Issues

• Have a different symN__ generator per optimization pass

  cleanupgood first issueoptimization
  stan-dev/stanc3#1736 · Filter by author SteveBronder opened on Sep 29, 2026

• [BUG] Stack overflow

  stan-dev/stanc3#1727 · Filter by author scottdgoddard opened on Sep 22, 2026
  4

• Stan math should have specific type traits only the compiler uses

  cpp-codegenfeatureperformance
  stan-dev/stanc3#1722 · Filter by author SteveBronder opened on Sep 16, 2026
  5

• Add std::move optimization to last use of matrix and array like objects

  featureoptimization
  stan-dev/stanc3#1721 · Filter by author SteveBronder opened on Sep 16, 2026

• Two more loop shapes for vectorize_loops

  optimization
  stan-dev/stanc3#1705 · Filter by author seantalts opened on Sep 10, 2026
  1

• pairwise indexing arrays of varying effects

  feature
  stan-dev/stanc3#1704 · Filter by author bob-carpenter opened on Sep 10, 2026
  1

• Post-2.40: Move loop vectorization to O1

  optimization
  stan-dev/stanc3#1692 · Filter by author WardBrian opened on Sep 3, 2026

• Expose map functions

  featuretypechecker
  stan-dev/stanc3#1680 · Filter by author WardBrian opened on Aug 26, 2026

• Peephole optimization for commonly paired functions

  featurehelp wantedoptimizationperformance
  stan-dev/stanc3#1677 · Filter by author WardBrian opened on Aug 24, 2026

• Function gradient for nested autodiff of user defined functions

  feature
  stan-dev/stanc3#1675 · Filter by author WardBrian opened on Aug 24, 2026
  2

• FR: Allow UDFs to vary only in data annotations

  typechecker
  stan-dev/stanc3#1531 · Filter by author nsiccha opened on Jul 23, 2025
  6

• Flag to disallow functions without higher order derivatives

  featuregood first issuehelp wantedtypechecker
  stan-dev/stanc3#1529 · Filter by author WardBrian opened on Jul 1, 2025
  2

• hook to write transformed data as JSON string

  feature
  stan-dev/stanc3#1522 · Filter by author bob-carpenter opened on Jun 16, 2025
  7

• SoA should allow arbitrary initialization of matrix if it isn't elementwise accessed thereafter

  optimization
  stan-dev/stanc3#1503 · Filter by author WardBrian opened on Mar 13, 2025

• Typechecker: Allow easier modification of standard library

  cleanuptypechecker
  stan-dev/stanc3#1500 · Filter by author WardBrian opened on Mar 10, 2025

• Allowing _lp in the transformed parameters block and jacobian in the model block

  feature
  stan-dev/stanc3#1482 · Filter by author spinkney opened on Dec 18, 2024
  8

• Kronecker Products

  feature
  stan-dev/stanc3#1454 · Filter by author mike-lawrence opened on Oct 10, 2024
  9

• Explore variadic map_rect

  feature
  stan-dev/stanc3#1448 · Filter by author WardBrian opened on Sep 23, 2024
  1

• [FR] Add lower_upper constrain

  featuregood first issue
  stan-dev/stanc3#1438 · Filter by author andrjohns opened on Jul 15, 2024
  5

• [BUG] SoA request is ignored with external c++

  cpp-codegenoptimization
  stan-dev/stanc3#1379 · Filter by author andrjohns opened on Nov 30, 2023
  5

• Typechecker: Allow predicate-based typechecking of library functions

  stan-dev/stanc3#1373 · Filter by author WardBrian opened on Nov 3, 2023
  3

• [FR] Bool data type?

  feature
  stan-dev/stanc3#1328 · Filter by author andrjohns opened on May 11, 2023
  1

• [FR] UDFs taking another UDF as argument

  feature
  stan-dev/stanc3#1325 · Filter by author andrjohns opened on May 8, 2023
  1

• [BUG] Compiler optimizations can prevent bounds checks

  bugcpp-codegenoptimizationrobustness
  stan-dev/stanc3#1295 · Filter by author WardBrian opened on Mar 20, 2023
  3

• SoA optimization can over-promote objects used inside loops to produce slower code

  bugcpp-codegenoptimization
  stan-dev/stanc3#1280 · Filter by author WardBrian opened on Jan 23, 2023