[Insight-developers] some probable bug in itk::SingleValuedVnlCostFunctionAdaptor

[Luis Ibanez]

Hi Ashish,

You are right, the Adaptor should check first
for this pointer not to be NULL.

This is a known bug and was fixed on Monday March 7 2004.

You will find the log of the CVS commit in the following link:
http://www.itk.org/cgi-bin/viewcvs.cgi/Code/Numerics/itkSingleValuedVnlCostFunctionAdaptor.cxx?r1=1.11&r2=1.12&root=Insight&sortby=date

Please update your CVS checkout of ITK.


   Regards,



       Luis



--------------------------------------------------------------------
Ashish Poddar wrote:
> I was trying to use ConjugateGradientOptimizer in place of 
> RegularStepGradientDescentOptimizer, and it always crashes when it tries 
> to access {DerivativeType &input} whose value (as I traced back) comes 
> from the function { vnl_cost_function::f} in the call {this -> compute 
> (x, &f, 0);}
>  
> here the value of "g" which is a pointer is set to null, which causes 
> the crash... (if I did something wrong or interpreted something wrong, 
> please correct)
>  
> so probably this change needs to be incorporared in the compute function
>  
> (last 2 lines of the function)
> __ 
> _Current:_
> ConvertExternalToInternalGradient( externalGradient, *g );
> *f = static_cast<InternalMeasureType>( measure );
>  
> _Modified:_
> if (g) ConvertExternalToInternalGradient( externalGradient, *g );
> if (f) *f = static_cast<InternalMeasureType>( measure );
>  
>  
> with best regards,
> Ashish.
>  
> p.s. this took me 5-6 days to figure out the problem !! and if the 
> solution is not correct please do tell me..
> -- 
> Ashish Poddar
> Have an acceptable reason for accepting anything.
> Y:ashish_poddar | MSN:ashish_poddar at yahoo.com 
> <mailto:MSN:ashish_poddar at yahoo.com>
> 
> 
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