree->ReadFile( "Array1.txt" );
>>>> gROOT->ProcessLine("Tree->Print(\"toponly\"); > Array3.dat");
>>>> }
>>>>
>>>> on the file Array1.txt which looks like this
>>>>
>>>> Len/I:Array[2]/D
>>>> 2 1.1 2.1
>>>> 2 3.1 4.1
>>>> 2 5.1 6.1
>>>>
>>>> I would expect the resulting tree to have 2 branches named 'Len' and
>>>> 'Array' of which the second one is an array of doubles with length 2
>>>> and the file Array3.dat should look like this:
>>>>
>>>> ************************************************************************
>>>>
>>>> *Tree :Test :
>>>> Test *
>>>> *Entries : 3 : Total = 1601 bytes File Size =
>>>> 0 *
>>>> * : : Tree compression factor =
>>>> 1.00 *
>>>> ************************************************************************
>>>>
>>>> branch: Len 0
>>>> branch: Array 0
>>>>
>>>> The script passes with no errors but the branch containing the array
>>>> does not have the expected name, it is named 'Array[2]' as one can
>>>> see in the real output:
>>>>
>>>> ************************************************************************
>>>>
>>>> *Tree :Test :
>>>> Test *
>>>> *Entries : 3 : Total = 1601 bytes File Size =
>>>> 0 *
>>>> * : : Tree compression factor =
>>>> 1.00 *
>>>> ************************************************************************
>>>>
>>>> branch: Len 0
>>>> branch: Array[2] 0
>>>>
>>>> What went wrong? How can I get ROOT to name the branch 'Array'?
>>>> My research in the documentation so far was futile...
>>>>
>>>> I am using ROOT 5.20/00 on linux. I have tested this example also under
>>>> ROOT 5.25/02, but it failed there too.
>>>>
>>>> Thanks for any advice
>>>>
>>>> Thomas
>>>>
>>>
>>
>>
>
--
Dipl.Phys. Thomas Lauf
MPI Halbleiterlabor
Otto-Hahn-Ring 6
81739 Muenchen
Tel. : +49 89 839400 - 59
Fax. : +49 89 839400 - 13
Received on Tue Jan 12 2010 - 15:55:34 CET