stan-dev/stan

deprecate int_step

Open

#2433 opened on Nov 9, 2017

View on GitHub
 (2 comments) (0 reactions) (0 assignees)R (1,476 stars) (270 forks)batch import
bugdocumentationgood first issue

Description

Summary:

int_step(x) and step(x) return different values for 0.

The version of step(x) matches the BUGS definition and the standard definition of the Heaviside step function. Therefore, it should not be changed.

Changing int_step()'s behavior would be confusing, so instead it should be deprecated and replaced with a suggestion to replace existing uses of int_step(n) with the boolean expression (n >= 0), which evaluates to 1 if n >= 0 and 0 otherwise.

Current Version:

v2.17.0

Contributor guide

Tech stack
None
Domain
developer experience
Issue type
refactor
DifficultyEstimated implementation difficulty for a new contributor, from 1 for very small changes to 5 for expert-level work.
2
Estimated timeA rough time range for an experienced contributor to investigate, implement, test, and prepare a pull request.
under 1 hour
Activity statusHow available the issue appears right now: fresh, active, stale, blocked, or waiting on maintainer input.
stale
ClarityHow clearly the issue explains the expected change, acceptance criteria, and next step.
clear
Prerequisites
Stan language basicsDeprecation patterns in C++
Newbie friendlinessA 1-100 score estimating how approachable this issue is for first-time contributors.
70
Research direction
Examine the source code for the step and int step functions, likely in src/stan/math/prim/scal/fun/. Add a deprecation warning to int step and update documentation to suggest using (n >= 0). Ensure consistency with the Heaviside step function definition.