• Stroud - Coeficient for computing the time required to program.

Computes Halstead complexity numbers for an entity.

Author: Paulo Moura
Version: 0.7
Date: 2018/7/18
Compilation flags:
static, context_switching_calls

Public interface

(see related entities)

Protected interface

(see related entities)

Private predicates

(see related entities)




  • Definition of operators: Predicates declared, user-defined, and called are interpreted as operators. Built-in predicates and built-in control constructs are ignored.
  • Definition of operands: Predicate arguments are abstracted and interpreted as operands. Note that this definition of operands is a significant deviation from the original definition, which used syntactic literals.
  • Pn: Number of distinct predicates (declared, defined, called, or updated)
  • PAn: Number of predicate arguments (assumed distinct)
  • Cn: Number of predicate calls/updates + number of clauses
  • CAn: Number of predicate call/update arguments + number of clause head arguments
  • EV: Entity vocabulary: EV = Pn + PAn
  • EL: Entity length: EL = Cn + CAn
  • V: Volume: V = EL * log2(EV)
  • D: Difficulty: D = (Pn/2) * (CAn/An)
  • E: Effort: E = D * V
  • T: Time required to program: T = E/k seconds (k is the Stroud number; defaults to 18)
  • B: Number of delivered bugs: B = V/3000
  • Entity score: Represented as the compound term pn_pan_cn_can_ev_el_v_d_e_t_b/11.