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Algorithm-Classifier-IsolationForest-0.4.0

Changes for version 0.4.0 - 2026-07-03

  • Implement named features and methods for testing single rows using tagged data.
  • The C backend can be built and installed at install time, meaning nothing needs built unless changing the opts. See the docs for more details.
  • new IF_NO_OPENMP=1 selects/builds the serial C backend: no libgomp linkage and no OpenMP runtime in the process at all (unlike OMP_NUM_THREADS=1, which just caps the thread count); IF_NO_OPENMP=0 re-enables OpenMP over a serial install default
  • new IF_RUNTIME_BUILD=1 ignores the prebuilt object and forces the classic runtime build even when the flags match
  • iforest accel updated to reflect various changes to the C backend
  • scoring: the per-leaf path-length adjustment c(size) is now precomputed at tree-pack time and stored in the (previously unused) third slot of packed leaf records, removing a log() call per point per tree from the C scoring hot loop -- about 25% faster axis-mode scoring; results are bit-identical
  • scoring: score_all_xs now picks between two loop shapes based on total forest size: small forests keep the point-major loop (whole forest stays cache-resident anyway), while forests over 4 MB switch to a tree-blocked loop that walks a block of points through one tree at a time so each tree stays hot in L1/L2 instead of being re-streamed from memory per point -- measured ~3.2x faster extended-mode scoring at 400 trees (20k points, 16 features); both shapes add the same terms in the same order, so scores are bit-identical either way
  • any -march (IF_ARCH / IF_NATIVE, configure- or run-time) now automatically adds -ffp-contract=off: with FMA available the compiler otherwise contracts a*b+c into fused multiply-adds whose different rounding silently broke the use_c bit-parity guarantee (one ulp in a split value builds a different tree); the -march win comes from vectorization, so this costs ~nothing
  • scoring: oblique nodes now prefetch both child records before the dot product resolves which branch is taken, hiding the next node's memory latency under the FMA work (~7-10% faster extended-mode scoring on top of the tiling; axis path is untouched -- its single compare has no work to hide a prefetch under); purely a hint, results unchanged

Documentation

Algorithm::Classifier::IsolationForest::BuildFlags

Modules

Algorithm::Classifier::IsolationForest
unsupervised anomaly detection via Isolation Forest or Extended Isolation Forest

Provides

Algorithm::Classifier::IsolationForest::App
in lib/Algorithm/Classifier/IsolationForest/App.pm
Algorithm::Classifier::IsolationForest::App::Command
in lib/Algorithm/Classifier/IsolationForest/App/Command.pm
Algorithm::Classifier::IsolationForest::App::Command::accel
in lib/Algorithm/Classifier/IsolationForest/App/Command/accel.pm
Algorithm::Classifier::IsolationForest::App::Command::bench
in lib/Algorithm/Classifier/IsolationForest/App/Command/bench.pm
Algorithm::Classifier::IsolationForest::App::Command::csv2plot
in lib/Algorithm/Classifier/IsolationForest/App/Command/csv2plot.pm
Algorithm::Classifier::IsolationForest::App::Command::fit
in lib/Algorithm/Classifier/IsolationForest/App/Command/fit.pm
Algorithm::Classifier::IsolationForest::App::Command::gblob
in lib/Algorithm/Classifier/IsolationForest/App/Command/gblob.pm
Algorithm::Classifier::IsolationForest::App::Command::info
in lib/Algorithm/Classifier/IsolationForest/App/Command/info.pm
Algorithm::Classifier::IsolationForest::App::Command::pack
in lib/Algorithm/Classifier/IsolationForest/App/Command/pack.pm
Algorithm::Classifier::IsolationForest::App::Command::predict
in lib/Algorithm/Classifier/IsolationForest/App/Command/predict.pm
Algorithm::Classifier::IsolationForest::PackedData
in lib/Algorithm/Classifier/IsolationForest.pm
BenchAccel
in benchmarking/BenchAccel.pm

Examples

Other files