Implement thread parallelism

CHANGELOG.md

@@ -1,5 +1,25 @@
 # Changelog
 
+## 0.10.0 2026-01-10
+
+### Added
+
+* Rust
+  * Add top-level `interpn`, `interpn_alloc` and `interpn_serial` methods along with supporting enums for selecting methods
+  * Add `par` feature, enabled by default, that enables parallelism with rayon in `interpn` function
+  * Add lazy static for getting number of physical cores to advise thread chunk sizes
+
+### Changed
+
+* Rust
+  * Update deps
+* Python
+  * !Refactor `interpn` function
+    * Combine `check_bounds: bool` and `bounds_check_atol: float` to `check_bounds_with_atol: float | None`
+    * Replace `assume_regular` input with optional `grid_kind` to allow assuming either regular or rectilinear, or making no assumption
+    * Add `max_threads: int | None` input to allow manually limiting parallelism
+    * Use rust top-level `interpn` function as backend for method selection, bounds checks, and parallelism
+
 ## 0.9.1 2025-12-31
 
 ### Changed

Cargo.toml

@@ -1,6 +1,6 @@
 [package]
 name = "interpn"
-version = "0.9.1"
+version = "0.10.0"
 edition = "2024"
 rust-version = "1.87" # 2025-05-15
 authors = ["James Logan <jlogan03@gmail.com>"]
@@ -17,8 +17,12 @@ crate-type = ["cdylib", "rlib"]
 
 [dependencies]
 # Rust lib deps
-num-traits = { version = "0.2.19", default-features = false, features = ["libm"] }
-crunchy = { version = "0.2.4", default-features = false }
+num-traits = { version = "^0.2.19", default-features = false, features = ["libm"] }
+crunchy = { version = "^0.2.4", default-features = false }
+
+# Parallelism
+rayon = { version = "^1.11.0", optional = true }
+num_cpus = { version = "^1.17.0", optional = true }
 
 # Python bindings
 pyo3 = { version = "0.27.2", features = ["extension-module", "abi3-py310", "generate-import-lib"], optional = true }
@@ -27,17 +31,19 @@ numpy = { version = "0.27.1", optional = true }
 # Test-only utils
 itertools = { version = "0.14.0", optional = true }
 
+
 [dev-dependencies]
 rand = "0.9.2"
-criterion = "0.7.0"
+criterion = "0.8.1"
 ndarray = "0.17.1"
 
 [features]
-default = ["std", "crunchy/limit_64"]
+default = ["std", "crunchy/limit_64", "par"]
 python = ["numpy", "pyo3", "std"]
 std = ["itertools"]
 deep-unroll = ["crunchy/limit_256"]
 fma = []
+par = ["std", "rayon", "num_cpus"]
 
 [profile.release]
 opt-level = 3