topos.functors.probes.mdg.fan

Fan-in / Fan-out Metrics

Counts incoming and outgoing CALLS edges for a file and its symbols.

Mathematical Inspiration:

Fan-in/fan-out is a classic software-engineering measure of module connectivity introduced by Henry & Kafura.

  • Fan-in: how many other symbols call into this file’s symbols. High fan-in means the module is widely depended upon.

  • Fan-out: how many external symbols this file’s symbols call. High fan-out means the module has many dependencies.

The product fan_in * fan_out^2 (the Henry-Kafura complexity) is sometimes used as a structural-risk proxy, but we expose the raw counts so the evaluation section can apply its own thresholds.

class topos.functors.probes.mdg.fan.FanResult(fan_in, fan_out)[source]

Bases: object

Fan-in and fan-out counts for a file.

fan_in

Number of distinct external symbols calling into this file.

Type:

int

fan_out

Number of distinct external symbols called from this file.

Type:

int

fan_in
fan_out
topos.functors.probes.mdg.fan.calculate_fan_in_out(graph, file_node_id, symbol_ids=None)[source]

Calculate fan-in and fan-out for a file node.

Counts distinct external caller/callee symbols connected via CALLS relationships to any symbol contained in the file.

Parameters:

  • graph – The dependency graph.

  • file_node_id – The ID of the file node to analyse.

  • symbol_ids – Pre-computed set of all contained symbol IDs (including file_node_id itself). Computed from the graph when not provided.

Returns:

A FanResult with fan-in and fan-out counts.