Issues

Data races on shared expressions: lazy hash_value() and is_positive()/infer_assumptions mutate nodes from const read paths (TSan-confirmed)

NumSim-Stack/numsim-cas#504 · opened

on Sep 19, 2026

Public simplify() entry point: re-run folds and opt-in passes on a finished expression

NumSim-Stack/numsim-cas#501 · opened

on Sep 19, 2026

Named intermediates for tensor and t2s expressions (only scalar_named_expression exists)

NumSim-Stack/numsim-cas#499 · opened

on Sep 19, 2026

Printers truncate doubles to 6 significant digits; no precision control (breaks value-preserving round trips)

NumSim-Stack/numsim-cas#500 · opened

on Sep 19, 2026

1

Expression introspection API: free_symbols, metrics, for_each_node, printable assumptions

NumSim-Stack/numsim-cas#498 · opened

on Sep 19, 2026

Isotropic functions do not propagate definiteness: sqrt(PD), exp(sym) not tagged PD

NumSim-Stack/numsim-cas#496 · opened

on Sep 19, 2026

t2s comparisons, max/min and Macaulay bracket are missing — J2 return mapping not expressible

NumSim-Stack/numsim-cas#497 · opened

on Sep 19, 2026

Kinematics folds: A:I{4} → A and one spelling of F⁻ᵀ (inv(trans) vs trans(inv))

NumSim-Stack/numsim-cas#494 · opened

on Sep 19, 2026

Invariant folds miss t2s-scaled tensors: det(J^(-1/3) F) never simplifies to 1 (isochoric split)

NumSim-Stack/numsim-cas#495 · opened

on Sep 19, 2026

Derivatives w.r.t. symmetric tensors: fold P_sym contractions to sym()/dev() and tag results Symmetric / MinorMajor

NumSim-Stack/numsim-cas#493 · opened

on Sep 19, 2026

Invalid expression_holder is rejected by get()/operators but silently accepted by evaluators (returns 0), diff and to_string

NumSim-Stack/numsim-cas#492 · opened

on Sep 19, 2026

Inferred assumptions are cached forever: adding or erasing a leaf assumption after the first query leaves compounds stale (stale-true lets abs fold unsoundly)

NumSim-Stack/numsim-cas#491 · opened

on Sep 19, 2026

Contradictory assumptions are accepted silently: x positive AND negative makes abs(x)→x and sign(x)→1 both fire

NumSim-Stack/numsim-cas#490 · opened

on Sep 19, 2026

Parser rejects exponent-notation literals the printer emits (1e-07*x, 2.5e+10) — breaks parse(to_string(e))

NumSim-Stack/numsim-cas#489 · opened

on Sep 19, 2026

solve(): quadratic returns NaN 'solutions' for a negative discriminant, uses the cancellation-prone root formula, and cannot distinguish 'no solution' from 'unsupported'

NumSim-Stack/numsim-cas#488 · opened

on Sep 19, 2026

1

asinh(x) evaluates to -inf for large negative x (cancellation in log(x + sqrt(x²+1))); derivative NaN

NumSim-Stack/numsim-cas#487 · opened

on Sep 19, 2026

1

API surface: header-only claim is false, three contraction vocabularies, three assumption spellings, dead space tags

NumSim-Stack/numsim-cas#486 · opened

on Sep 19, 2026

Test oracle is the printed string (706 vs 354 numeric): it pins the hash function, not the mathematics

NumSim-Stack/numsim-cas#485 · opened

on Sep 19, 2026

Error policy: user-reachable asserts, std:: exceptions outside cas_error, and blurred error classes

NumSim-Stack/numsim-cas#483 · opened

on Sep 19, 2026

Adding a node costs 13–21 files and rebuild-visitor omissions are silent — generate a node×visitor coverage test

NumSim-Stack/numsim-cas#484 · opened

on Sep 19, 2026

Canonical form depends on annotation time: folds run at construction, assumptions are written afterwards

NumSim-Stack/numsim-cas#482 · opened

on Sep 19, 2026

t2s tanh derivative returns a finite wrong value for large arguments (overflow collapses one term)

NumSim-Stack/numsim-cas#480 · opened

on Sep 18, 2026

permute_indices_wrapper ctor does not validate index count against rank (factory does)

NumSim-Stack/numsim-cas#476 · opened

on Sep 17, 2026

pow(sqrt(x), n) with odd n is sound for all real x but blocked by the #462 gate

NumSim-Stack/numsim-cas#475 · opened

on Sep 17, 2026

substitute/rebuild/differentiation re-traverse shared nodes and flatten sharing — needs a node→holder cache

NumSim-Stack/numsim-cas#472 · opened

on Sep 17, 2026

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Issues

Data races on shared expressions: lazy hash_value() and is_positive()/infer_assumptions mutate nodes from const read paths (TSan-confirmed)

Public simplify() entry point: re-run folds and opt-in passes on a finished expression

Named intermediates for tensor and t2s expressions (only scalar_named_expression exists)

Printers truncate doubles to 6 significant digits; no precision control (breaks value-preserving round trips)

Expression introspection API: free_symbols, metrics, for_each_node, printable assumptions

Isotropic functions do not propagate definiteness: sqrt(PD), exp(sym) not tagged PD

t2s comparisons, max/min and Macaulay bracket are missing — J2 return mapping not expressible

Kinematics folds: A:I{4} → A and one spelling of F⁻ᵀ (inv(trans) vs trans(inv))

Invariant folds miss t2s-scaled tensors: det(J^(-1/3) F) never simplifies to 1 (isochoric split)

Derivatives w.r.t. symmetric tensors: fold P_sym contractions to sym()/dev() and tag results Symmetric / MinorMajor

Invalid expression_holder is rejected by get()/operators but silently accepted by evaluators (returns 0), diff and to_string

Inferred assumptions are cached forever: adding or erasing a leaf assumption after the first query leaves compounds stale (stale-true lets abs fold unsoundly)

Contradictory assumptions are accepted silently: x positive AND negative makes abs(x)→x and sign(x)→1 both fire

Parser rejects exponent-notation literals the printer emits (1e-07*x, 2.5e+10) — breaks parse(to_string(e))

solve(): quadratic returns NaN 'solutions' for a negative discriminant, uses the cancellation-prone root formula, and cannot distinguish 'no solution' from 'unsupported'

asinh(x) evaluates to -inf for large negative x (cancellation in log(x + sqrt(x²+1))); derivative NaN

API surface: header-only claim is false, three contraction vocabularies, three assumption spellings, dead space tags

Test oracle is the printed string (706 vs 354 numeric): it pins the hash function, not the mathematics

Error policy: user-reachable asserts, std:: exceptions outside cas_error, and blurred error classes

Adding a node costs 13–21 files and rebuild-visitor omissions are silent — generate a node×visitor coverage test

Canonical form depends on annotation time: folds run at construction, assumptions are written afterwards

t2s tanh derivative returns a finite wrong value for large arguments (overflow collapses one term)

permute_indices_wrapper ctor does not validate index count against rank (factory does)

pow(sqrt(x), n) with odd n is sound for all real x but blocked by the #462 gate

substitute/rebuild/differentiation re-traverse shared nodes and flatten sharing — needs a node→holder cache