An example kernel function. More...
Public Member Functions | |
| ExampleKernel () | |
| The default constructor, which takes no parameters. More... | |
template < typename Archive > | |
| void | serialize (Archive &, const uint32_t) |
| Serializes the kernel. More... | |
Static Public Member Functions | |
template < typename VecTypeA , typename VecTypeB > | |
| static double | ConvolutionIntegral (const VecTypeA &, const VecTypeB &) |
| Obtains the convolution integral [integral K(||x-a||)K(||b-x||)dx] for the two vectors. More... | |
template < typename VecTypeA , typename VecTypeB > | |
| static double | Evaluate (const VecTypeA &, const VecTypeB &) |
| Evaluates the kernel function for two given vectors. More... | |
| static double | Normalizer () |
| Obtains the normalizing volume for the kernel with dimension $dimension$. More... | |
Detailed Description
An example kernel function.
This is not a useful kernel, but it implements the two functions necessary to satisfy the Kernel policy (so that a class can be used whenever an mlpack method calls for a typename Kernel template parameter.
All that is necessary is a constructor and an Evaluate() function. More methods could be added; for instance, one useful idea is a constructor which takes parameters for a kernel (for instance, the width of the Gaussian for a Gaussian kernel). However, mlpack methods cannot count on these various constructors existing, which is why most methods allow passing an already-instantiated kernel object (and by default the method will construct the kernel with the default constructor). So, for instance,
will set up kernel PCA using a Gaussian kernel with a width of 5.0, but
will create the kernel with the default constructor. It is important (but not strictly mandatory) that your default constructor still gives a working kernel.
- Note
- Not all kernels require state. For instance, the regular dot product needs no parameters. In that case, no local variables are necessary and
Evaluate()can (and should) be declared static. However, for greater generalization, mlpack methods expect all kernels to require state and hence must store instantiated kernel functions; this is why a default constructor is necessary.
Definition at line 76 of file example_kernel.hpp.
Constructor & Destructor Documentation
◆ ExampleKernel()
|
inline |
The default constructor, which takes no parameters.
Because our simple example kernel has no internal parameters that need to be stored, the constructor does not need to do anything. For a more complex example, see the GaussianKernel, which stores an internal parameter.
Definition at line 85 of file example_kernel.hpp.
Member Function Documentation
◆ ConvolutionIntegral()
|
inlinestatic |
Obtains the convolution integral [integral K(||x-a||)K(||b-x||)dx] for the two vectors.
In this case, because our simple example kernel has no internal parameters, we can declare the function static. For a more complex example which cannot be declared static, see the GaussianKernel, which stores an internal parameter.
- Template Parameters
-
VecTypeA Type of first vector (arma::vec, arma::sp_vec should be expected). VecTypeB Type of second vector (arma::vec, arma::sp_vec).
- Parameters
-
* (a) First vector. * (b) Second vector.
- Returns
- the convolution integral value.
Definition at line 126 of file example_kernel.hpp.
◆ Evaluate()
|
inlinestatic |
Evaluates the kernel function for two given vectors.
In this case, because our simple example kernel has no internal parameters, we can declare the function static. For a more complex example which cannot be declared static, see the GaussianKernel, which stores an internal parameter.
- Template Parameters
-
VecTypeA Type of first vector (arma::vec, arma::sp_vec should be expected). VecTypeB Type of second vector (arma::vec, arma::sp_vec).
- Parameters
-
* (a) First vector. * (b) Second vector.
- Returns
- K(a, b).
Definition at line 101 of file example_kernel.hpp.
◆ Normalizer()
|
inlinestatic |
Obtains the normalizing volume for the kernel with dimension $dimension$.
In this case, because our simple example kernel has no internal parameters, we can declare the function static. For a more complex example which cannot be declared static, see the GaussianKernel, which stores an internal parameter.
- Returns
- the normalization constant.
Definition at line 138 of file example_kernel.hpp.
◆ serialize()
|
inline |
Serializes the kernel.
In this case, the kernel has no members, so we do not need to do anything at all.
Definition at line 109 of file example_kernel.hpp.
The documentation for this class was generated from the following file:
- /home/ryan/src/mlpack.org/_src/mlpack-git/src/mlpack/core/kernels/example_kernel.hpp