`plackett_luce_common`

Shared helpers for grouped Plackett-Luce rankers.

| Availability: | logtalk_load(ranking_protocols(loader))

| Author: Paulo Moura | Version: 1:0:0 | Date: 2026-04-26

| Compilation flags: | static

| Uses: | :ref:`avltree <avltree/0>` | :ref:`list <list/0>`

| Remarks: | (none)

| Inherited public predicates: | (none)

.. contents:: :local: :backlinks: top

Public predicates

(no local declarations; see entity ancestors if any)

Protected predicates

.. index:: index_items/3 .. _plackett_luce_common/0::index_items/3:

index_items/3 ^^^^^^^^^^^^^^^^^

Builds Item-Index pairs for the ordered training items.

| Compilation flags: | static

| Template: | index_items(Items,Index,Indices) | Mode and number of proofs: | index_items(+list,+integer,-list) - one

.. index:: preprocess_groups/10 .. _plackett_luce_common/0::preprocess_groups/10:

preprocess_groups/10 ^^^^^^^^^^^^^^^^^^^^^^^^

Builds per-group choice steps, selection counts, and forward and reverse adjacency dictionaries from grouped rankings under the selected traversal order.

| Compilation flags: | static

| Template: | preprocess_groups(Order,Groups,Dataset,MissingRelevance,IndexDictionary,Count,Steps,SelectionCounts,DirectedAdjacency,ReverseAdjacency) | Mode and number of proofs: | preprocess_groups(+atom,+list,+object_identifier,+atom,+compound,+integer,-list,-list,-compound,-compound) - one

.. index:: selection_exposures/4 .. _plackett_luce_common/0::selection_exposures/4:

selection_exposures/4 ^^^^^^^^^^^^^^^^^^^^^^^^^

Computes the per-item exposure counts implied by the grouped choice steps and the current value dictionary.

| Compilation flags: | static

| Template: | selection_exposures(Steps,SelectionCounts,ValueDictionary,ExposureCounts) | Mode and number of proofs: | selection_exposures(+list,+list,+compound,-list) - one

.. index:: normalize_strengths/6 .. _plackett_luce_common/0::normalize_strengths/6:

normalize_strengths/6 ^^^^^^^^^^^^^^^^^^^^^^^^^

Normalizes raw strength values to sum to one while tracking the maximum absolute change from the current strengths.

| Compilation flags: | static

| Template: | normalize_strengths(RawStrengths,TotalRawStrength,CurrentStrengths,Strengths,MaximumDifference0,MaximumDifference) | Mode and number of proofs: | normalize_strengths(+list(number),+number,+list(number),-list(number),+number,-number) - one

Private predicates

(no local declarations; see entity ancestors if any)

Operators

(none)