ml::Features Namespace Reference

Utilities and types for working with features. More...

Typedefs
typedef std::pair< Eigen::Index, double >	IndexedFeatureValue
	Used to sort feature vectors.
template<typename T >
using	VectorRange = std::pair< typename std::vector< T >::iterator, typename std::vector< T >::iterator >
	Pair of vector iterators.

Functions
template<typename T >
VectorRange< T >	from_vector (std::vector< T > &v)
void	set_to_nth (Eigen::Ref< const Eigen::MatrixXd > X, Eigen::Index n, VectorRange< IndexedFeatureValue > features)
	Copies the n-th coordinate to features. More...
void	swap_columns (Eigen::Ref< Eigen::MatrixXd > X, Eigen::Index i1, Eigen::Index i2)
	Swaps two columns in feature matrix. More...
Eigen::Index	partition (Eigen::Ref< Eigen::MatrixXd > X, Eigen::Index pivot_idx, Eigen::Index k)
	Partitions features (in columns) so that those with x[k] < pivot[k] are before the pivot, and those with x[k] > pivot[k] are after it. More...
Eigen::Index	partition (Eigen::Ref< Eigen::MatrixXd > X, Eigen::Ref< Eigen::VectorXd > y, Eigen::Index pivot_idx, Eigen::Index k)
	Partitions features (in columns) and labels so that those with x[k] < pivot[k] are before the pivot, and those with x[k] > pivot[k] are after it. More...

Detailed Description

Utilities and types for working with features.

Function Documentation

from_vector()

template<typename T >

VectorRange<T> ml::Features::from_vector

(

std::vector< T > &

v

)

Creates an iterator pair containing begin() and end().

set_to_nth()

void ml::Features::set_to_nth	(	Eigen::Ref< const Eigen::MatrixXd >	X,
		Eigen::Index	n,
		VectorRange< IndexedFeatureValue >	features
	)

Copies the n-th coordinate to features.

Parameters

[in]	X	Features matrix, with data points in columns.
[in]	n	Coordinate index.
[out]	features	Iterator range for indexed feature values.

Exceptions

std::invalid_argument

If size of the iterator range is different from the number of data points, or n is too large.

swap_columns()

void ml::Features::swap_columns	(	Eigen::Ref< Eigen::MatrixXd >	X,
		Eigen::Index	i1,
		Eigen::Index	i2
	)

Swaps two columns in feature matrix.

Parameters

X	Feature matrix.
i1	Index of the 1st column.
i2	Index of the 2nd column.

Exceptions

std::out_of_range

If i1 >= X.cols() or i2 >= X.cols().

partition() [1/2]

Eigen::Index ml::Features::partition	(	Eigen::Ref< Eigen::MatrixXd >	X,
		Eigen::Index	pivot_idx,
		Eigen::Index	k
	)

Partitions features (in columns) so that those with x[k] < pivot[k] are before the pivot, and those with x[k] > pivot[k] are after it.

pivot = X.col(pivot_idx).

Parameters

X	Features with data points in columns.
pivot_idx	Pivot index.
k	Dimension used for comparison.

Returns

Position of the pivot feature after partitioning.

Exceptions

std::out_of_range

If pivot_idx >= X.cols() or k >= X.rows().

partition() [2/2]

Eigen::Index ml::Features::partition	(	Eigen::Ref< Eigen::MatrixXd >	X,
		Eigen::Ref< Eigen::VectorXd >	y,
		Eigen::Index	pivot_idx,
		Eigen::Index	k
	)

Partitions features (in columns) and labels so that those with x[k] < pivot[k] are before the pivot, and those with x[k] > pivot[k] are after it.

pivot = X.col(pivot_idx).

Parameters

X	Features with data points in columns.
y	Vector of labels.
pivot_idx	Pivot index.
k	Dimension used for comparison.

Returns

Position of the pivot feature after partitioning.

Exceptions

std::out_of_range	If pivot_idx >= X.cols() or k >= X.rows().
std::invalid_argument	If X.cols() != y.size().