gurls::KernelChisquared< T > Class Template Reference

KernelChisquared is the sub-class of Kernel that builds the kernel matrix for a chi-squared model.

#include <chisquaredkernel.h>

Inheritance diagram for gurls::KernelChisquared< T >:

Collaboration diagram for gurls::KernelChisquared< T >:

List of all members.

Public Member Functions
GurlsOptionsList *	execute (const gMat2D< T > &X, const gMat2D< T > &Y, const GurlsOptionsList &opt) throw (gException)
	Builds the symmetric kernel matrix of matrix X for a chi-squared model.
Static Public Member Functions
static Kernel< T > *	factory (const std::string &id) throw (BadKernelCreation)
	Factory function returning a pointer to the newly created object.

---

Detailed Description

template<typename T>
class gurls::KernelChisquared< T >

Definition at line 58 of file chisquaredkernel.h.

---

Member Function Documentation

template<typename T >

GurlsOptionsList * gurls::KernelChisquared< T >::execute	(	const gMat2D< T > &	X,
		const gMat2D< T > &	Y,
		const GurlsOptionsList &	opt
	)		throw (gException) [virtual]

Parameters:

X	input data matrix
Y	labels matrix
opt	not udes

Returns:

kernel, a GurslOptionList with the following fields:

• type = "chisquared"
• K = the kernel matrix

Implements gurls::Kernel< T >.

Definition at line 76 of file chisquaredkernel.h.

{
    const int n = X.rows();
    const int t = X.cols();


    gMat2D<T>* K_m = new gMat2D<T>(n, n);
    T* K = K_m->getData();

    const T epsilon = std::numeric_limits<T>::epsilon();

    set(K, (T)0.0, n*n); //diagonal

    for(int i=0; i<n; ++i)
    {
        for(int j=0; j<i; ++j)
        {
            T sum = 0;
            for(int k=0; k< t; ++k)
            {
                const T X_ik = X.getData()[i+(n*k)];
                const T X_jk = X.getData()[j+(n*k)];

                sum += pow(X_ik - X_jk, 2) / static_cast<T>(((0.5*(X_ik + X_jk)) + epsilon));
            }

            K[i+(n*j)] = K[j+(n*i)] = sum;
        }
    }

    //  kernel.type = 'chisquared';
    GurlsOptionsList* kernel = new GurlsOptionsList("kernel");

    kernel->addOpt("type", "chisquared");
    kernel->addOpt("K", new OptMatrix<gMat2D<T> >(*K_m));

    return kernel;
}

template<typename T>

static Kernel<T>* gurls::Kernel< T >::factory

(

const std::string &

id

)

throw (BadKernelCreation) [inline, static, inherited]

Warning:

The returned pointer is a plain, un-managed pointer. The calling function is responsible of deallocating the object.

Definition at line 110 of file kernel.h.

    {
        if(id == "linear")
            return new KernelLinear<T>;
        if(id == "rbf")
            return new KernelRBF<T>;
        if(id == "chisquared")
            return new KernelChisquared<T>;

        throw BadKernelCreation(id);
    }

---

The documentation for this class was generated from the following file:

• chisquaredkernel.h