Visitor that accumulates per-variable contributions for VI2 and VI3. More...

#include <VIVisitor.hpp>

Public Member Functions
	VIVisitor (int n_vars, types::FeatureVector const *scale=nullptr)
	Construct a visitor for a tree with `n_vars` variables.

void	visit (TreeCondition const &node) override
	Visit a split node; accumulate contributions and recurse.

void	visit (TreeResponse const &) override
	Visit a leaf node; no contribution to VI.

Public Attributes
types::FeatureVector const *	scale = nullptr
	Optional per-variable σ vector (size p); scale[j] = σ_j.

std::vector< types::Feature >	vi2_contributions
	VI2 contributions per variable (size p).

std::vector< types::Feature >	vi3_contributions
	VI3 contributions per variable (size p).

Detailed Description

Visitor that accumulates per-variable contributions for VI2 and VI3.

Traverses a single tree and, at each split node s with G_s groups and PP index I_s, accumulates:

vi2_contributions[j] += |a_j| / G_s vi3_contributions[j] += I_s * |a_j|

When scale is provided, each |a_j| is multiplied by σ_j so that coefficients are comparable across variables with different units.

The caller is responsible for forest-level aggregation and normalization described in Da Silva et al. (2021).

Constructor & Destructor Documentation

◆ VIVisitor()

ppforest2::VIVisitor::VIVisitor	(	int	n_vars,
		types::FeatureVector const *	scale = nullptr )

inlineexplicit

Construct a visitor for a tree with n_vars variables.

Parameters

n_vars	Number of predictor variables (p).
scale	Optional per-variable σ vector (size p).

Member Function Documentation

◆ visit() [1/2]

void ppforest2::VIVisitor::visit ( TreeCondition const & node )

inlineoverridevirtual

Visit a split node; accumulate contributions and recurse.

Parameters

node	Split node with projector and pp_index_value.

Implements ppforest2::TreeNode::Visitor.

◆ visit() [2/2]

void ppforest2::VIVisitor::visit ( TreeResponse const & )

inlineoverridevirtual

Visit a leaf node; no contribution to VI.

Leaf nodes hold only a class label and do not contribute to variable importance.

Implements ppforest2::TreeNode::Visitor.

Member Data Documentation

◆ scale

types::FeatureVector const* ppforest2::VIVisitor::scale = nullptr

Optional per-variable σ vector (size p); scale[j] = σ_j.

◆ vi2_contributions

std::vector<types::Feature> ppforest2::VIVisitor::vi2_contributions

VI2 contributions per variable (size p).

◆ vi3_contributions

std::vector<types::Feature> ppforest2::VIVisitor::vi3_contributions

VI3 contributions per variable (size p).

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

core/src/models/VIVisitor.hpp

Public Member Functions

Public Attributes