stan-dev/stan

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Stan development repository. The master branch contains the current release. The develop branch contains the latest stable development. See the Developer Process Wiki for details.

Stars: 2.8k
Forks: 388
Open beginner issues: 0
Indexed issues: 137
Avg merge: 2d 17h
Merged PRs (30d): 15

Dominant language: C++
License: BSD-3-Clause
Last GitHub push: Sep 16, 2026
Latest indexed: Sep 19, 2026
Contributing guide: Contributing guide
Code of conduct: No code of conduct
Beginner labels: good first issue help wanted

Beginner friendly Everything

Open All

137 open issues indexed

Feature request: parallel vb sampling from posterior Open

Difficulty 5/5 Over a week Newbie friendliness 20/100

stan-dev/stan#2796 · Opened Aug 8, 2019
const correctness for services Open

code cleanup

stan-dev/stan#2781 · 1 assignee · Opened Jul 4, 2019
Feature request: low-rank automatic differentiation variational inference Open

Difficulty 5/5 Over a week Newbie friendliness 15/100

stan-dev/stan#2750 · Opened Apr 20, 2019
Request: ADVI delta_ELBO_mean delta_ELBO_med to diagnostic_writer Open

i/o

Difficulty 4/5 3-5 days Newbie friendliness 38/100

stan-dev/stan#2698 · 6 comments · Opened Nov 19, 2018
Rebuild services using config objects with defaults Open

code cleanup i/o interface

stan-dev/stan#2688 · 2 assignees · Opened Nov 7, 2018
remove deep_copy from generated code and parser warnings Open

code cleanup language

stan-dev/stan#2682 · 1 assignee · Opened Oct 25, 2018
Exposing mu to the services (stepsize warmup) Open

algorithm feature good first issue

Difficulty 5/5 Over a week Newbie friendliness 35/100

stan-dev/stan#2670 · 2 comments · Opened Oct 18, 2018
Update `help` option in `runTests.py` Open

Difficulty 1/5 Under an hour Newbie friendliness 65/100

stan-dev/stan#2664 · Opened Oct 11, 2018
Merge Transformed Parameters and Model Blocks Open

feature language

Difficulty 5/5 Over a week Newbie friendliness 25/100

stan-dev/stan#2662 · 1 comment · Opened Oct 10, 2018
gaussian_dlm_obs should allow nonnegative-definite matrices Open

Difficulty 4/5 3-5 days Newbie friendliness 40/100

stan-dev/stan#2658 · 2 comments · Opened Oct 6, 2018
Redesign loggers Open

Difficulty 5/5 Over a week Newbie friendliness 25/100

stan-dev/stan#2579 · 1 comment · Opened Jul 10, 2018
Clean up code: `.str().length()` Open

code cleanup good first issue

stan-dev/stan#2577 · 13 comments · 1 assignee · Opened Jul 10, 2018
Interfacing with 3rd-party PDE libraries Open

Difficulty 5/5 Over a week Newbie friendliness 25/100

stan-dev/stan#2567 · 17 comments · Opened Jul 3, 2018
Expose Quadratic optimizer with linear constraints Open

stan-dev/stan#2556 · 1 assignee · Opened Jun 23, 2018
Consolidate and refactor output from algorithms Open

code cleanup feature i/o interface

stan-dev/stan#2534 · 5 comments · 1 reaction · 1 assignee · Opened Jun 4, 2018
Log density with proportionality in ADVI drops more than constant Open

Difficulty 4/5 3-5 days Newbie friendliness 42/100

stan-dev/stan#2518 · 2 comments · Opened Apr 26, 2018
optimization fails for a constrained parameter Open

Difficulty 4/5 3-5 days Newbie friendliness 25/100

stan-dev/stan#2511 · 6 comments · 1 reaction · Opened Apr 3, 2018
ADVI diagnostic Open

Difficulty 4/5 3-5 days Newbie friendliness 30/100

stan-dev/stan#2474 · 11 comments · Opened Feb 22, 2018
transition method bugged for softabs Open

Difficulty 4/5 3-5 days Newbie friendliness 25/100

stan-dev/stan#2454 · Opened Jan 3, 2018
deprecate int_step Open

bug documentation good first issue

Difficulty 3/5 1-2 days Newbie friendliness 52/100

stan-dev/stan#2433 · 5 comments · Opened Nov 9, 2017
Fix performance test to work on multiple architectures Open

testing

Difficulty 4/5 3-5 days Newbie friendliness 35/100

stan-dev/stan#2429 · 2 comments · Opened Oct 30, 2017
Expose univariate normal operating on sufficient statistics Open

Difficulty 3/5 1-2 days Newbie friendliness 35/100

stan-dev/stan#2394 · Opened Sep 7, 2017
Sampler appears to avoid zero in truncated hierarchical priors Open

Difficulty 4/5 3-5 days Newbie friendliness 25/100

stan-dev/stan#2375 · 7 comments · Opened Aug 4, 2017
Stan should accumulate the mean and variance for all unknowns Open

feature

Difficulty 5/5 Over a week Newbie friendliness 30/100

stan-dev/stan#2361 · 13 comments · Opened Jul 25, 2017
Things needed by interfaces for Stan 3.x Open

feature

stan-dev/stan#2360 · 2 comments · 1 reaction · 3 assignees · Opened Jul 25, 2017
bivariate normal cdf Open

feature good first issue new function

stan-dev/stan#2356 · 15 comments · 2 reactions · 1 assignee · Opened Jul 14, 2017
Add software regression tests Open

testing

Difficulty 5/5 Over a week Newbie friendliness 20/100

stan-dev/stan#2331 · 23 comments · Opened Jun 17, 2017
replace right-bracket space right-bracket with right-bracket right-bracket Open

code cleanup

stan-dev/stan#2297 · 2 assignees · Opened May 1, 2017
ADVI can write 1.#INF on Windows, which cannot be read Open

bug

Difficulty 3/5 1-2 days Newbie friendliness 42/100

stan-dev/stan#2283 · 10 comments · Opened Apr 18, 2017
Warn when step size falls below a given threshold in adaptation? Open

feature

stan-dev/stan#2261 · 2 comments · 1 assignee · Opened Apr 3, 2017
stan::mcmc::ps_point protected methods fast_vector_copy_ and fast_matrix_copy_ should be in own file Open

code cleanup

stan-dev/stan#2253 · 1 assignee · Opened Mar 20, 2017
warnings for unused parameters in I/O Open

feature interface

stan-dev/stan#2239 · 3 comments · 1 assignee · Opened Mar 5, 2017
generate matrix for NNGP Open

Difficulty 4/5 3-5 days Newbie friendliness 25/100

stan-dev/stan#2222 · Opened Feb 2, 2017
floating point values beyond representable range Open

Difficulty 4/5 3-5 days Newbie friendliness 35/100

stan-dev/stan#2208 · Opened Jan 19, 2017
Stan's machine-readable return types (as opposed to its free-form messages) conflict. Open

Difficulty 5/5 Over a week Newbie friendliness 25/100

stan-dev/stan#2198 · 6 comments · Opened Dec 30, 2016
Optimization return code is misleading Open

Difficulty 4/5 3-5 days Newbie friendliness 35/100

stan-dev/stan#2197 · 16 comments · Opened Dec 30, 2016
Things to fix in ADVI Open

code cleanup

Difficulty 4/5 3-5 days Newbie friendliness 35/100

stan-dev/stan#2195 · Opened Dec 29, 2016
Remove step size jittering functionality Open

algorithm code cleanup

stan-dev/stan#2183 · 1 comment · 1 assignee · Opened Dec 22, 2016
Add more tests for higher order autodiff Open

Difficulty 4/5 3-5 days Newbie friendliness 35/100

stan-dev/stan#2142 · 1 comment · Opened Nov 28, 2016
time-based refreshes Open

algorithm feature interface

stan-dev/stan#2070 · 6 comments · 1 assignee · Opened Sep 15, 2016
Confusing warning for low-sample-size runs Open

feature interface

stan-dev/stan#2064 · 2 comments · 1 assignee · Opened Sep 9, 2016
truncation out-of-bounds in model should throw Open

feature language

stan-dev/stan#2053 · 1 assignee · Opened Sep 3, 2016
add poisson_log_lcdf and poisson_log_lccdf functions Open

good first issue new function

stan-dev/stan#2015 · 22 comments · 2 assignees · Opened Aug 16, 2016
Add test for catching sampler issues on a simple, bounded model Open

testing

stan-dev/stan#1987 · 2 assignees · Opened Jul 27, 2016
Bessel function of fractional order Open

feature new function

stan-dev/stan#1939 · 13 comments · 1 assignee · Opened Jun 27, 2016
Optimizing seems to get stuck at boundaries, dependent on seed Open

bug feature

stan-dev/stan#1928 · 3 comments · 1 assignee · Opened Jun 17, 2016
Dense Adaptation Fragile Open

algorithm

stan-dev/stan#1853 · 4 comments · 1 assignee · Opened Apr 10, 2016
clean up sample vs. draw in output and doc Open

code cleanup documentation interface

stan-dev/stan#1801 · 5 comments · 1 assignee · Opened Mar 14, 2016
Generalize auto-tuning in ADVI to grid search function, for auto-tuning in L-BFGS Open

algorithm code cleanup

Difficulty 4/5 3-5 days Newbie friendliness 25/100

stan-dev/stan#1780 · 5 comments · Opened Feb 28, 2016
Rename model_code to program_code, model_name to program_name, etc. Open

stan-dev/stan#1759 · 1 assignee · Opened Jan 29, 2016

stan-dev/stan

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