txt: ## dist_zef-antononcube-Math-DistanceFunctions-Native.md
  # Math::DistanceFunctions::Native
  
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  [![](https://img.shields.io/badge/License-Artistic%202.0-0298c3.svg)](https://opensource.org/licenses/Artistic-2.0)
  
  Raku package with distance functions implemented in C.
  Apple's Accelerate library is used if available.
  
  The primary motivation for making this library is to have fast sorting and nearest neighbors computations
  over collections of LLM-embedding vectors.
  
  ---
  
  ## Usage examples
  
  ### Regular vectors
  
  Make a large (largish) collection of large vectors and find Euclidean distances over them:
  
  ```
  use Math::DistanceFunctions::Native;
  
  my @vecs = (^1000).map({ (^1000).map({1.rand}).cache.Array }).Array;
  my @searchVector = (^1000).map({1.rand});
  
  my $start = now;
  my @dists = @vecs.map({ euclidean-distance($_, @searchVector)});
  my $tend = now;
  say "Total time of computing {@vecs.elems} distances: {round($tend - $start, 10 ** -6)} s";
  say "Average time of a single distance computation: {($tend - $start) / @vecs.elems} s";
  
  ```
  
  ```
  # Total time of computing 1000 distances: 0.63326 s
  # Average time of a single distance computation: 0.0006332598499999999 s
  
  ```
  
  ### `CArray` vectors
  
  Use `CArray` vectors instead:
  
  ```
  use NativeCall;
  my @cvecs = @vecs.map({ CArray[num64].new($_) });
  my $cSearchVector = CArray[num64].new(@searchVector);
  
  $start = now;
  my @cdists = @cvecs.map({ euclidean-distance($_, $cSearchVector)});
  $tend = now;
  say "Total time of computing {@cvecs.elems} distances: {round($tend - $start, 10 ** -6)} s";
  say "Average time of a single distance computation: {($tend - $start) / @cvecs.elems} s";
  
  ```
  
  ```
  # Total time of computing 1000 distances: 0.002994 s
  # Average time of a single distance computation: 2.994124e-06 s
  
  ```
  
  I.e., we get ≈ 200 times speed-up using `CArray` vectors and the functions of this package.
  
  ### Edit distance
  
  The loading of this package automatically loads the (C-implemented) function `edit-distance` of
  ["Math::DistanceFunctions::Edit"](https://github.com/antononcube/Raku-Math-DistanceFunctions-Edit).
  Here is an example usage:
  
  ```
  edit-distance('racoon', 'raccoon')
  
  ```
  
  ```
  # 1
  
  ```
  