General Inverse Degree Calculator

parametric inverse degree family

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About General Inverse Degree Calculator

A general inverse degree calculator computing IDₐ(G) = Σ d(v)^(-a) for any real a. Parametric family: a=1→inverse degree ID, a=2→modified first Zagreb mM₁, a=-1→Σd = 2m. Generalizes multiple inverse-degree type indices. Client-side.

General Inverse Degree Calculator Features

  • IDₐ(G)
  • d^(-a)
  • Any a∈ℝ
  • Parametric
  • Common graphs
General inverse degree IDₐ(G) = Σ d(v)^(-a). Vertex-based parametric family. a=1: ID (inverse degree). a=2: mM₁ (modified Zagreb). a=-1: Σd=2m. a=0: n. Unifies vertex-based degree indices under one parameter.

How to Use

Select graph and exponent:

  • a=1: ID
  • a=2: mM₁
  • Custom: Any a

Special Cases

a=0: n (vertex count). a=-1: Σd = 2m. a=-2: M₁. a=1: ID = Σ1/d. a=2: mM₁ = Σ1/d². Negative a→classical, positive a→inverse. Smooth transition.

Behavior in a

Increasing a: low-degree vertices dominate more. Decreasing a: high-degree dominate. a=0: all equal. The parameter a controls the 'lens' from hub-centric (a<0) to leaf-centric (a>0).

Step-by-Step Instructions

  1. 1Select graph.
  2. 2Choose exponent a.
  3. 3For each vertex: d(v)^(-a).
  4. 4Sum all terms.
  5. 5Explore different a values.

General Inverse Degree Calculator — Frequently Asked Questions

IDₐ vs Rₐ (general Randić)?+

IDₐ is vertex-based: Σ d(v)^(-a). Rₐ is edge-based: Σ (d·d)ᵃ. Different summation domains. IDₐ uses single-vertex degrees, Rₐ uses edge-endpoint products.

Optimal a?+

Depends on target property. a≈1: surface properties. a≈2: peripheral properties. a≈-1: total connectivity. The QSAR-optimal a varies by physico-chemical property.

For regular graphs?+

IDₐ = n·d^(-a) = n/dᵃ. Independent of graph structure beyond degree! Regular graphs collapse the parametric family to a function of d alone.

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