[Insight-users] LBFGSBOptimizer: bounds for BSplineDeformableTransform?

[Luis Ibanez]

Hi Chris,


The type of the Bounds in the LBFGSBOptimizer is an *Array*
of doubles:


   Line 70:   typedef Array<double>  BoundValueType;


So,
you have a bound value peer component of the array of
parameters passed to the optimizer.


In other words, if you are optimizing in a parameteric space
of 215 dimensions, (e.g. a vector fo 215 components), then
you pass also an array of bounds with 215 compoents, where
each bound value correspond to one of the parameters in
the vector.


So if you have a BSplineDeformable transform with 215
parameters, you must pass two bound arrays to the optimizer.

     optimizer->SetLowerBound( minimumBounds );
     optimizer->SetUpperBound( maximumBounds );

where minimumBounds and maximumBounds are respectively two
arrays of 215 components.



   Regards,


       Luis



----------------------------
Christoph Niedermayr wrote:
> Hi all!
> 
> I'm confused about how to use the LBFGSBOptimizer with a
> BSplineDeformableTransform...
> 
> Facts:
>  - LBFGSBOptimizer optimizes a set of variables within given bounds
>  - A bound is a scalar of type double.
>  - The parameters of the BSplineDeformableTransform are N-dim vectors.
> 
> Question:
>   What is the meaning of a scalar bound in respect to a vector-type
>   variable? The length of the vector?
> 
> tia,
> Chris
> 
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