Re: [ROOT] GetParErrors()

From: Rene Brun (Rene.Brun@cern.ch)
Date: Thu Sep 19 2002 - 14:50:27 MEST


Hi Alberto,

I am a bit relunctant to implement this kind of interface in
more classes (I know that it is in TFormula and some other classes).
Passing a non const pointer as argument makes debugging more
difficult in case, for example, the user provided array
is not large enough.
A solution where the array is created internally by the Get function
is not a solution either because it confuses who is owning what.
One could imagine more sophisticated solutions where a high level
object, like TVector, STL vector is filled, but this is the door open
to an infinity of prototypes in a class with the result that
the interface looks more complex.

At least, this is my view. May be a majority thinks differently.
In this particular example with GetParErrors, why is the
existing prototype not sufficient? Do you want to change 
the errors ?

Rene Brun

On Wed, 18 Sep 2002, Alberto Garcia Raboso wrote:

> Hi ROOTers,
> 
> In TFormula, the method GetParameters() is overloaded as
> 	virtual Double_t* GetParameters() const
> 	virtual void GetParameters(Double_t* params)
> However, the method TF1::GetParErrors() has only one form
> 	virtual Double_t* GetParErrors() const
> 
> I find particularly useful the second prototype of GetParameters(), but
> it doesn't exist for GetParErrors()... Is it intended or just an
> oversight?
> 
> Cheers,
> 
> ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
> Alberto Garcia Raboso
> CERN / EP
> CH-1211 Geneva 23, Switzerland
> Office 40-2B-19 (+41 22 76 71626)
> E-Mail: Alberto.Garcia.Raboso@cern.ch
> ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
> Well, farewell, my hobbits! You should come safe to your own
> homes now, and I shall not be kept awake for fear of your
> peril. We will send word when we may, and some of us may yet
> meet at times; but I fear that we shall not all be gathered
> together ever again.
> 
>                       The return of the King. J.R.R. Tolkien
> ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
> 



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