Issues

• [BUG] Resuming a coeval run in a new process needs much more memory than a continuous run

  effort: highpriority: mediumtype: bugtype: performance: memory

  NoFilter by API Breaking: No

  MediumFilter by Priority: Medium

  HighFilter by Effort: High
  Performance: Memory

  21cmfast/21cmFAST#796 · Filter by author DanielaBreitman opened on Oct 1, 2026
  6

  

• OutputStruct.compute() methods don't validate required struct arguments that are None

  context: cache/iocontext: python wrappereffort: lowpriority: medium

  NoFilter by API Breaking: No

  MediumFilter by Priority: Medium

  MediumFilter by Effort: Medium
  21cmfast/21cmFAST#795 · Filter by author steven-murray opened on Oct 1, 2026
  1

  

• [BUG] v4.2 parameter files and output files can't be read: MIN_XE_FOR_FCOLL_IN_TAUX renamed without an alias

  type: bug

  YesFilter by API Breaking: Yes

  HighFilter by Priority: High

  LowFilter by Effort: Low
  Bug

  21cmfast/21cmFAST#793 · Filter by author DanielaBreitman opened on Oct 1, 2026
  5

  

• sigma_z0 is incorrectly called when convert_halo_properties is called

  context: C backendtype: bug

  NoFilter by API Breaking: No

  MediumFilter by Priority: Medium

  MediumFilter by Effort: Medium
  Bug

  21cmfast/21cmFAST#788 · Filter by author jordanflitter opened on Sep 26, 2026
  2

  

• Make sure not to divide by zero in the tests

  type: testing

  NoFilter by API Breaking: No

  LowFilter by Effort: Low
  Tests

  21cmfast/21cmFAST#779 · Filter by author jordanflitter opened on Sep 22, 2026
  

• Mask normal warnings in load_template_file and make more descriptive ones

  context: python wrappertype: testing

  NoFilter by API Breaking: No

  MediumFilter by Effort: Medium
  Tests

  21cmfast/21cmFAST#778 · Filter by author jordanflitter opened on Sep 22, 2026
  

• Define default_inputs_for_mcgs in conftest.py

  type: testing

  NoFilter by API Breaking: No

  LowFilter by Effort: Low
  Tests

  21cmfast/21cmFAST#777 · Filter by author jordanflitter opened on Sep 22, 2026
  

• Inconsistent ionisation_rate_G12 for SOURCE_MODEL="CONST-ION-EFF"

  context: C backendtype: bug

  NoFilter by API Breaking: No

  HighFilter by Priority: High

  MediumFilter by Effort: Medium
  Bug

  21cmfast/21cmFAST#770 · Filter by author jordanflitter opened on Sep 11, 2026
  

• [Question] Using z-photocons instead of no-photocons produces premature end to reionisation

  context: C backendtype: feature: physical
  Feature: Physical

  21cmfast/21cmFAST#766 · Filter by author oliviax727 opened on Sep 7, 2026
  3

  

• [BUG] Memory leak in PF loop

  Bug

  21cmfast/21cmFAST#757 · Filter by author DanielaBreitman opened on Aug 18, 2026

• Peak memory reduction by replacing double with float

  context: C backendtype: performance: memory

  NoFilter by API Breaking: No

  HighFilter by Priority: High

  MediumFilter by Effort: Medium
  Performance: Memory

  21cmfast/21cmFAST#744 · Filter by author jordanflitter opened on Jul 17, 2026
  

• Potential segfaults in C due to exceptions

  context: C backendpriority: mediumtype: bug

  NoFilter by API Breaking: No

  MediumFilter by Priority: Medium

  MediumFilter by Effort: Medium
  Bug

  21cmfast/21cmFAST#742 · Filter by author jordanflitter opened on Jul 15, 2026
  1

  

• Update compute_luminosity_function with stochasticity

  context: python wrappereffort: highpriority: mediumtype: feature: physical

  NoFilter by API Breaking: No

  MediumFilter by Priority: Medium

  HighFilter by Effort: High
  Feature: Physical

  21cmfast/21cmFAST#741 · Filter by author jordanflitter opened on Jul 15, 2026
  

• Support GPU architecture

  effort: highpriority: hightype: maint: buildtype: performance: gputype: performance: speed

  Significant Code ImprovementFilter by Expected Impact: Significant Code Improvement

  HighFilter by Priority: High

  HighFilter by Effort: High
  Performance: GPU

  21cmfast/21cmFAST#728 · Filter by author jordanflitter opened on Jun 16, 2026
  3

  

• Make new module wrappers for cfuncs.py

  context: python wrapperpriority: mediumtype: feature: uitype: maint: documentation

  MediumFilter by Priority: Medium
  21cmfast/21cmFAST#724 · Filter by author jordanflitter opened on Jun 11, 2026
  

• Segfault in test_halo_sampler.py when using ZPRIME_STEP_FACTOR=1.2

  context: C backendpriority: hightype: bugtype: testing
  21cmfast/21cmFAST#723 · Filter by author jordanflitter opened on Jun 11, 2026
  

• Inefficiency for CLI tests

  priority: mediumtype: testing

  MediumFilter by Priority: Medium
  21cmfast/21cmFAST#716 · Filter by author steven-murray opened on Jun 3, 2026
  4

  

• Testing: add flags that fail when warnings are raised

  priority: mediumtype: testing

  MediumFilter by Priority: Medium
  21cmfast/21cmFAST#715 · Filter by author steven-murray opened on Jun 3, 2026
  1

  

• Remove broadcasting inputs to C

  context: C backendcontext: python wrapperpriority: mediumtype: maint: refactoring

  MediumFilter by Priority: Medium
  21cmfast/21cmFAST#707 · Filter by author jordanflitter opened on May 29, 2026
  2

  

• Unexpected large values of HALO_CATALOG_MEM_FACTOR are needed in some scenarios

  context: C backendpriority: hightype: bug
  21cmfast/21cmFAST#692 · Filter by author jordanflitter opened on May 19, 2026
  

• Final memory issues cleanup

  context: C backendcontext: python wrapperpriority: mediumstatus: requires discussionstatus: requires researchtype: maint: documentationtype: performance: memorytype: testing

  Modest Code ImprovementFilter by Expected Impact: Modest Code Improvement

  MediumFilter by Priority: Medium

  HighFilter by Effort: High
  Performance: Memory

  21cmfast/21cmFAST#691 · Filter by author jordanflitter opened on May 18, 2026
  

• Think about best place to initialize arrays

  context: C backendcontext: python wrapperpriority: lowstatus: requires discussiontype: maint: refactoring
  21cmfast/21cmFAST#687 · Filter by author jordanflitter opened on May 5, 2026
  1

  

• Allow to pass global_evolution to C backend

  context: C backendpriority: medium
  21cmfast/21cmFAST#678 · Filter by author jordanflitter opened on Apr 29, 2026
  

• Decide on a consistent mean fixing logic for the emissivity fields

  context: C backendpriority: mediumstatus: requires discussiontype: accuracy

  MediumFilter by Priority: Medium
  21cmfast/21cmFAST#669 · Filter by author jordanflitter opened on Apr 14, 2026
  1

  

• Small redshift step size [BUG]

  context: C backendpriority: mediumtype: bug

  MediumFilter by Priority: Medium
  21cmfast/21cmFAST#667 · Filter by author coltonf96 opened on Apr 13, 2026
  13