stan-dev / stan-dev/math

Wrapped cauchy density implementation

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feature new function
Dominant language
C++
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Avg merge
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Merged PRs (30d)
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Description

Summary:

Add wrapped cauchy density to Stan math library.

Description:

Implement a wrapped cauchy distribution (a useful distribution in circular statistics) as described in ``An extended family of circular distributions related to wrapped Cauchy distributions via Brownian motion'', S. Kato and M.C. Jones, Bernoulli 19(1), 2013, 154–171. This distribution is characterised by a location parameter -pi()<=mu<=pi(), and a scale parameter 0<=rho<=1, with support from -pi()<=y<=pi().

Current Output:

This function doesn't exist in the Stan math library.

Expected Output:

Five functions: wrapped_cauchy_log, wrapped_cauchy_cdf, wrapped_cauchy_cdf_log, wrapped_cauchy_ccdf_log, wrapped_cauchy_rng.

Current Version:

v2.12.0

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Research direction

The issue names no source files, tests, or entry points. Start by locating existing distribution implementations in the Stan Math Library and consult the cited Kato and Jones paper. Done means providing wrapped_cauchy_log, wrapped_cauchy_cdf, wrapped_cauchy_cdf_log, wrapped_cauchy_ccdf_log, and wrapped_cauchy_rng for the stated parameter and support ranges.

Written by the indexing model from the issue text.

Assessment

Tech stack
cpp
Domain
tooling
Issue type
Feature
Difficulty
5/5
Estimated time
Over a week
Activity status
Stale
Clarity
Mostly clear
Newbie friendliness
25/100

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