Sharing an object between residual blocks.

[Gohteu Nuetah]

Hey everyone

I have a two all my cost functions have in common one rather performance expensive "buildup" of an object based on parameters they share. I wanted to know wether it is possible to have this object have built up once and share it between the different cost functions.

My code looks something like this:

struct C1{

//...

bool operator()(T const* const* parameters, T* residuals) const{

auto instance = reference->WithParameters(parameters[0]);

 

//...

}

}; 

struct C1{

//...

bool operator()(T const* const* parameters, T* residuals) const{

auto instance = reference->WithParameters(parameters[0]);

 

//...

}

}; 

Is there a way to have the instance computed just once every cycle?

[Adel Ahmadyan]

One solution would be to use the factory to create the cost function classes C1 and C2 and then define a shared pointer as a member in these classes.

class C1{

shared_ptr<data> sharedData;

public:

    bool operator() ...

    static ceres::CostFunction* Create(shared_tr<data>){

         return (new ceres::AutoDiffCostFunction<C1, ...>(new C1(data)));

    }

}

A more complete example is available at  https://github.com/openMVG/openMVG/blob/master/src/openMVG/sfm/sfm_data_BA_ceres_camera_functor.hpp