RFC: add `proj` for computing the projection of a complex number

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Assessment

Difficulty
5/5
Estimated time
Over a week
Newbie friendliness
25/100
Issue type
Feature
Clarity
Needs clarification
Activity status
Stale
Tech stack
python
Domain
data

Research direction

Start by reviewing the Array API specification and the linked C99 cproj prior art. Resolve whether proj should operate only on complex arrays, then define its behavior and signature clearly enough for the specification to accept the proposal.

Written by the indexing model from the issue text.

Description

API extension Needs Discussion RFC topic: Complex Data Types

This RFC requests to include a new API in the array API specification for the purpose of computing the projection of a complex number on the Riemann sphere.

Overview

The Array API specification currently leaves the model for complex number infinities unspecified, which can be especially problematic when testing for complex number equality. Adding support for proj can help resolve ambiguity by mapping all complex number infinities to a single infinity (i.e., positive real infinity).

Prior art

Proposal:

def proj(x: array, /) -> array

Questions

  • Only operate on complex arrays, similar to conj et al?

cc @kgryte

Dominant language
Python
Stars
281
Forks
52
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