chore: fix clippy (#283)

* chore: fix clippy


Co-authored-by: Luis Moreno <morenol@users.noreply.github.com>

.github/workflows/ci.yml

@@ -36,7 +36,7 @@ jobs:
       - name: Install Rust toolchain
         uses: actions-rs/toolchain@v1
         with:
-          toolchain: stable
+          toolchain: 1.81 # 1.82 seems to break wasm32 tests https://github.com/rustwasm/wasm-bindgen/issues/4274
           target: ${{ matrix.platform.target }}
           profile: minimal
           default: true

src/algorithm/neighbour/cover_tree.rs

@@ -124,7 +124,7 @@ impl<T: Debug + PartialEq, D: Distance<T>> CoverTree<T, D> {
         current_cover_set.push((d, &self.root));
 
         let mut heap = HeapSelection::with_capacity(k);
-        heap.add(std::f64::MAX);
+        heap.add(f64::MAX);
 
         let mut empty_heap = true;
         if !self.identical_excluded || self.get_data_value(self.root.idx) != p {
@@ -145,7 +145,7 @@ impl<T: Debug + PartialEq, D: Distance<T>> CoverTree<T, D> {
                     }
 
                     let upper_bound = if empty_heap {
-                        std::f64::INFINITY
+                        f64::INFINITY
                     } else {
                         *heap.peek()
                     };
@@ -291,7 +291,7 @@ impl<T: Debug + PartialEq, D: Distance<T>> CoverTree<T, D> {
         } else {
             let max_dist = self.max(point_set);
             let next_scale = (max_scale - 1).min(self.get_scale(max_dist));
-            if next_scale == std::i64::MIN {
+            if next_scale == i64::MIN {
                 let mut children: Vec<Node> = Vec::new();
                 let mut leaf = self.new_leaf(p);
                 children.push(leaf);
@@ -435,7 +435,7 @@ impl<T: Debug + PartialEq, D: Distance<T>> CoverTree<T, D> {
 
     fn get_scale(&self, d: f64) -> i64 {
         if d == 0f64 {
-            std::i64::MIN
+            i64::MIN
         } else {
             (self.inv_log_base * d.ln()).ceil() as i64
         }

src/algorithm/neighbour/fastpair.rs

@@ -52,10 +52,8 @@ pub struct FastPair<'a, T: RealNumber + FloatNumber, M: Array2<T>> {
 }
 
 impl<'a, T: RealNumber + FloatNumber, M: Array2<T>> FastPair<'a, T, M> {
-    ///
     /// Constructor
-    /// Instantiate and inizialise the algorithm
+    /// Instantiate and initialize the algorithm
-    ///
     pub fn new(m: &'a M) -> Result<Self, Failed> {
         if m.shape().0 < 3 {
             return Err(Failed::because(
@@ -74,10 +72,8 @@ impl<'a, T: RealNumber + FloatNumber, M: Array2<T>> FastPair<'a, T, M> {
         Ok(init)
     }
 
-    ///
     /// Initialise `FastPair` by passing a `Array2`.
     /// Build a FastPairs data-structure from a set of (new) points.
-    ///
     fn init(&mut self) {
         // basic measures
         let len = self.samples.shape().0;
@@ -158,9 +154,7 @@ impl<'a, T: RealNumber + FloatNumber, M: Array2<T>> FastPair<'a, T, M> {
         self.neighbours = neighbours;
     }
 
-    ///
     /// Find closest pair by scanning list of nearest neighbors.
-    ///
     #[allow(dead_code)]
     pub fn closest_pair(&self) -> PairwiseDistance<T> {
         let mut a = self.neighbours[0]; // Start with first point
@@ -217,9 +211,7 @@ mod tests_fastpair {
     use super::*;
     use crate::linalg::basic::{arrays::Array, matrix::DenseMatrix};
 
-    ///
     /// Brute force algorithm, used only for comparison and testing
-    ///
     pub fn closest_pair_brute(fastpair: &FastPair<f64, DenseMatrix<f64>>) -> PairwiseDistance<f64> {
         use itertools::Itertools;
         let m = fastpair.samples.shape().0;

src/algorithm/neighbour/linear_search.rs

@@ -61,7 +61,7 @@ impl<T, D: Distance<T>> LinearKNNSearch<T, D> {
 
         for _ in 0..k {
             heap.add(KNNPoint {
-                distance: std::f64::INFINITY,
+                distance: f64::INFINITY,
                 index: None,
             });
         }
@@ -215,7 +215,7 @@ mod tests {
         };
 
         let point_inf = KNNPoint {
-            distance: std::f64::INFINITY,
+            distance: f64::INFINITY,
             index: Some(3),
         };
 

src/algorithm/sort/heap_select.rs

@@ -133,7 +133,7 @@ mod tests {
     #[test]
     fn test_add1() {
         let mut heap = HeapSelection::with_capacity(3);
-        heap.add(std::f64::INFINITY);
+        heap.add(f64::INFINITY);
         heap.add(-5f64);
         heap.add(4f64);
         heap.add(-1f64);
@@ -151,7 +151,7 @@ mod tests {
     #[test]
     fn test_add2() {
         let mut heap = HeapSelection::with_capacity(3);
-        heap.add(std::f64::INFINITY);
+        heap.add(f64::INFINITY);
         heap.add(0.0);
         heap.add(8.4852);
         heap.add(5.6568);

src/algorithm/sort/quick_sort.rs

@@ -3,6 +3,7 @@ use num_traits::Num;
 pub trait QuickArgSort {
     fn quick_argsort_mut(&mut self) -> Vec<usize>;
 
+    #[allow(dead_code)]
     fn quick_argsort(&self) -> Vec<usize>;
 }
 

src/cluster/kmeans.rs

@@ -96,7 +96,7 @@ impl<TX: Number, TY: Number, X: Array2<TX>, Y: Array1<TY>> PartialEq for KMeans<
                     return false;
                 }
                 for j in 0..self.centroids[i].len() {
-                    if (self.centroids[i][j] - other.centroids[i][j]).abs() > std::f64::EPSILON {
+                    if (self.centroids[i][j] - other.centroids[i][j]).abs() > f64::EPSILON {
                         return false;
                     }
                 }
@@ -270,7 +270,7 @@ impl<TX: Number, TY: Number, X: Array2<TX>, Y: Array1<TY>> KMeans<TX, TY, X, Y>
 
         let (n, d) = data.shape();
 
-        let mut distortion = std::f64::MAX;
+        let mut distortion = f64::MAX;
         let mut y = KMeans::<TX, TY, X, Y>::kmeans_plus_plus(data, parameters.k, parameters.seed);
         let mut size = vec![0; parameters.k];
         let mut centroids = vec![vec![0f64; d]; parameters.k];
@@ -331,7 +331,7 @@ impl<TX: Number, TY: Number, X: Array2<TX>, Y: Array1<TY>> KMeans<TX, TY, X, Y>
         let mut row = vec![0f64; x.shape().1];
 
         for i in 0..n {
-            let mut min_dist = std::f64::MAX;
+            let mut min_dist = f64::MAX;
             let mut best_cluster = 0;
 
             for j in 0..self.k {
@@ -361,7 +361,7 @@ impl<TX: Number, TY: Number, X: Array2<TX>, Y: Array1<TY>> KMeans<TX, TY, X, Y>
             .cloned()
             .collect();
 
-        let mut d = vec![std::f64::MAX; n];
+        let mut d = vec![f64::MAX; n];
         let mut row = vec![TX::zero(); data.shape().1];
 
         for j in 1..k {

src/linalg/basic/arrays.rs

@@ -265,11 +265,11 @@ pub trait ArrayView1<T: Debug + Display + Copy + Sized>: Array<T, usize> {
         if p.is_infinite() && p.is_sign_positive() {
             self.iterator(0)
                 .map(|x| x.to_f64().unwrap().abs())
-                .fold(std::f64::NEG_INFINITY, |a, b| a.max(b))
+                .fold(f64::NEG_INFINITY, |a, b| a.max(b))
         } else if p.is_infinite() && p.is_sign_negative() {
             self.iterator(0)
                 .map(|x| x.to_f64().unwrap().abs())
-                .fold(std::f64::INFINITY, |a, b| a.min(b))
+                .fold(f64::INFINITY, |a, b| a.min(b))
         } else {
             let mut norm = 0f64;
 
@@ -558,11 +558,11 @@ pub trait ArrayView2<T: Debug + Display + Copy + Sized>: Array<T, (usize, usize)
         if p.is_infinite() && p.is_sign_positive() {
             self.iterator(0)
                 .map(|x| x.to_f64().unwrap().abs())
-                .fold(std::f64::NEG_INFINITY, |a, b| a.max(b))
+                .fold(f64::NEG_INFINITY, |a, b| a.max(b))
         } else if p.is_infinite() && p.is_sign_negative() {
             self.iterator(0)
                 .map(|x| x.to_f64().unwrap().abs())
-                .fold(std::f64::INFINITY, |a, b| a.min(b))
+                .fold(f64::INFINITY, |a, b| a.min(b))
         } else {
             let mut norm = 0f64;
 
@@ -731,34 +731,34 @@ pub trait MutArrayView1<T: Debug + Display + Copy + Sized>:
 pub trait MutArrayView2<T: Debug + Display + Copy + Sized>:
     MutArray<T, (usize, usize)> + ArrayView2<T>
 {
-    ///
+    /// copy values from another array
     fn copy_from(&mut self, other: &dyn Array<T, (usize, usize)>) {
         self.iterator_mut(0)
             .zip(other.iterator(0))
             .for_each(|(s, o)| *s = *o);
     }
-    ///
+    /// update view with absolute values
     fn abs_mut(&mut self)
     where
         T: Number + Signed,
     {
         self.iterator_mut(0).for_each(|v| *v = v.abs());
     }
-    ///
+    /// update view values with opposite sign
     fn neg_mut(&mut self)
     where
         T: Number + Neg<Output = T>,
     {
         self.iterator_mut(0).for_each(|v| *v = -*v);
     }
-    ///
+    /// update view values at power `p`
     fn pow_mut(&mut self, p: T)
     where
         T: RealNumber,
     {
         self.iterator_mut(0).for_each(|v| *v = v.powf(p));
     }
-    ///
+    /// scale view values
     fn scale_mut(&mut self, mean: &[T], std: &[T], axis: u8)
     where
         T: Number,
@@ -784,27 +784,27 @@ pub trait MutArrayView2<T: Debug + Display + Copy + Sized>:
 
 /// Trait for mutable 1D-array view
 pub trait Array1<T: Debug + Display + Copy + Sized>: MutArrayView1<T> + Sized + Clone {
-    ///
+    /// return a view of the array
     fn slice<'a>(&'a self, range: Range<usize>) -> Box<dyn ArrayView1<T> + 'a>;
-    ///
+    /// return a mutable view of the array
     fn slice_mut<'a>(&'a mut self, range: Range<usize>) -> Box<dyn MutArrayView1<T> + 'a>;
-    ///
+    /// fill array with a given value
     fn fill(len: usize, value: T) -> Self
     where
         Self: Sized;
-    ///
+    /// create array from iterator
     fn from_iterator<I: Iterator<Item = T>>(iter: I, len: usize) -> Self
     where
         Self: Sized;
-    ///
+    /// create array from vector
     fn from_vec_slice(slice: &[T]) -> Self
     where
         Self: Sized;
-    ///
+    /// create array from slice
     fn from_slice(slice: &'_ dyn ArrayView1<T>) -> Self
     where
         Self: Sized;
-    ///
+    /// create a zero array
     fn zeros(len: usize) -> Self
     where
         T: Number,
@@ -812,7 +812,7 @@ pub trait Array1<T: Debug + Display + Copy + Sized>: MutArrayView1<T> + Sized +
     {
         Self::fill(len, T::zero())
     }
-    ///
+    /// create an array of ones
     fn ones(len: usize) -> Self
     where
         T: Number,
@@ -820,7 +820,7 @@ pub trait Array1<T: Debug + Display + Copy + Sized>: MutArrayView1<T> + Sized +
     {
         Self::fill(len, T::one())
     }
-    ///
+    /// create an array of random values
     fn rand(len: usize) -> Self
     where
         T: RealNumber,
@@ -828,7 +828,7 @@ pub trait Array1<T: Debug + Display + Copy + Sized>: MutArrayView1<T> + Sized +
     {
         Self::from_iterator((0..len).map(|_| T::rand()), len)
     }
-    ///
+    /// add a scalar to the array
     fn add_scalar(&self, x: T) -> Self
     where
         T: Number,
@@ -838,7 +838,7 @@ pub trait Array1<T: Debug + Display + Copy + Sized>: MutArrayView1<T> + Sized +
         result.add_scalar_mut(x);
         result
     }
-    ///
+    /// subtract a scalar from the array
     fn sub_scalar(&self, x: T) -> Self
     where
         T: Number,
@@ -848,7 +848,7 @@ pub trait Array1<T: Debug + Display + Copy + Sized>: MutArrayView1<T> + Sized +
         result.sub_scalar_mut(x);
         result
     }
-    ///
+    /// divide a scalar from the array
     fn div_scalar(&self, x: T) -> Self
     where
         T: Number,
@@ -858,7 +858,7 @@ pub trait Array1<T: Debug + Display + Copy + Sized>: MutArrayView1<T> + Sized +
         result.div_scalar_mut(x);
         result
     }
-    ///
+    /// multiply a scalar to the array
     fn mul_scalar(&self, x: T) -> Self
     where
         T: Number,
@@ -868,7 +868,7 @@ pub trait Array1<T: Debug + Display + Copy + Sized>: MutArrayView1<T> + Sized +
         result.mul_scalar_mut(x);
         result
     }
-    ///
+    /// sum of two arrays
     fn add(&self, other: &dyn Array<T, usize>) -> Self
     where
         T: Number,
@@ -878,7 +878,7 @@ pub trait Array1<T: Debug + Display + Copy + Sized>: MutArrayView1<T> + Sized +
         result.add_mut(other);
         result
     }
-    ///
+    /// subtract two arrays
     fn sub(&self, other: &impl Array1<T>) -> Self
     where
         T: Number,
@@ -888,7 +888,7 @@ pub trait Array1<T: Debug + Display + Copy + Sized>: MutArrayView1<T> + Sized +
         result.sub_mut(other);
         result
     }
-    ///
+    /// multiply two arrays
     fn mul(&self, other: &dyn Array<T, usize>) -> Self
     where
         T: Number,
@@ -898,7 +898,7 @@ pub trait Array1<T: Debug + Display + Copy + Sized>: MutArrayView1<T> + Sized +
         result.mul_mut(other);
         result
     }
-    ///
+    /// divide two arrays
     fn div(&self, other: &dyn Array<T, usize>) -> Self
     where
         T: Number,
@@ -908,7 +908,7 @@ pub trait Array1<T: Debug + Display + Copy + Sized>: MutArrayView1<T> + Sized +
         result.div_mut(other);
         result
     }
-    ///
+    /// replace values with another array
     fn take(&self, index: &[usize]) -> Self
     where
         Self: Sized,
@@ -920,7 +920,7 @@ pub trait Array1<T: Debug + Display + Copy + Sized>: MutArrayView1<T> + Sized +
         );
         Self::from_iterator(index.iter().map(move |&i| *self.get(i)), index.len())
     }
-    ///
+    /// create a view of the array with absolute values
     fn abs(&self) -> Self
     where
         T: Number + Signed,
@@ -930,7 +930,7 @@ pub trait Array1<T: Debug + Display + Copy + Sized>: MutArrayView1<T> + Sized +
         result.abs_mut();
         result
     }
-    ///
+    /// create a view of the array with opposite sign
     fn neg(&self) -> Self
     where
         T: Number + Neg<Output = T>,
@@ -940,7 +940,7 @@ pub trait Array1<T: Debug + Display + Copy + Sized>: MutArrayView1<T> + Sized +
         result.neg_mut();
         result
     }
-    ///
+    /// create a view of the array with values at power `p`
     fn pow(&self, p: T) -> Self
     where
         T: RealNumber,
@@ -950,7 +950,7 @@ pub trait Array1<T: Debug + Display + Copy + Sized>: MutArrayView1<T> + Sized +
         result.pow_mut(p);
         result
     }
-    ///
+    /// apply argsort to the array
     fn argsort(&self) -> Vec<usize>
     where
         T: Number + PartialOrd,
@@ -958,12 +958,12 @@ pub trait Array1<T: Debug + Display + Copy + Sized>: MutArrayView1<T> + Sized +
         let mut v = self.clone();
         v.argsort_mut()
     }
-    ///
+    /// map values of the array
     fn map<O: Debug + Display + Copy + Sized, A: Array1<O>, F: FnMut(&T) -> O>(self, f: F) -> A {
         let len = self.shape();
         A::from_iterator(self.iterator(0).map(f), len)
     }
-    ///
+    /// apply softmax to the array
     fn softmax(&self) -> Self
     where
         T: RealNumber,
@@ -973,7 +973,7 @@ pub trait Array1<T: Debug + Display + Copy + Sized>: MutArrayView1<T> + Sized +
         result.softmax_mut();
         result
     }
-    ///
+    /// multiply array by matrix
     fn xa(&self, a_transpose: bool, a: &dyn ArrayView2<T>) -> Self
     where
         T: Number,
@@ -1003,7 +1003,7 @@ pub trait Array1<T: Debug + Display + Copy + Sized>: MutArrayView1<T> + Sized +
         result
     }
 
-    ///
+    /// check if two arrays are approximately equal
     fn approximate_eq(&self, other: &Self, error: T) -> bool
     where
         T: Number + RealNumber,
@@ -1015,13 +1015,13 @@ pub trait Array1<T: Debug + Display + Copy + Sized>: MutArrayView1<T> + Sized +
 
 /// Trait for mutable 2D-array view
 pub trait Array2<T: Debug + Display + Copy + Sized>: MutArrayView2<T> + Sized + Clone {
-    ///
+    /// fill 2d array with a given value
     fn fill(nrows: usize, ncols: usize, value: T) -> Self;
-    ///
+    /// get a view of the 2d array
     fn slice<'a>(&'a self, rows: Range<usize>, cols: Range<usize>) -> Box<dyn ArrayView2<T> + 'a>
     where
         Self: Sized;
-    ///
+    /// get a mutable view of the 2d array
     fn slice_mut<'a>(
         &'a mut self,
         rows: Range<usize>,
@@ -1029,31 +1029,31 @@ pub trait Array2<T: Debug + Display + Copy + Sized>: MutArrayView2<T> + Sized +
     ) -> Box<dyn MutArrayView2<T> + 'a>
     where
         Self: Sized;
-    ///
+    /// create 2d array from iterator
     fn from_iterator<I: Iterator<Item = T>>(iter: I, nrows: usize, ncols: usize, axis: u8) -> Self;
-    ///
+    /// get row from 2d array
     fn get_row<'a>(&'a self, row: usize) -> Box<dyn ArrayView1<T> + 'a>
     where
         Self: Sized;
-    ///
+    /// get column from 2d array
     fn get_col<'a>(&'a self, col: usize) -> Box<dyn ArrayView1<T> + 'a>
     where
         Self: Sized;
-    ///
+    /// create a zero 2d array
     fn zeros(nrows: usize, ncols: usize) -> Self
     where
         T: Number,
     {
         Self::fill(nrows, ncols, T::zero())
     }
-    ///
+    /// create a 2d array of ones
     fn ones(nrows: usize, ncols: usize) -> Self
     where
         T: Number,
     {
         Self::fill(nrows, ncols, T::one())
     }
-    ///
+    /// create an identity matrix
     fn eye(size: usize) -> Self
     where
         T: Number,
@@ -1066,29 +1066,29 @@ pub trait Array2<T: Debug + Display + Copy + Sized>: MutArrayView2<T> + Sized +
 
         matrix
     }
-    ///
+    /// create a 2d array of random values
     fn rand(nrows: usize, ncols: usize) -> Self
     where
         T: RealNumber,
     {
         Self::from_iterator((0..nrows * ncols).map(|_| T::rand()), nrows, ncols, 0)
     }
-    ///
+    /// crate from 2d slice
     fn from_slice(slice: &dyn ArrayView2<T>) -> Self {
         let (nrows, ncols) = slice.shape();
         Self::from_iterator(slice.iterator(0).cloned(), nrows, ncols, 0)
     }
-    ///
+    /// create from row
     fn from_row(slice: &dyn ArrayView1<T>) -> Self {
         let ncols = slice.shape();
         Self::from_iterator(slice.iterator(0).cloned(), 1, ncols, 0)
     }
-    ///
+    /// create from column
     fn from_column(slice: &dyn ArrayView1<T>) -> Self {
         let nrows = slice.shape();
         Self::from_iterator(slice.iterator(0).cloned(), nrows, 1, 0)
     }
-    ///
+    /// transpose 2d array
     fn transpose(&self) -> Self {
         let (nrows, ncols) = self.shape();
         let mut m = Self::fill(ncols, nrows, *self.get((0, 0)));
@@ -1099,7 +1099,7 @@ pub trait Array2<T: Debug + Display + Copy + Sized>: MutArrayView2<T> + Sized +
         }
         m
     }
-    ///
+    /// change shape of 2d array
     fn reshape(&self, nrows: usize, ncols: usize, axis: u8) -> Self {
         let (onrows, oncols) = self.shape();
 
@@ -1110,7 +1110,7 @@ pub trait Array2<T: Debug + Display + Copy + Sized>: MutArrayView2<T> + Sized +
 
         Self::from_iterator(self.iterator(0).cloned(), nrows, ncols, axis)
     }
-    ///
+    /// multiply two 2d arrays
     fn matmul(&self, other: &dyn ArrayView2<T>) -> Self
     where
         T: Number,
@@ -1136,7 +1136,7 @@ pub trait Array2<T: Debug + Display + Copy + Sized>: MutArrayView2<T> + Sized +
 
         result
     }
-    ///
+    /// matrix multiplication
     fn ab(&self, a_transpose: bool, b: &dyn ArrayView2<T>, b_transpose: bool) -> Self
     where
         T: Number,
@@ -1171,7 +1171,7 @@ pub trait Array2<T: Debug + Display + Copy + Sized>: MutArrayView2<T> + Sized +
             result
         }
     }
-    ///
+    /// matrix vector multiplication
     fn ax(&self, a_transpose: bool, x: &dyn ArrayView1<T>) -> Self
     where
         T: Number,
@@ -1199,7 +1199,7 @@ pub trait Array2<T: Debug + Display + Copy + Sized>: MutArrayView2<T> + Sized +
         }
         result
     }
-    ///
+    /// concatenate 1d array
     fn concatenate_1d<'a>(arrays: &'a [&'a dyn ArrayView1<T>], axis: u8) -> Self {
         assert!(
             axis == 1 || axis == 0,
@@ -1237,7 +1237,7 @@ pub trait Array2<T: Debug + Display + Copy + Sized>: MutArrayView2<T> + Sized +
             ),
         }
     }
-    ///
+    /// concatenate 2d array
     fn concatenate_2d<'a>(arrays: &'a [&'a dyn ArrayView2<T>], axis: u8) -> Self {
         assert!(
             axis == 1 || axis == 0,
@@ -1294,7 +1294,7 @@ pub trait Array2<T: Debug + Display + Copy + Sized>: MutArrayView2<T> + Sized +
             }
         }
     }
-    ///
+    /// merge 1d arrays
     fn merge_1d<'a>(&'a self, arrays: &'a [&'a dyn ArrayView1<T>], axis: u8, append: bool) -> Self {
         assert!(
             axis == 1 || axis == 0,
@@ -1362,7 +1362,7 @@ pub trait Array2<T: Debug + Display + Copy + Sized>: MutArrayView2<T> + Sized +
             }
         }
     }
-    ///
+    /// Stack arrays in sequence vertically
     fn v_stack(&self, other: &dyn ArrayView2<T>) -> Self {
         let (nrows, ncols) = self.shape();
         let (other_nrows, other_ncols) = other.shape();
@@ -1378,7 +1378,7 @@ pub trait Array2<T: Debug + Display + Copy + Sized>: MutArrayView2<T> + Sized +
             0,
         )
     }
-    ///
+    /// Stack arrays in sequence horizontally
     fn h_stack(&self, other: &dyn ArrayView2<T>) -> Self {
         let (nrows, ncols) = self.shape();
         let (other_nrows, other_ncols) = other.shape();
@@ -1394,20 +1394,20 @@ pub trait Array2<T: Debug + Display + Copy + Sized>: MutArrayView2<T> + Sized +
             1,
         )
     }
-    ///
+    /// map  array values
     fn map<O: Debug + Display + Copy + Sized, A: Array2<O>, F: FnMut(&T) -> O>(self, f: F) -> A {
         let (nrows, ncols) = self.shape();
         A::from_iterator(self.iterator(0).map(f), nrows, ncols, 0)
     }
-    ///
+    /// iter rows
     fn row_iter<'a>(&'a self) -> Box<dyn Iterator<Item = Box<dyn ArrayView1<T> + 'a>> + 'a> {
         Box::new((0..self.shape().0).map(move |r| self.get_row(r)))
     }
-    ///
+    /// iter cols
     fn col_iter<'a>(&'a self) -> Box<dyn Iterator<Item = Box<dyn ArrayView1<T> + 'a>> + 'a> {
         Box::new((0..self.shape().1).map(move |r| self.get_col(r)))
     }
-    ///
+    /// take elements from 2d array
     fn take(&self, index: &[usize], axis: u8) -> Self {
         let (nrows, ncols) = self.shape();
 
@@ -1447,7 +1447,7 @@ pub trait Array2<T: Debug + Display + Copy + Sized>: MutArrayView2<T> + Sized +
     fn take_column(&self, column_index: usize) -> Self {
         self.take(&[column_index], 1)
     }
-    ///
+    /// add a scalar to the array
     fn add_scalar(&self, x: T) -> Self
     where
         T: Number,
@@ -1456,7 +1456,7 @@ pub trait Array2<T: Debug + Display + Copy + Sized>: MutArrayView2<T> + Sized +
         result.add_scalar_mut(x);
         result
     }
-    ///
+    /// subtract a scalar from the array
     fn sub_scalar(&self, x: T) -> Self
     where
         T: Number,
@@ -1465,7 +1465,7 @@ pub trait Array2<T: Debug + Display + Copy + Sized>: MutArrayView2<T> + Sized +
         result.sub_scalar_mut(x);
         result
     }
-    ///
+    /// divide a scalar from the array
     fn div_scalar(&self, x: T) -> Self
     where
         T: Number,
@@ -1474,7 +1474,7 @@ pub trait Array2<T: Debug + Display + Copy + Sized>: MutArrayView2<T> + Sized +
         result.div_scalar_mut(x);
         result
     }
-    ///
+    /// multiply a scalar to the array
     fn mul_scalar(&self, x: T) -> Self
     where
         T: Number,
@@ -1483,7 +1483,7 @@ pub trait Array2<T: Debug + Display + Copy + Sized>: MutArrayView2<T> + Sized +
         result.mul_scalar_mut(x);
         result
     }
-    ///
+    /// sum of two arrays
     fn add(&self, other: &dyn Array<T, (usize, usize)>) -> Self
     where
         T: Number,
@@ -1492,7 +1492,7 @@ pub trait Array2<T: Debug + Display + Copy + Sized>: MutArrayView2<T> + Sized +
         result.add_mut(other);
         result
     }
-    ///
+    /// subtract two arrays
     fn sub(&self, other: &dyn Array<T, (usize, usize)>) -> Self
     where
         T: Number,
@@ -1501,7 +1501,7 @@ pub trait Array2<T: Debug + Display + Copy + Sized>: MutArrayView2<T> + Sized +
         result.sub_mut(other);
         result
     }
-    ///
+    /// multiply two arrays
     fn mul(&self, other: &dyn Array<T, (usize, usize)>) -> Self
     where
         T: Number,
@@ -1510,7 +1510,7 @@ pub trait Array2<T: Debug + Display + Copy + Sized>: MutArrayView2<T> + Sized +
         result.mul_mut(other);
         result
     }
-    ///
+    /// divide two arrays
     fn div(&self, other: &dyn Array<T, (usize, usize)>) -> Self
     where
         T: Number,
@@ -1519,7 +1519,7 @@ pub trait Array2<T: Debug + Display + Copy + Sized>: MutArrayView2<T> + Sized +
         result.div_mut(other);
         result
     }
-    ///
+    /// absolute values of the array
     fn abs(&self) -> Self
     where
         T: Number + Signed,
@@ -1528,7 +1528,7 @@ pub trait Array2<T: Debug + Display + Copy + Sized>: MutArrayView2<T> + Sized +
         result.abs_mut();
         result
     }
-    ///
+    /// negation of the array
     fn neg(&self) -> Self
     where
         T: Number + Neg<Output = T>,
@@ -1537,7 +1537,7 @@ pub trait Array2<T: Debug + Display + Copy + Sized>: MutArrayView2<T> + Sized +
         result.neg_mut();
         result
     }
-    ///
+    /// values at power `p`
     fn pow(&self, p: T) -> Self
     where
         T: RealNumber,
@@ -1575,7 +1575,7 @@ pub trait Array2<T: Debug + Display + Copy + Sized>: MutArrayView2<T> + Sized +
         }
     }
 
-    /// appriximate equality of the elements of a matrix according to a given error
+    /// approximate equality of the elements of a matrix according to a given error
     fn approximate_eq(&self, other: &Self, error: T) -> bool
     where
         T: Number + RealNumber,
@@ -1631,8 +1631,8 @@ mod tests {
         let v = vec![3., -2., 6.];
         assert_eq!(v.norm(1.), 11.);
         assert_eq!(v.norm(2.), 7.);
-        assert_eq!(v.norm(std::f64::INFINITY), 6.);
+        assert_eq!(v.norm(f64::INFINITY), 6.);
-        assert_eq!(v.norm(std::f64::NEG_INFINITY), 2.);
+        assert_eq!(v.norm(f64::NEG_INFINITY), 2.);
     }
 
     #[test]

src/linalg/traits/evd.rs

@@ -841,7 +841,7 @@ mod tests {
         ));
         for (i, eigen_values_i) in eigen_values.iter().enumerate() {
             assert!((eigen_values_i - evd.d[i]).abs() < 1e-4);
-            assert!((0f64 - evd.e[i]).abs() < std::f64::EPSILON);
+            assert!((0f64 - evd.e[i]).abs() < f64::EPSILON);
         }
     }
     #[cfg_attr(
@@ -875,7 +875,7 @@ mod tests {
         ));
         for (i, eigen_values_i) in eigen_values.iter().enumerate() {
             assert!((eigen_values_i - evd.d[i]).abs() < 1e-4);
-            assert!((0f64 - evd.e[i]).abs() < std::f64::EPSILON);
+            assert!((0f64 - evd.e[i]).abs() < f64::EPSILON);
         }
     }
     #[cfg_attr(

src/linalg/traits/stats.rs

@@ -217,8 +217,8 @@ mod tests {
         let expected_0 = vec![0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0];
         let expected_1 = vec![1.25, 1.25];
 
-        assert!(m.var(0).approximate_eq(&expected_0, std::f64::EPSILON));
+        assert!(m.var(0).approximate_eq(&expected_0, f64::EPSILON));
-        assert!(m.var(1).approximate_eq(&expected_1, std::f64::EPSILON));
+        assert!(m.var(1).approximate_eq(&expected_1, f64::EPSILON));
         assert_eq!(
             m.mean(0),
             vec![0.0, 0.25, 0.25, 1.25, 1.5, 1.75, 2.75, 3.25]

src/linalg/traits/svd.rs

@@ -48,11 +48,9 @@ pub struct SVD<T: Number + RealNumber, M: SVDDecomposable<T>> {
     pub V: M,
     /// Singular values of the original matrix
     pub s: Vec<T>,
-    ///
     m: usize,
-    ///
     n: usize,
-    ///
+    /// Tolerance
     tol: T,
 }
 

src/linear/bg_solver.rs

@@ -27,9 +27,9 @@ use crate::error::Failed;
 use crate::linalg::basic::arrays::{Array, Array1, Array2, ArrayView1, MutArrayView1};
 use crate::numbers::floatnum::FloatNumber;
 
-///
+/// Trait for Biconjugate Gradient Solver
 pub trait BiconjugateGradientSolver<'a, T: FloatNumber, X: Array2<T>> {
-    ///
+    /// Solve Ax = b
     fn solve_mut(
         &self,
         a: &'a X,
@@ -109,7 +109,7 @@ pub trait BiconjugateGradientSolver<'a, T: FloatNumber, X: Array2<T>> {
         Ok(err)
     }
 
-    ///
+    /// solve preconditioner
     fn solve_preconditioner(&self, a: &'a X, b: &[T], x: &mut [T]) {
         let diag = Self::diag(a);
         let n = diag.len();
@@ -133,7 +133,7 @@ pub trait BiconjugateGradientSolver<'a, T: FloatNumber, X: Array2<T>> {
         y.copy_from(&x.xa(true, a));
     }
 
-    ///
+    /// Extract the diagonal from a matrix
     fn diag(a: &X) -> Vec<T> {
         let (nrows, ncols) = a.shape();
         let n = nrows.min(ncols);

src/linear/lasso_optimizer.rs

@@ -16,7 +16,7 @@ use crate::linalg::basic::arrays::{Array1, Array2, ArrayView1, MutArray, MutArra
 use crate::linear::bg_solver::BiconjugateGradientSolver;
 use crate::numbers::floatnum::FloatNumber;
 
-///
+/// Interior Point Optimizer
 pub struct InteriorPointOptimizer<T: FloatNumber, X: Array2<T>> {
     ata: X,
     d1: Vec<T>,
@@ -25,9 +25,8 @@ pub struct InteriorPointOptimizer<T: FloatNumber, X: Array2<T>> {
     prs: Vec<T>,
 }
 
-///
 impl<T: FloatNumber, X: Array2<T>> InteriorPointOptimizer<T, X> {
-    ///
+    /// Initialize a new Interior Point Optimizer
     pub fn new(a: &X, n: usize) -> InteriorPointOptimizer<T, X> {
         InteriorPointOptimizer {
             ata: a.ab(true, a, false),
@@ -38,7 +37,7 @@ impl<T: FloatNumber, X: Array2<T>> InteriorPointOptimizer<T, X> {
         }
     }
 
-    ///
+    /// Run the optimization
     pub fn optimize(
         &mut self,
         x: &X,
@@ -101,7 +100,7 @@ impl<T: FloatNumber, X: Array2<T>> InteriorPointOptimizer<T, X> {
 
             // CALCULATE DUALITY GAP
             let xnu = nu.xa(false, x);
-            let max_xnu = xnu.norm(std::f64::INFINITY);
+            let max_xnu = xnu.norm(f64::INFINITY);
             if max_xnu > lambda_f64 {
                 let lnu = T::from_f64(lambda_f64 / max_xnu).unwrap();
                 nu.mul_scalar_mut(lnu);
@@ -208,7 +207,6 @@ impl<T: FloatNumber, X: Array2<T>> InteriorPointOptimizer<T, X> {
         Ok(w)
     }
 
-    ///
     fn sumlogneg(f: &X) -> T {
         let (n, _) = f.shape();
         let mut sum = T::zero();
@@ -220,11 +218,9 @@ impl<T: FloatNumber, X: Array2<T>> InteriorPointOptimizer<T, X> {
     }
 }
 
-///
 impl<'a, T: FloatNumber, X: Array2<T>> BiconjugateGradientSolver<'a, T, X>
     for InteriorPointOptimizer<T, X>
 {
-    ///
     fn solve_preconditioner(&self, a: &'a X, b: &[T], x: &mut [T]) {
         let (_, p) = a.shape();
 
@@ -234,7 +230,6 @@ impl<'a, T: FloatNumber, X: Array2<T>> BiconjugateGradientSolver<'a, T, X>
         }
     }
 
-    ///
     fn mat_vec_mul(&self, _: &X, x: &Vec<T>, y: &mut Vec<T>) {
         let (_, p) = self.ata.shape();
         let x_slice = Vec::from_slice(x.slice(0..p).as_ref());
@@ -246,7 +241,6 @@ impl<'a, T: FloatNumber, X: Array2<T>> BiconjugateGradientSolver<'a, T, X>
         }
     }
 
-    ///
     fn mat_t_vec_mul(&self, a: &X, x: &Vec<T>, y: &mut Vec<T>) {
         self.mat_vec_mul(a, x, y);
     }

src/linear/logistic_regression.rs

@@ -183,14 +183,11 @@ pub struct LogisticRegression<
 }
 
 trait ObjectiveFunction<T: Number + FloatNumber, X: Array2<T>> {
-    ///
     fn f(&self, w_bias: &[T]) -> T;
 
-    ///
     #[allow(clippy::ptr_arg)]
     fn df(&self, g: &mut Vec<T>, w_bias: &Vec<T>);
 
-    ///
     #[allow(clippy::ptr_arg)]
     fn partial_dot(w: &[T], x: &X, v_col: usize, m_row: usize) -> T {
         let mut sum = T::zero();
@@ -629,11 +626,11 @@ mod tests {
         objective.df(&mut g, &vec![1., 2., 3., 4., 5., 6., 7., 8., 9.]);
         objective.df(&mut g, &vec![1., 2., 3., 4., 5., 6., 7., 8., 9.]);
 
-        assert!((g[0] + 33.000068218163484).abs() < std::f64::EPSILON);
+        assert!((g[0] + 33.000068218163484).abs() < f64::EPSILON);
 
         let f = objective.f(&[1., 2., 3., 4., 5., 6., 7., 8., 9.]);
 
-        assert!((f - 408.0052230582765).abs() < std::f64::EPSILON);
+        assert!((f - 408.0052230582765).abs() < f64::EPSILON);
 
         let objective_reg = MultiClassObjectiveFunction {
             x: &x,
@@ -689,13 +686,13 @@ mod tests {
         objective.df(&mut g, &vec![1., 2., 3.]);
         objective.df(&mut g, &vec![1., 2., 3.]);
 
-        assert!((g[0] - 26.051064349381285).abs() < std::f64::EPSILON);
+        assert!((g[0] - 26.051064349381285).abs() < f64::EPSILON);
-        assert!((g[1] - 10.239000702928523).abs() < std::f64::EPSILON);
+        assert!((g[1] - 10.239000702928523).abs() < f64::EPSILON);
-        assert!((g[2] - 3.869294270156324).abs() < std::f64::EPSILON);
+        assert!((g[2] - 3.869294270156324).abs() < f64::EPSILON);
 
         let f = objective.f(&[1., 2., 3.]);
 
-        assert!((f - 59.76994756647412).abs() < std::f64::EPSILON);
+        assert!((f - 59.76994756647412).abs() < f64::EPSILON);
 
         let objective_reg = BinaryObjectiveFunction {
             x: &x,
@@ -916,7 +913,7 @@ mod tests {
         let x: DenseMatrix<f32> = DenseMatrix::rand(52181, 94);
         let y1: Vec<i32> = vec![1; 2181];
         let y2: Vec<i32> = vec![0; 50000];
-        let y: Vec<i32> = y1.into_iter().chain(y2.into_iter()).collect();
+        let y: Vec<i32> = y1.into_iter().chain(y2).collect();
 
         let lr = LogisticRegression::fit(&x, &y, Default::default()).unwrap();
         let lr_reg = LogisticRegression::fit(
@@ -938,12 +935,12 @@ mod tests {
         let x: &DenseMatrix<f64> = &DenseMatrix::rand(52181, 94);
         let y1: Vec<u32> = vec![1; 2181];
         let y2: Vec<u32> = vec![0; 50000];
-        let y: &Vec<u32> = &(y1.into_iter().chain(y2.into_iter()).collect());
+        let y: &Vec<u32> = &(y1.into_iter().chain(y2).collect());
         println!("y vec height: {:?}", y.len());
         println!("x matrix shape: {:?}", x.shape());
 
         let lr = LogisticRegression::fit(x, y, Default::default()).unwrap();
-        let y_hat = lr.predict(&x).unwrap();
+        let y_hat = lr.predict(x).unwrap();
 
         println!("y_hat shape: {:?}", y_hat.shape());
 

src/naive_bayes/bernoulli.rs

@@ -427,6 +427,7 @@ impl<TX: Number + PartialOrd, TY: Number + Ord + Unsigned, X: Array2<TX>, Y: Arr
 
     /// Estimates the class labels for the provided data.
     /// * `x` - data of shape NxM where N is number of data points to estimate and M is number of features.
+    ///
     /// Returns a vector of size N with class estimates.
     pub fn predict(&self, x: &X) -> Result<Y, Failed> {
         if let Some(threshold) = self.binarize {

src/naive_bayes/categorical.rs

@@ -95,7 +95,7 @@ impl<T: Number + Unsigned> PartialEq for CategoricalNBDistribution<T> {
                         return false;
                     }
                     for (a_i_j, b_i_j) in a_i.iter().zip(b_i.iter()) {
-                        if (*a_i_j - *b_i_j).abs() > std::f64::EPSILON {
+                        if (*a_i_j - *b_i_j).abs() > f64::EPSILON {
                             return false;
                         }
                     }
@@ -375,6 +375,7 @@ impl<T: Number + Unsigned, X: Array2<T>, Y: Array1<T>> CategoricalNB<T, X, Y> {
 
     /// Estimates the class labels for the provided data.
     /// * `x` - data of shape NxM where N is number of data points to estimate and M is number of features.
+    ///
     /// Returns a vector of size N with class estimates.
     pub fn predict(&self, x: &X) -> Result<Y, Failed> {
         self.inner.as_ref().unwrap().predict(x)

src/naive_bayes/gaussian.rs

@@ -328,6 +328,7 @@ impl<TX: Number + RealNumber, TY: Number + Ord + Unsigned, X: Array2<TX>, Y: Arr
 
     /// Estimates the class labels for the provided data.
     /// * `x` - data of shape NxM where N is number of data points to estimate and M is number of features.
+    ///
     /// Returns a vector of size N with class estimates.
     pub fn predict(&self, x: &X) -> Result<Y, Failed> {
         self.inner.as_ref().unwrap().predict(x)

src/naive_bayes/mod.rs

@@ -89,6 +89,7 @@ impl<TX: Number, TY: Number, X: Array2<TX>, Y: Array1<TY>, D: NBDistribution<TX,
 
     /// Estimates the class labels for the provided data.
     /// * `x` - data of shape NxM where N is number of data points to estimate and M is number of features.
+    ///
     /// Returns a vector of size N with class estimates.
     pub fn predict(&self, x: &X) -> Result<Y, Failed> {
         let y_classes = self.distribution.classes();
@@ -163,7 +164,7 @@ mod tests {
         }
 
         fn classes(&self) -> &Vec<i32> {
-            &self.0
+            self.0
         }
     }
 

src/naive_bayes/multinomial.rs

@@ -358,6 +358,7 @@ impl<TX: Number + Unsigned, TY: Number + Ord + Unsigned, X: Array2<TX>, Y: Array
 
     /// Estimates the class labels for the provided data.
     /// * `x` - data of shape NxM where N is number of data points to estimate and M is number of features.
+    ///
     /// Returns a vector of size N with class estimates.
     pub fn predict(&self, x: &X) -> Result<Y, Failed> {
         self.inner.as_ref().unwrap().predict(x)

src/neighbors/knn_classifier.rs

@@ -261,6 +261,7 @@ impl<TX: Number, TY: Number + Ord, X: Array2<TX>, Y: Array1<TY>, D: Distance<Vec
 
     /// Estimates the class labels for the provided data.
     /// * `x` - data of shape NxM where N is number of data points to estimate and M is number of features.
+    ///
     /// Returns a vector of size N with class estimates.
     pub fn predict(&self, x: &X) -> Result<Y, Failed> {
         let mut result = Y::zeros(x.shape().0);

src/neighbors/knn_regressor.rs

@@ -88,25 +88,21 @@ pub struct KNNRegressor<TX: Number, TY: Number, X: Array2<TX>, Y: Array1<TY>, D:
 impl<TX: Number, TY: Number, X: Array2<TX>, Y: Array1<TY>, D: Distance<Vec<TX>>>
     KNNRegressor<TX, TY, X, Y, D>
 {
-    ///
     fn y(&self) -> &Y {
         self.y.as_ref().unwrap()
     }
 
-    ///
     fn knn_algorithm(&self) -> &KNNAlgorithm<TX, D> {
         self.knn_algorithm
             .as_ref()
             .expect("Missing parameter: KNNAlgorithm")
     }
 
-    ///
     fn weight(&self) -> &KNNWeightFunction {
         self.weight.as_ref().expect("Missing parameter: weight")
     }
 
     #[allow(dead_code)]
-    ///
     fn k(&self) -> usize {
         self.k.unwrap()
     }
@@ -250,6 +246,7 @@ impl<TX: Number, TY: Number, X: Array2<TX>, Y: Array1<TY>, D: Distance<Vec<TX>>>
 
     /// Predict the target for the provided data.
     /// * `x` - data of shape NxM where N is number of data points to estimate and M is number of features.
+    ///
     /// Returns a vector of size N with estimates.
     pub fn predict(&self, x: &X) -> Result<Y, Failed> {
         let mut result = Y::zeros(x.shape().0);
@@ -312,7 +309,7 @@ mod tests {
         let y_hat = knn.predict(&x).unwrap();
         assert_eq!(5, Vec::len(&y_hat));
         for i in 0..y_hat.len() {
-            assert!((y_hat[i] - y_exp[i]).abs() < std::f64::EPSILON);
+            assert!((y_hat[i] - y_exp[i]).abs() < f64::EPSILON);
         }
     }
 

src/optimization/first_order/gradient_descent.rs

@@ -1,5 +1,3 @@
-// TODO: missing documentation
-
 use std::default::Default;
 
 use crate::linalg::basic::arrays::Array1;
@@ -8,30 +6,27 @@ use crate::optimization::first_order::{FirstOrderOptimizer, OptimizerResult};
 use crate::optimization::line_search::LineSearchMethod;
 use crate::optimization::{DF, F};
 
-///
+/// Gradient Descent optimization algorithm
 pub struct GradientDescent {
-    ///
+    /// Maximum number of iterations
     pub max_iter: usize,
-    ///
+    /// Relative tolerance for the gradient norm
     pub g_rtol: f64,
-    ///
+    /// Absolute tolerance for the gradient norm
     pub g_atol: f64,
 }
 
-///
 impl Default for GradientDescent {
     fn default() -> Self {
         GradientDescent {
             max_iter: 10000,
-            g_rtol: std::f64::EPSILON.sqrt(),
+            g_rtol: f64::EPSILON.sqrt(),
-            g_atol: std::f64::EPSILON,
+            g_atol: f64::EPSILON,
         }
     }
 }
 
-///
 impl<T: FloatNumber> FirstOrderOptimizer<T> for GradientDescent {
-    ///
     fn optimize<'a, X: Array1<T>, LS: LineSearchMethod<T>>(
         &self,
         f: &'a F<'_, T, X>,

src/optimization/first_order/lbfgs.rs

@@ -11,31 +11,29 @@ use crate::optimization::first_order::{FirstOrderOptimizer, OptimizerResult};
 use crate::optimization::line_search::LineSearchMethod;
 use crate::optimization::{DF, F};
 
-///
+/// Limited-memory BFGS optimization algorithm
 pub struct LBFGS {
-    ///
+    /// Maximum number of iterations
     pub max_iter: usize,
-    ///
+    /// TODO: Add documentation
     pub g_rtol: f64,
-    ///
+    /// TODO: Add documentation
     pub g_atol: f64,
-    ///
+    /// TODO: Add documentation
     pub x_atol: f64,
-    ///
+    /// TODO: Add documentation
     pub x_rtol: f64,
-    ///
+    /// TODO: Add documentation
     pub f_abstol: f64,
-    ///
+    /// TODO: Add documentation
     pub f_reltol: f64,
-    ///
+    /// TODO: Add documentation
     pub successive_f_tol: usize,
-    ///
+    /// TODO: Add documentation
     pub m: usize,
 }
 
-///
 impl Default for LBFGS {
-    ///
     fn default() -> Self {
         LBFGS {
             max_iter: 1000,
@@ -51,9 +49,7 @@ impl Default for LBFGS {
     }
 }
 
-///
 impl LBFGS {
-    ///
     fn two_loops<T: FloatNumber + RealNumber, X: Array1<T>>(&self, state: &mut LBFGSState<T, X>) {
         let lower = state.iteration.max(self.m) - self.m;
         let upper = state.iteration;
@@ -95,7 +91,6 @@ impl LBFGS {
         state.s.mul_scalar_mut(-T::one());
     }
 
-    ///
     fn init_state<T: FloatNumber + RealNumber, X: Array1<T>>(&self, x: &X) -> LBFGSState<T, X> {
         LBFGSState {
             x: x.clone(),
@@ -119,7 +114,6 @@ impl LBFGS {
         }
     }
 
-    ///
     fn update_state<'a, T: FloatNumber + RealNumber, X: Array1<T>, LS: LineSearchMethod<T>>(
         &self,
         f: &'a F<'_, T, X>,
@@ -161,7 +155,6 @@ impl LBFGS {
         df(&mut state.x_df, &state.x);
     }
 
-    ///
     fn assess_convergence<T: FloatNumber, X: Array1<T>>(
         &self,
         state: &mut LBFGSState<T, X>,
@@ -173,7 +166,7 @@ impl LBFGS {
         }
 
         if state.x.max_diff(&state.x_prev)
-            <= T::from_f64(self.x_rtol * state.x.norm(std::f64::INFINITY)).unwrap()
+            <= T::from_f64(self.x_rtol * state.x.norm(f64::INFINITY)).unwrap()
         {
             x_converged = true;
         }
@@ -188,14 +181,13 @@ impl LBFGS {
             state.counter_f_tol += 1;
         }
 
-        if state.x_df.norm(std::f64::INFINITY) <= self.g_atol {
+        if state.x_df.norm(f64::INFINITY) <= self.g_atol {
             g_converged = true;
         }
 
         g_converged || x_converged || state.counter_f_tol > self.successive_f_tol
     }
 
-    ///
     fn update_hessian<T: FloatNumber, X: Array1<T>>(
         &self,
         _: &DF<'_, X>,
@@ -212,7 +204,6 @@ impl LBFGS {
     }
 }
 
-///
 #[derive(Debug)]
 struct LBFGSState<T: FloatNumber, X: Array1<T>> {
     x: X,
@@ -234,9 +225,7 @@ struct LBFGSState<T: FloatNumber, X: Array1<T>> {
     alpha: T,
 }
 
-///
 impl<T: FloatNumber + RealNumber> FirstOrderOptimizer<T> for LBFGS {
-    ///
     fn optimize<'a, X: Array1<T>, LS: LineSearchMethod<T>>(
         &self,
         f: &F<'_, T, X>,
@@ -248,7 +237,7 @@ impl<T: FloatNumber + RealNumber> FirstOrderOptimizer<T> for LBFGS {
 
         df(&mut state.x_df, x0);
 
-        let g_converged = state.x_df.norm(std::f64::INFINITY) < self.g_atol;
+        let g_converged = state.x_df.norm(f64::INFINITY) < self.g_atol;
         let mut converged = g_converged;
         let stopped = false;
 
@@ -299,7 +288,7 @@ mod tests {
 
         let result = optimizer.optimize(&f, &df, &x0, &ls);
 
-        assert!((result.f_x - 0.0).abs() < std::f64::EPSILON);
+        assert!((result.f_x - 0.0).abs() < f64::EPSILON);
         assert!((result.x[0] - 1.0).abs() < 1e-8);
         assert!((result.x[1] - 1.0).abs() < 1e-8);
         assert!(result.iterations <= 24);

src/optimization/first_order/mod.rs

@@ -1,6 +1,6 @@
-///
+/// Gradient descent optimization algorithm
 pub mod gradient_descent;
-///
+/// Limited-memory BFGS optimization algorithm
 pub mod lbfgs;
 
 use std::clone::Clone;
@@ -11,9 +11,9 @@ use crate::numbers::floatnum::FloatNumber;
 use crate::optimization::line_search::LineSearchMethod;
 use crate::optimization::{DF, F};
 
-///
+/// First-order optimization is a class of algorithms that use the first derivative of a function to find optimal solutions.
 pub trait FirstOrderOptimizer<T: FloatNumber> {
-    ///
+    /// run first order optimization
     fn optimize<'a, X: Array1<T>, LS: LineSearchMethod<T>>(
         &self,
         f: &F<'_, T, X>,
@@ -23,13 +23,13 @@ pub trait FirstOrderOptimizer<T: FloatNumber> {
     ) -> OptimizerResult<T, X>;
 }
 
-///
+/// Result of optimization
 #[derive(Debug, Clone)]
 pub struct OptimizerResult<T: FloatNumber, X: Array1<T>> {
-    ///
+    /// Solution
     pub x: X,
-    ///
+    /// f(x) value
     pub f_x: T,
-    ///
+    /// number of iterations
     pub iterations: usize,
 }

src/optimization/line_search.rs

@@ -1,11 +1,9 @@
-// TODO: missing documentation
-
 use crate::optimization::FunctionOrder;
 use num_traits::Float;
 
-///
+/// Line search optimization.
 pub trait LineSearchMethod<T: Float> {
-    ///
+    /// Find alpha that satisfies strong Wolfe conditions.
     fn search(
         &self,
         f: &(dyn Fn(T) -> T),
@@ -16,32 +14,31 @@ pub trait LineSearchMethod<T: Float> {
     ) -> LineSearchResult<T>;
 }
 
-///
+/// Line search result
 #[derive(Debug, Clone)]
 pub struct LineSearchResult<T: Float> {
-    ///
+    /// Alpha value
     pub alpha: T,
-    ///
+    /// f(alpha) value
     pub f_x: T,
 }
 
-///
+/// Backtracking line search method.
 pub struct Backtracking<T: Float> {
-    ///
+    /// TODO: Add documentation
     pub c1: T,
-    ///
+    /// Maximum number of iterations for Backtracking single run
     pub max_iterations: usize,
-    ///
+    /// TODO: Add documentation
     pub max_infinity_iterations: usize,
-    ///
+    /// TODO: Add documentation
     pub phi: T,
-    ///
+    /// TODO: Add documentation
     pub plo: T,
-    ///
+    /// function order
     pub order: FunctionOrder,
 }
 
-///
 impl<T: Float> Default for Backtracking<T> {
     fn default() -> Self {
         Backtracking {
@@ -55,9 +52,7 @@ impl<T: Float> Default for Backtracking<T> {
     }
 }
 
-///
 impl<T: Float> LineSearchMethod<T> for Backtracking<T> {
-    ///
     fn search(
         &self,
         f: &(dyn Fn(T) -> T),

src/optimization/mod.rs

@@ -1,21 +1,19 @@
-// TODO: missing documentation
+/// first order optimization algorithms
-
-///
 pub mod first_order;
-///
+/// line search algorithms
 pub mod line_search;
 
-///
+/// Function f(x) = y
 pub type F<'a, T, X> = dyn for<'b> Fn(&'b X) -> T + 'a;
-///
+/// Function df(x)
 pub type DF<'a, X> = dyn for<'b> Fn(&'b mut X, &'b X) + 'a;
 
-///
+/// Function order
 #[allow(clippy::upper_case_acronyms)]
 #[derive(Debug, PartialEq, Eq)]
 pub enum FunctionOrder {
-    ///
+    /// Second order
     SECOND,
-    ///
+    /// Third order
     THIRD,
 }

src/svm/mod.rs

@@ -292,7 +292,7 @@ mod tests {
             .unwrap()
             .abs();
 
-        assert!((4913f64 - result) < std::f64::EPSILON);
+        assert!((4913f64 - result).abs() < f64::EPSILON);
     }
 
     #[cfg_attr(

src/tree/decision_tree_classifier.rs

@@ -197,12 +197,12 @@ impl PartialEq for Node {
         self.output == other.output
             && self.split_feature == other.split_feature
             && match (self.split_value, other.split_value) {
-                (Some(a), Some(b)) => (a - b).abs() < std::f64::EPSILON,
+                (Some(a), Some(b)) => (a - b).abs() < f64::EPSILON,
                 (None, None) => true,
                 _ => false,
             }
             && match (self.split_score, other.split_score) {
-                (Some(a), Some(b)) => (a - b).abs() < std::f64::EPSILON,
+                (Some(a), Some(b)) => (a - b).abs() < f64::EPSILON,
                 (None, None) => true,
                 _ => false,
             }
@@ -613,7 +613,7 @@ impl<TX: Number + PartialOrd, TY: Number + Ord, X: Array2<TX>, Y: Array1<TY>>
             visitor_queue.push_back(visitor);
         }
 
-        while tree.depth() < tree.parameters().max_depth.unwrap_or(std::u16::MAX) {
+        while tree.depth() < tree.parameters().max_depth.unwrap_or(u16::MAX) {
             match visitor_queue.pop_front() {
                 Some(node) => tree.split(node, mtry, &mut visitor_queue, &mut rng),
                 None => break,
@@ -650,7 +650,7 @@ impl<TX: Number + PartialOrd, TY: Number + Ord, X: Array2<TX>, Y: Array1<TY>>
                     if node.true_child.is_none() && node.false_child.is_none() {
                         result = node.output;
                     } else if x.get((row, node.split_feature)).to_f64().unwrap()
-                        <= node.split_value.unwrap_or(std::f64::NAN)
+                        <= node.split_value.unwrap_or(f64::NAN)
                     {
                         queue.push_back(node.true_child.unwrap());
                     } else {
@@ -803,9 +803,7 @@ impl<TX: Number + PartialOrd, TY: Number + Ord, X: Array2<TX>, Y: Array1<TY>>
                     .get((i, self.nodes()[visitor.node].split_feature))
                     .to_f64()
                     .unwrap()
-                    <= self.nodes()[visitor.node]
+                    <= self.nodes()[visitor.node].split_value.unwrap_or(f64::NAN)
-                        .split_value
-                        .unwrap_or(std::f64::NAN)
                 {
                     *true_sample = visitor.samples[i];
                     tc += *true_sample;
@@ -925,14 +923,14 @@ mod tests {
     )]
     #[test]
     fn gini_impurity() {
-        assert!((impurity(&SplitCriterion::Gini, &[7, 3], 10) - 0.42).abs() < std::f64::EPSILON);
+        assert!((impurity(&SplitCriterion::Gini, &[7, 3], 10) - 0.42).abs() < f64::EPSILON);
         assert!(
             (impurity(&SplitCriterion::Entropy, &[7, 3], 10) - 0.8812908992306927).abs()
-                < std::f64::EPSILON
+                < f64::EPSILON
         );
         assert!(
             (impurity(&SplitCriterion::ClassificationError, &[7, 3], 10) - 0.3).abs()
-                < std::f64::EPSILON
+                < f64::EPSILON
         );
     }
 

src/tree/decision_tree_regressor.rs

@@ -311,15 +311,15 @@ impl Node {
 
 impl PartialEq for Node {
     fn eq(&self, other: &Self) -> bool {
-        (self.output - other.output).abs() < std::f64::EPSILON
+        (self.output - other.output).abs() < f64::EPSILON
             && self.split_feature == other.split_feature
             && match (self.split_value, other.split_value) {
-                (Some(a), Some(b)) => (a - b).abs() < std::f64::EPSILON,
+                (Some(a), Some(b)) => (a - b).abs() < f64::EPSILON,
                 (None, None) => true,
                 _ => false,
             }
             && match (self.split_score, other.split_score) {
-                (Some(a), Some(b)) => (a - b).abs() < std::f64::EPSILON,
+                (Some(a), Some(b)) => (a - b).abs() < f64::EPSILON,
                 (None, None) => true,
                 _ => false,
             }
@@ -478,7 +478,7 @@ impl<TX: Number + PartialOrd, TY: Number, X: Array2<TX>, Y: Array1<TY>>
             visitor_queue.push_back(visitor);
         }
 
-        while tree.depth() < tree.parameters().max_depth.unwrap_or(std::u16::MAX) {
+        while tree.depth() < tree.parameters().max_depth.unwrap_or(u16::MAX) {
             match visitor_queue.pop_front() {
                 Some(node) => tree.split(node, mtry, &mut visitor_queue, &mut rng),
                 None => break,
@@ -515,7 +515,7 @@ impl<TX: Number + PartialOrd, TY: Number, X: Array2<TX>, Y: Array1<TY>>
                     if node.true_child.is_none() && node.false_child.is_none() {
                         result = node.output;
                     } else if x.get((row, node.split_feature)).to_f64().unwrap()
-                        <= node.split_value.unwrap_or(std::f64::NAN)
+                        <= node.split_value.unwrap_or(f64::NAN)
                     {
                         queue.push_back(node.true_child.unwrap());
                     } else {
@@ -640,9 +640,7 @@ impl<TX: Number + PartialOrd, TY: Number, X: Array2<TX>, Y: Array1<TY>>
                     .get((i, self.nodes()[visitor.node].split_feature))
                     .to_f64()
                     .unwrap()
-                    <= self.nodes()[visitor.node]
+                    <= self.nodes()[visitor.node].split_value.unwrap_or(f64::NAN)
-                        .split_value
-                        .unwrap_or(std::f64::NAN)
                 {
                     *true_sample = visitor.samples[i];
                     tc += *true_sample;