AMReX-Astro/Castro

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Castro (Compressible Astrophysics): An adaptive mesh, astrophysical compressible (radiation-, magneto-) hydrodynamics simulation code for massively parallel CPU and GPU architectures.

Stars: 340
Forks: 105
Open beginner issues: 0
Indexed issues: 130
Avg merge: 3d 8h
Merged PRs (30d): 8

Dominant language: C++
License: No license data
Last GitHub push: Sep 1, 2026
Latest indexed: Sep 20, 2026
Contributing guide: No contributing guide
Code of conduct: Code of conduct
Beginner labels: good first issue help wanted

Beginner friendly Everything

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130 open issues indexed

Hybrid momentum references nonexistent MOL face arrays Open

ai-code-audit sdc

Difficulty 3/5 1-2 days Newbie friendliness 68/100

AMReX-Astro/Castro#3401 · Opened Sep 16, 2026
The stage CFL check repeatedly inspects the unchanged old state Open

ai-code-audit sdc

Difficulty 4/5 3-5 days Newbie friendliness 52/100

AMReX-Astro/Castro#3400 · Opened Sep 16, 2026
Saved SDC fluxes omit the endpoint contribution Open

ai-code-audit sdc

Difficulty 4/5 3-5 days Newbie friendliness 55/100

AMReX-Astro/Castro#3399 · 1 comment · Opened Sep 16, 2026
The SDC4 pressure-work source has only second-order derivatives Open

ai-code-audit sdc

Difficulty 5/5 Over a week Newbie friendliness 42/100

AMReX-Astro/Castro#3398 · 1 comment · Opened Sep 16, 2026
Self-gravity is frozen at the old-time density during SDC sweeps Open

ai-code-audit gravity sdc

Difficulty 5/5 Over a week Newbie friendliness 45/100

AMReX-Astro/Castro#3397 · 1 comment · Opened Sep 16, 2026
SDC2 evaluates time-dependent sources at the end of the step Open

ai-code-audit sdc

Difficulty 4/5 3-5 days Newbie friendliness 64/100

AMReX-Astro/Castro#3395 · Opened Sep 16, 2026
Newton subdivision silently changes the equation being solved Open

ai-code-audit sdc

Difficulty 5/5 Over a week Newbie friendliness 45/100

AMReX-Astro/Castro#3394 · Opened Sep 16, 2026
The VODE-only option does not solve the SDC equation Open

ai-code-audit sdc

Difficulty 4/5 3-5 days Newbie friendliness 48/100

AMReX-Astro/Castro#3393 · Opened Sep 16, 2026
SDC2 conducts heat when diffuse_temp is disabled Open

ai-code-audit sdc

Difficulty 3/5 1-2 days Newbie friendliness 68/100

AMReX-Astro/Castro#3392 · Opened Sep 16, 2026
True SDC ignores castro.do_react Open

ai-code-audit sdc

Difficulty 3/5 1-2 days Newbie friendliness 64/100

AMReX-Astro/Castro#3391 · Opened Sep 16, 2026
True SDC O4 normalizes species before enforcing positive cell-centered density Open

ai-code-audit sdc

Difficulty 4/5 3-5 days Newbie friendliness 48/100

AMReX-Astro/Castro#3385 · Opened Sep 13, 2026
construct_old_react_source() silently overwrites Sburn in the O4 averaged-input path Open

ai-code-audit sdc

Difficulty 4/5 3-5 days Newbie friendliness 52/100

AMReX-Astro/Castro#3384 · Opened Sep 13, 2026
MHD plot variable eint_E includes magnetic energy in the reported internal energy Open

ai-code-audit mhd

Difficulty 4/5 3-5 days Newbie friendliness 48/100

AMReX-Astro/Castro#3380 · Opened Sep 12, 2026
Question About Subcycles Open

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

AMReX-Astro/Castro#3361 · 2 comments · Opened Jul 15, 2026
mhd: prim_half() uses Step 6 intermediate fluxes instead of final Step 9 fluxes in unsplit CTU/CT update Open

ai-code-audit mhd

AMReX-Astro/Castro#3326 · 1 assignee · Opened Mar 24, 2026
new method for temporary FABs Open

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

AMReX-Astro/Castro#3319 · 2 comments · Opened Mar 19, 2026
Modifying the CFL for a custom diffusion term Open

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

AMReX-Astro/Castro#3317 · 1 comment · Opened Mar 16, 2026
Potential indexing/ghost-validity issue: `add_sdc_source_to_states()` reads neighbor cells (`i-1/j-1/k-1`) without local ghost-fill Open

ai-code-audit sdc

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

AMReX-Astro/Castro#3301 · 1 comment · Opened Mar 6, 2026
Not masking in the SCF diagnostic code Open

self-consistent field init

Difficulty 3/5 1-2 days Newbie friendliness 45/100

AMReX-Astro/Castro#3286 · Opened Mar 2, 2026
Point_mass_location Open

gravity

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

AMReX-Astro/Castro#3281 · 4 comments · Opened Mar 2, 2026
SCF diagnostics use stale `phi` scratch data after `multilevel_solve_for_new_phi()` Open

ai-code-audit bug :bug: self-consistent field init

Difficulty 2/5 1-3 hours Newbie friendliness 55/100

AMReX-Astro/Castro#3255 · Opened Feb 24, 2026
`do_hscf_solve()` caches `finest_level` once, but calls `RegridOnly()` inside the iteration loop Open

ai-code-audit bug :bug: self-consistent field init

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

AMReX-Astro/Castro#3254 · 2 comments · Opened Feb 24, 2026
`hse_fill` ignores HSE Newton non-convergence on GPU for implemented boundaries Open

ai-code-audit BCs bug :bug: GPU

Difficulty 4/5 3-5 days Newbie friendliness 45/100

AMReX-Astro/Castro#3252 · Opened Feb 24, 2026
MHD interface reconstruction and HLLD flux path skip auxiliary passives (`QFX/UFX`) Open

ai-code-audit bug :bug: mhd

Difficulty 3/5 1-2 days Newbie friendliness 58/100

AMReX-Astro/Castro#3250 · Opened Feb 24, 2026
MHD utility transforms do not consistently carry `QFX/UFX` auxiliary fields Open

ai-code-audit bug :bug: mhd

Difficulty 3/5 1-2 days Newbie friendliness 68/100

AMReX-Astro/Castro#3249 · Opened Feb 24, 2026
`do_enforce_minimum_density` can divide by zero when rescaling passives Open

ai-code-audit bug :bug: hydro

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

AMReX-Astro/Castro#3248 · 1 comment · Opened Feb 24, 2026
`compute_flux_q` passes total pressure to hybrid momentum flux in radiation mode Open

ai-code-audit bug :bug: radiation

Difficulty 3/5 1-2 days Newbie friendliness 55/100

AMReX-Astro/Castro#3247 · Opened Feb 24, 2026
Stopping criterion reduction initializes with `numeric_limits::min()` instead of `lowest()` Open

ai-code-audit bug :bug:

Difficulty 1/5 Under an hour Newbie friendliness 55/100

AMReX-Astro/Castro#3244 · 2 comments · Opened Feb 24, 2026
`plotFileOutput` uses inconsistent derive filtering and can overrun `plotMF` components Open

ai-code-audit bug :bug: particles

Difficulty 2/5 1-3 hours Newbie friendliness 72/100

AMReX-Astro/Castro#3241 · Opened Feb 24, 2026
`gwstrain` STF projection subtracts only diagonal element instead of full trace Open

ai-code-audit bug :bug: gravity

Difficulty 2/5 1-3 hours Newbie friendliness 78/100

AMReX-Astro/Castro#3237 · 3 comments · Opened Feb 24, 2026
`construct_new_source()` omits `thermo_src` handling for non-MHD while `source_flag()` enables it in SDC Open

ai-code-audit bug :bug:

Difficulty 2/5 1-3 hours Newbie friendliness 55/100

AMReX-Astro/Castro#3236 · Opened Feb 24, 2026
SCF relaxation hardcodes A/B points for z-axis rotation but does not validate `rot_axis` Open

ai-code-audit bug :bug: self-consistent field init

Difficulty 2/5 1-3 hours Newbie friendliness 68/100

AMReX-Astro/Castro#3234 · Opened Feb 24, 2026
Invalid `rot_source_type` is not handled on GPU, leaving rotation energy source uninitialized Open

ai-code-audit bug :bug: rotation

Difficulty 2/5 1-3 hours Newbie friendliness 50/100

AMReX-Astro/Castro#3232 · 1 comment · Opened Feb 24, 2026
`hse_fill` silently skips `+Z` HSE boundary handling on GPU builds Open

ai-code-audit BCs

Difficulty 1/5 Under an hour Newbie friendliness 50/100

AMReX-Astro/Castro#3228 · Opened Feb 24, 2026
`advance_particles` mutates FillPatch density in-place across grown tiles, risking overlap corruption Open

ai-code-audit particles

Difficulty 3/5 1-2 days Newbie friendliness 45/100

AMReX-Astro/Castro#3226 · 1 comment · Opened Feb 24, 2026
`read_particle_params` unconditionally creates `particles::timestamp_dir` even when timestamping is disabled/empty Open

ai-code-audit particles

Difficulty 2/5 1-3 hours Newbie friendliness 65/100

AMReX-Astro/Castro#3225 · Opened Feb 24, 2026
`define_new_center` can divide by zero when parabola fit curvature is zero Open

ai-code-audit gravity

Difficulty 2/5 1-3 hours Newbie friendliness 55/100

AMReX-Astro/Castro#3219 · 1 comment · Opened Feb 24, 2026
`riemann_solvers.H`: multigroup radiation state storage overwrites `QRAD` instead of writing `QRAD+g` Open

ai-code-audit radiation

Difficulty 1/5 Under an hour Newbie friendliness 48/100

AMReX-Astro/Castro#3215 · 1 comment · Opened Feb 24, 2026
`Radiation::filBndry` periodic path only fills one component, breaking multigroup boundary data Open

ai-code-audit radiation

Difficulty 2/5 1-3 hours Newbie friendliness 68/100

AMReX-Astro/Castro#3210 · Opened Feb 24, 2026
RadSolve::levelFluxFaceToCenter uses wrong neighbor metric indexing and wrong denominator for `idim==1` Open

ai-code-audit radiation

Difficulty 2/5 1-3 hours Newbie friendliness 45/100

AMReX-Astro/Castro#3208 · 1 comment · Opened Feb 24, 2026
do we need clean_state in both initialize_advance and initialize_do_advance? Open

clean-up performance

Difficulty 3/5 1-2 days Newbie friendliness 45/100

AMReX-Astro/Castro#3180 · Opened Dec 12, 2025
Documentation for radiation in Castro Open

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

AMReX-Astro/Castro#3156 · Opened Oct 14, 2025
Diffusion of species concentration in Castro Open

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

AMReX-Astro/Castro#3132 · 1 comment · Opened Sep 3, 2025
consider bumping language standard to C++20 Open

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

AMReX-Astro/Castro#3096 · 1 comment · Opened Jun 30, 2025
simplified-SDC w/o burning just needs a single iteration Open

performance reactions sdc

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

AMReX-Astro/Castro#3077 · Opened May 20, 2025
User-defined auxiliary variable does not evolve as expected Open

Difficulty 4/5 3-5 days Newbie friendliness 45/100

AMReX-Astro/Castro#3051 · 2 comments · Opened Mar 28, 2025
update yt frontend for exotically named nuclei Open

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

AMReX-Astro/Castro#3032 · 1 comment · Opened Feb 10, 2025
`simple_convection` problem encounters negative density with SDC 4th order Open

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

AMReX-Astro/Castro#3029 · Opened Jan 31, 2025
sponge is not implemented for true SDC Open

sdc

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

AMReX-Astro/Castro#3017 · 1 comment · Opened Jan 8, 2025
experiment with AMReX WorkEstType Open

help wanted

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

AMReX-Astro/Castro#3009 · Opened Dec 8, 2024

AMReX-Astro/Castro

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