Native stride_align API surface, grouped by what you're doing.
Most pages share the same shape: a small "output-processing
variants" table that explains the suffix family
(_scores / _normalized_scores / _best / _top_k) once, then
an algorithm list with one paragraph each.
Native API (primary)
| Page | Covers |
|---|---|
| edit-distance | Levenshtein, Damerau-Levenshtein (OSA + unrestricted), Indel, Hamming |
| similarity | Jaro, Jaro-Winkler, n-gram (Jaccard / Dice / cosine / overlap), Ratcliff-Obershelp, Monge-Elkan |
| alignment | Smith-Waterman, Needleman-Wunsch, Farrar score-only, traceback, CIGAR |
| cdist | All-pairs cdist, cdist_above_threshold, cdist_top_k, cdist_top_k_per_query, Scorer enum, pruning |
| matrices | SubstitutionMatrix, built-in BLOSUM and PAM, NCBI text loader |
| dtw | Dynamic Time Warping with Sakoe-Chiba band and alternative local metrics |
| phonetic | Soundex, Metaphone, Double Metaphone, NYSIIS, MRA, Caverphone 2, Cologne Phonetic, Daitch-Mokotoff, Beider-Morse |
Compatibility shims (migration aids)
| Page | Covers |
|---|---|
| rapidfuzz-shim | stride_align.rapidfuzz.{fuzz, distance, process, utils} — drop-in replacement for rapidfuzz. |
| thefuzz-shim | stride_align.thefuzz.{fuzz, process, utils} — work-alike for TheFuzz 0.22.1's integer scorers and extraction API. |
| parasail-shim | stride_align.parasail — drop-in replacement for parasail-python (Smith-Waterman / Needleman-Wunsch / semi-global, BLOSUM/PAM, Result / Cigar / Traceback). |
| jellyfish-shim | stride_align.jellyfish — work-alike for Jellyfish's edit, similarity, and phonetic functions. |
These shims are migration aids; new code should call the native API directly.
Two dimensions
The API has two orthogonal dimensions: which algorithm and what shape you want the output in. Rather than enumerating every (algorithm × shape) combination, each page documents the shape suffixes once at the top and then lists the algorithms. Common output suffixes:
| Suffix | Returns |
|---|---|
_score(query, target) |
single int / float |
_normalized_score(query, target) |
single float in [0, 1] |
_scores(query, targets) |
ndarray of int / float, one per target |
_normalized_scores(query, targets) |
ndarray[float64] in [0, 1], one per target |
_best(query, targets) |
(target, score) or None |
_normalized_best(query, targets) |
(target, normalised_score) or None |
_top_k(query, targets, k=…) |
list of top-k (target, score) |
cdist* family |
full grid / threshold / top-k over many queries × many targets |
Alignment and DTW have a richer variant family because they return paths, CIGARs, and per-target traceback — see alignment.
Cross-cutting
- Inputs: every kernel accepts
bytes,str(UCS-1 / UCS-2 / UCS-4 — zero-copy, no.encode("utf-8")round-trip), and NumPy integerndarray. UCS-2 inputs go straight into a 16-bit-token SIMD path so Chinese / Japanese / Korean strings use the same kernel as ASCII rather than being downcoded to bytes. - GIL: every SIMD kernel releases the GIL while running. The
cdist family parallelises rows across
cpu_countworker threads. - Backend dispatch: the widest SIMD kernel for the current CPU is chosen once at import. See edit-distance#simd-dispatch for the priority order.
- Cutoff push-down: edit-distance entry points accept
score_cutoff=kand bail per lane when the lower bound on distance exceedsk— saves work over full DP + filter.
See also
- ../../README — project overview, install, quick start
- ../../BENCHMARK — performance numbers vs parasail, rapidfuzz, python-Levenshtein, editdistance
- ../../CHANGELOG — version history
- ../adding-a-new-algorithm — internals if you want to add a new SIMD-backed kernel