Hi Plamen,
reaching these limits usually means that your approach is wrong. What
are you trying to do?
Cheers, Axel.
Plamen Boutachkov wrote on 11/06/2009 02:57 PM:
> Hi David,
>
> I do not know enough about the root internal memory management. I was
> hoping that the swap of the machines will help.
>
> But then if the limit is the physical RAM of the machine why I can
> create
> TH2D *t = new TH2D("test","t",70000,0.,1.,70000,0.,1.)
> 70000*70000* 8 B = 36GB
>
> On the same machine 32 bit 4GB RAM I tried:
> TH2I *t = new TH2I("test","t",100000,0.,1.,100000,0.,1.)
> a 37GB histogram, it worked.
>
> Is there a difference how one and many histograms are handled in
> memory?
> Should one track the total memory spend for histograms and make sure it
> is bellow a given number?
>
> Thank you for the suggestion of THnSparse.
>
> Plamen
>
> On Fri, 2009-11-06 at 14:10 +0100, David Gonzalez Maline wrote:
>> Hi,
>>
>> Just some simple maths would help.
>>
>> 5001 xbins * 5001 ybins * 4bytes each bin * 40 histograms ~= 3.72 GB of
>> memory...
>>
>> Obviously in the second machine you don't get such an error until you
>> change the number of bins to a much bigger number. Consider using
>> THnSparse instead and/or reducing the number of bins.
>>
>> David
>>
>>
>> Plamen Boutachkov wrote:
>>> Hello,
>>>
>>> I need to create a large number of TH2I, this leads to a crash. Here
>>> is an example script which reproduces the problem:
>>>
>>> {
>>> Int_t nHistograms = 40 ;
>>> TH2I *h[nHistograms] ;
>>>
>>> for(Int_t nIndex = 0; nIndex < nHistograms ; ++nIndex ) {
>>> TString sHistogramNname = Form("h%d",nIndex);
>>> cout<<"Histogram Number:"<< nIndex << endl;
>>>
>>> h[nIndex] = new TH2I(sHistogramNname.Data(),sHistogramNname.Data()
>>> ,5001,0.,5000.
>>> ,5001,0.,5000.);
>>> }
>>> }
>>>
>>> executing the script gives:
>>>
>>> Histogram Number:0
>>> ...
>>> Histogram Number:29
>>> Histogram Number:30
>>> Error: Symbol G__exception is not defined in current scope
>>> scripts/test.C:11:
>>> Error: type G__exception not defined FILE:/tmp/test.C LINE:11
>>> *** Interpreter error recovered ***
>>>
>>> If I include the above loop in a stand alone program the error is:
>>> Histogram Number:0
>>> ...
>>> Histogram Number:30
>>> terminate called after throwing an instance of 'std::bad_alloc'
>>> what(): std::bad_alloc
>>> Aborted
>>>
>>>
>>> I can produce a similar error by executing:
>>>
>>> TH2D *t = new TH2D("test","t",30000,0.,1.,30000,0.,1.)
>>> Error: Symbol G__exception is not defined in current scope (tmpfile):1:
>>> Error: type G__exception not defined FILE:(tmpfile) LINE:1
>>>
>>> or
>>>
>>> root [0] TH2D *t = new TH2D("test","t",40000,0.,1.,40000,0.,1.)
>>> Error: Symbol G__exception is not defined in current scope (tmpfile):1:
>>> Error: type G__exception not defined FILE:(tmpfile) LINE:1
>>>
>>> On other hand creating a larger histograms:
>>>
>>> root [0] TH2D *t = new TH2D("test","t",50000,0.,1.,50000,0.,1.)
>>> or
>>> root [0] TH2D *t = new TH2D("test","t",60000,0.,1.,60000,0.,1.)
>>> or
>>> root [0] TH2D *t = new TH2D("test","t",70000,0.,1.,70000,0.,1.)
>>> works.
>>>
>>> I am running ROOT 5.24/00b on a 32bit machine with 3GB of memory.
>>>
>>> I tried the same on a 64bit machine, 24GB of memory, root Version
>>> 5.18/00b
>>> executing
>>>
>>> root [0] TH2D *t = new TH2D("test","t",30000,0.,1.,30000,0.,1.)
>>>
>>> does not give an error, but
>>>
>>> root [0] TH2D *t = new TH2D("test","t",40000,0.,1.,40000,0.,1.)
>>> Error: Symbol G__exception is not defined in current scope (tmpfile):1:
>>> Error: type G__exception not defined FILE:(tmpfile) LINE:1
>>>
>>> Regards,
>>> Plamen
>>>
>>> --
>>> -----------------------------
>>> Dr. Plamen Boutachkov
>>> Kernstruktur, GSI Darmstadt
>>> Planckstr. 1
>>> D-64291 Darmstadt
>>> Germany
>>>
>>> Tel: +49 6159-71-2436
>>> Fax: +49-6159-71-2898
>>> -----------------------------
>>>
>>>
>>>
>
>
Received on Fri Nov 06 2009 - 15:02:13 CET