Peripheral Wiener Index Calculator

boundary vertex distance sum

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About Peripheral Wiener Index Calculator

A peripheral Wiener index calculator computing PW(G) = Σ d(pᵢ,pⱼ) over all peripheral vertex pairs (vertices with ecc = diam). Complements terminal Wiener (leaves). PW focuses on the 'boundary' of the graph. Client-side.

Peripheral Wiener Index Calculator Features

  • PW(G)
  • Peripheral
  • ecc=diam
  • Boundary
  • Common graphs
Peripheral Wiener PW(G) = Σ d(pᵢ,pⱼ) for peripheral vertex pairs (ecc = diam). Only measures distances between the 'boundary' vertices — those at maximum eccentricity. PW captures how spread out the graph's periphery is.

How to Use

Select graph:

  • PW: Peripheral W.
  • ecc=diam: Boundary
  • vs TW: Compare

PW vs TW

Terminal Wiener: distances between leaves (degree-1). Peripheral Wiener: distances between peripheral vertices (max eccentricity). Different concepts! A leaf may not be peripheral. A peripheral vertex may not be a leaf.

Self-Centered Graphs

Self-centered: ALL vertices are peripheral (ecc = diam everywhere). Then PW = W! Examples: K_n, C_n. PW provides maximum information for non-self-centered graphs.

Step-by-Step Instructions

  1. 1Select graph.
  2. 2Find peripheral vertices.
  3. 3Compute pairwise distances.
  4. 4Sum boundary distances.
  5. 5Compare with W.

Peripheral Wiener Index Calculator — Frequently Asked Questions

What are peripheral vertices?+

Vertices with eccentricity = diameter. They're 'as far as possible' from some other vertex. The graph's boundary. In trees: always the leaves of the longest path.

PW vs W?+

W: all pairs. PW: only peripheral-peripheral pairs. PW/W measures 'boundary contribution'. For self-centered graphs: PW = W. For trees: PW often much smaller than W.

When is PW most useful?+

PW characterizes the 'shape of the boundary'. Round molecules: PW small (peripheral atoms close). Linear: PW large (peripheral atoms far). Useful for molecular shape classification.

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