Perf #7: Investigate Dict{Int, Any} type stability in KKT construction#157
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hmzh-khn wants to merge 4 commits into
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Perf #7: Investigate Dict{Int, Any} type stability in KKT construction#157hmzh-khn wants to merge 4 commits into
hmzh-khn wants to merge 4 commits into
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Tests verify that:
- Hot-path containers (K_evals, M_evals, N_evals, M_buffers, N_buffers)
use concrete value types for type-stable access during Newton iterations
- Cold-path dicts (πs, Ms, Ns, Ks) intentionally use Dict{Int, Any}
for heterogeneous symbolic types (BlockVector vs Vector{Num})
- π_sizes_trimmed is Dict{Int, Int} (not Any)
- Pre-allocated k_eval_buffers are reused (identity check)
- End-to-end solve produces correct results with all typed containers
These tests protect against regressions if someone "improves" the cold-path
dicts or accidentally introduces Any-typed containers on the hot path.
Co-Authored-By: Claude Opus 4.6 <[email protected]>
- Add explicit type annotation on π_sizes_trimmed in preoptimize_nonlinear_solver
for self-documentation (Julia already inferred this correctly)
- Register test_typed_kkt_dicts.jl in slow test tier
- Update test_test_tiers.jl expected file lists
Investigation finding: All Dict{Int, Any} instances in qp_kkt.jl (lines 92-95)
and nonlinear_kkt.jl (line 256) are COLD PATH only — used during one-time
symbolic construction, never accessed in the Newton iteration loop. The hot-path
containers (K_evals, M_evals, M_buffers, etc.) already use concrete types
(Vector{Union{Matrix{Float64}, Nothing}}, Dict{Int, Matrix{Float64}}).
Co-Authored-By: Claude Opus 4.6 <[email protected]>
Benchmarks verify that hot-path dict access (Dict{Int, Matrix{Float64}})
is not a bottleneck. Includes micro-benchmark comparing typed vs untyped
dict access, and full solve / compute_K_evals benchmarks.
Co-Authored-By: Claude Opus 4.6 <[email protected]>
Key finding: All Dict{Int, Any} in KKT construction are cold-path only.
Hot-path containers were already well-typed from previous PRs.
Co-Authored-By: Claude Opus 4.6 <[email protected]>
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Summary
Investigation PR for Dict{Int, Any} type instability in KKT construction (
qp_kkt.jllines 92-95,nonlinear_kkt.jlline 256).Key finding: All
Dict{Int, Any}instances are COLD PATH only. They are used during one-time symbolic construction and never accessed in the Newton iteration loop. The hot-path containers were already correctly typed from previous PRs (Perf #4-6):Vector{Union{Matrix{Float64}, Nothing}}for K/M/N evalsDict{Int, Matrix{Float64}}for M/N buffersVector{MNFunctionWrapper}for compiled M/N functionsVector{Int}for π_sizesChanges
src/nonlinear_kkt.jl: Add explicitDict{Int, Int}type annotation onπ_sizes_trimmed(self-documenting, Julia already inferred correctly)test/test_typed_kkt_dicts.jl: 24 new regression tests documenting hot-path vs cold-path type guaranteestest/test_tiers.jl: Register new test in slow tiertest/test_test_tiers.jl: Update expected file listsscripts/benchmark_typed_kkt_dicts.jl: Benchmark script for typed dict accessRETROSPECTIVES.md: PR retrospectiveTesting
julia --project=. -e 'using Pkg; Pkg.test()')Investigation Details
Call chain trace:
solve()→run_nonlinear_solver()→compute_K_evals()(hot path)πsDict{Int, Any}MsDict{Int, Any}NsDict{Int, Any}KsDict{Int, Any}π_sizes_trimmedDict{Int, Int}M_buffersN_buffersK_evalsChangelog
🤖 Generated with Claude Code