Re: automatic Streamer

From: Gerhard Brandt <gbrandt_at_mail.desy.de>
Date: Wed, 08 Jun 2005 15:17:21 +0200


Rene Brun wrote:

> Hi gero,
> 
> yes, you understood my point correctly. The new Streamer is more 
> efficient than the old one when it finds consecutive data members
> of the same type.

Hi Rene,

Can you quantify 'faster' and 'more efficient'? Are there some test results?

Thanks,
Gerhard

> Rene Brun
> 
> On Wed, 8 Jun 2005, Gero Flucke wrote:
> 

>> On Tue, 7 Jun 2005, Rene Brun wrote:
>>
>>> Hi Gero,
>>>
>>> If you have consecutive data members of the same type, the automatic
>>> Streamer is faster.
>>> In addition, the automatic schema evolution is only available with
>>> the automatic Streamers.
>>> We STRONGLY recommend to use the automatic Streamers.
>>
>>
>> Hi Rene,
>> thanks for explanation, just for being sure that I understand you
>> correctly:
>> By 'consecutive data members of the same type' you mean that class data
>> members are ordered by their type, e.g.
>>
>> class MyClass : public TObject{
>> Float_t fFloat1;
>> Float_t fFloat2;
>> Int_t fInt;
>>
>> ClassDef(MyClass)
>> }
>>
>> is (with 'new' Streamer) better than
>>
>> class MyClass : public TObject{
>> Float_t fFloat1;
>> Int_t fInt;
>> Float_t fFloat2;
>>
>> ClassDef(MyClass)
>> }
>>
>> Am I right?
>>
>> Cheers
>>
>> Gero
>>
>>> On Tue, 7 Jun 2005, Gero Flucke wrote:
>>>
>>>> Hi,
>>>> is there a general rule which automatically generated streamer
>>>> mechansim
>>>> is faster:
>>>> The (very) old one or the "new" introduced in ROOT 3.0 and activated
>>>> if I
>>>> have in my LinkDef.h
>>>>
>>>> #pragma link C++ class MyClass+;
>>>>
>>>> with the '+' in the end.
>>>>
>>>> Cheers
>>>>
>>>> Gero
>>
>>
>> --
>> -----------------------------------------------------------------------
>> Gero Flucke
>> 1a / 603
>> DESY
>> Notkestr. 85
>> 22607 Hamburg
>> +49-(0)40-8998-2454
>>

> Received on Wed Jun 08 2005 - 15:17:27 MEST

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