Fix speed of "song to song" sorting method

.github/workflows/rust.yml

@@ -23,7 +23,7 @@ jobs:
         toolchain: nightly-2021-04-01
         override: false
     - name: Packages
-      run: sudo apt-get install build-essential yasm libavutil-dev libavcodec-dev libavformat-dev libavfilter-dev libavfilter-dev libavdevice-dev libswresample-dev libfftw3-dev ffmpeg
+      run: sudo apt-get update && sudo apt-get install build-essential yasm libavutil-dev libavcodec-dev libavformat-dev libavfilter-dev libavfilter-dev libavdevice-dev libswresample-dev libfftw3-dev ffmpeg
     - name: Build
       run: cargo build --verbose
     - name: Run tests

CHANGELOG.md

@@ -1,5 +1,10 @@
 # Changelog
 
+## bliss 0.4.0
+* Make the song-to-song custom sorting method faster.
+* Rename `to_vec` and `to_arr1` to `as_vec` and `as_arr1` .
+* Add a playlist_dedup function. 
+
 ## bliss 0.3.5
 * Add custom sorting methods for playlist-making.
 

Cargo.lock

@@ -882,9 +882,9 @@ dependencies = [
 
 [[package]]
 name = "rand"
-version = "0.8.3"
+version = "0.8.4"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "0ef9e7e66b4468674bfcb0c81af8b7fa0bb154fa9f28eb840da5c447baeb8d7e"
+checksum = "2e7573632e6454cf6b99d7aac4ccca54be06da05aca2ef7423d22d27d4d4bcd8"
 dependencies = [
  "libc",
  "rand_chacha",

src/distance.rs

@@ -12,6 +12,7 @@ use crate::Library;
 use crate::Song;
 use crate::NUMBER_FEATURES;
 use ndarray::{Array, Array1};
+use ndarray_stats::QuantileExt;
 use noisy_float::prelude::*;
 
 /// Convenience trait for user-defined distance metrics.
@@ -39,34 +40,35 @@ pub fn cosine_distance(a: &Array1<f32>, b: &Array1<f32>) -> f32 {
 }
 
 /// Sort `songs` in place by putting songs close to `first_song` first
-/// using the `distance` metric. Deduplicate identical songs.
+/// using the `distance` metric.
 pub fn closest_to_first_song(
     first_song: &Song,
     songs: &mut Vec<Song>,
     distance: impl DistanceMetric,
 ) {
     songs.sort_by_cached_key(|song| n32(first_song.custom_distance(song, &distance)));
-    songs.dedup_by_key(|song| n32(first_song.custom_distance(song, &distance)));
 }
 
 /// Sort `songs` in place using the `distance` metric and ordering by
-/// the smallest distance between each song. Deduplicate identical songs.
+/// the smallest distance between each song.
 ///
 /// If the generated playlist is `[song1, song2, song3, song4]`, it means
 /// song2 is closest to song1, song3 is closest to song2, and song4 is closest
 /// to song3.
+///
+/// Note that this has a tendency to go from one style to the other very fast,
+/// and it can be slow on big libraries.
 pub fn song_to_song(first_song: &Song, songs: &mut Vec<Song>, distance: impl DistanceMetric) {
-    let mut new_songs = vec![first_song.to_owned()];
+    let mut new_songs = Vec::with_capacity(songs.len());
     let mut song = first_song.to_owned();
-    loop {
-        if songs.is_empty() {
-            break;
-        }
-        songs 
-            .retain(|s| n32(song.custom_distance(s, &distance)) != 0.);
-        songs.sort_by_key(|s| n32(song.custom_distance(s, &distance)));
-        song = songs.remove(0);
+
+    while !songs.is_empty() {
+        let distances: Array1<f32> =
+            Array::from_shape_fn(songs.len(), |i| song.custom_distance(&songs[i], &distance));
+        let idx = distances.argmin().unwrap();
+        song = songs[idx].to_owned();
         new_songs.push(song.to_owned());
+        songs.retain(|s| s != &song);
     }
     *songs = new_songs;
 }
@@ -126,7 +128,13 @@ mod test {
         song_to_song(&first_song, &mut songs, euclidean_distance);
         assert_eq!(
             songs,
-            vec![first_song, second_song, third_song, fourth_song],
+            vec![
+                first_song,
+                first_song_dupe.to_owned(),
+                second_song,
+                third_song,
+                fourth_song
+            ],
         );
     }
 
@@ -187,7 +195,14 @@ mod test {
         closest_to_first_song(&first_song, &mut songs, euclidean_distance);
         assert_eq!(
             songs,
-            vec![first_song, second_song, fourth_song, third_song],
+            vec![
+                first_song,
+                first_song_dupe,
+                second_song,
+                fourth_song,
+                fifth_song,
+                third_song
+            ],
         );
     }
 

src/library.rs

@@ -5,7 +5,7 @@
 //! MPD](https://github.com/Polochon-street/blissify-rs) could also be useful.
 #[cfg(doc)]
 use crate::distance;
-use crate::distance::{closest_to_first_song, DistanceMetric, euclidean_distance};
+use crate::distance::{closest_to_first_song, euclidean_distance, DistanceMetric};
 use crate::{BlissError, BlissResult, Song};
 use log::{debug, error, info};
 use std::sync::mpsc;

src/song.rs

@@ -142,7 +142,7 @@ impl fmt::Debug for Analysis {
             debug_struct.field(&format!("{:?}", feature), &self[feature]);
         }
         debug_struct.finish()?;
-        f.write_str(&format!(" /* {:?} */", &self.to_vec()))
+        f.write_str(&format!(" /* {:?} */", &self.as_vec()))
     }
 }
 
@@ -161,7 +161,7 @@ impl Analysis {
     /// Return an ndarray `Array1` representing the analysis' features.
     ///
     /// Particularly useful if you want to make a custom distance metric.
-    pub fn to_arr1(&self) -> Array1<f32> {
+    pub fn as_arr1(&self) -> Array1<f32> {
         arr1(&self.internal_analysis)
     }
 
@@ -169,7 +169,7 @@ impl Analysis {
     ///
     /// Particularly useful if you want iterate through the values to store
     /// them somewhere.
-    pub fn to_vec(&self) -> Vec<f32> {
+    pub fn as_vec(&self) -> Vec<f32> {
         self.internal_analysis.to_vec()
     }
 
@@ -187,7 +187,7 @@ impl Analysis {
     /// Note that almost all distance metrics you will find obey these
     /// properties, so don't sweat it too much.
     pub fn custom_distance(&self, other: &Self, distance: impl DistanceMetric) -> f32 {
-        distance(&self.to_arr1(), &other.to_arr1())
+        distance(&self.as_arr1(), &other.as_arr1())
     }
 }
 
@@ -654,7 +654,7 @@ mod tests {
             -0.9820945,
             -0.95968974,
         ];
-        for (x, y) in song.analysis.to_vec().iter().zip(expected_analysis) {
+        for (x, y) in song.analysis.as_vec().iter().zip(expected_analysis) {
             assert!(0.01 > (x - y).abs());
         }
     }