Handle kernel serialization (#232)

* Handle kernel serialization
* Do not use typetag in WASM
* enable tests for serialization
* Update serde feature deps

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

Cargo.toml

@@ -2,7 +2,7 @@
 name = "smartcore"
 description = "Machine Learning in Rust."
 homepage = "https://smartcorelib.org"
-version = "0.3.1"
+version = "0.3.0"
 authors = ["smartcore Developers"]
 edition = "2021"
 license = "Apache-2.0"
@@ -42,13 +42,13 @@ std_rand = ["rand/std_rng", "rand/std"]
 js = ["getrandom/js"]
 
 [target.'cfg(target_arch = "wasm32")'.dependencies]
-getrandom = { version = "0.2.8", optional = true }
+getrandom = { version = "*", optional = true }
 
 [target.'cfg(all(target_arch = "wasm32", not(target_os = "wasi")))'.dev-dependencies]
 wasm-bindgen-test = "0.3"
 
 [dev-dependencies]
-itertools = "0.10.5"
+itertools = "*"
 serde_json = "1.0"
 bincode = "1.3.1"
 

README.md

@@ -18,4 +18,4 @@
 -----
 [![CI](https://github.com/smartcorelib/smartcore/actions/workflows/ci.yml/badge.svg)](https://github.com/smartcorelib/smartcore/actions/workflows/ci.yml)
 
-To start getting familiar with the new smartcore v0.3 API, there is now available a [**Jupyter Notebook environment repository**](https://github.com/smartcorelib/smartcore-jupyter). Please see instructions there, contributions welcome see [CONTRIBUTING](.github/CONTRIBUTING.md).
+To start getting familiar with the new smartcore v0.5 API, there is now available a [**Jupyter Notebook environment repository**](https://github.com/smartcorelib/smartcore-jupyter). Please see instructions there, contributions welcome see [CONTRIBUTING](.github/CONTRIBUTING.md).

smartcore.iml

@@ -0,0 +1,15 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<module type="RUST_MODULE" version="4">
+  <component name="NewModuleRootManager" inherit-compiler-output="true">
+    <exclude-output />
+    <content url="file://$MODULE_DIR$">
+      <sourceFolder url="file://$MODULE_DIR$/src" isTestSource="false" />
+      <sourceFolder url="file://$MODULE_DIR$/examples" isTestSource="false" />
+      <sourceFolder url="file://$MODULE_DIR$/tests" isTestSource="true" />
+      <sourceFolder url="file://$MODULE_DIR$/benches" isTestSource="true" />
+      <excludeFolder url="file://$MODULE_DIR$/target" />
+    </content>
+    <orderEntry type="inheritedJdk" />
+    <orderEntry type="sourceFolder" forTests="false" />
+  </component>
+</module>

src/algorithm/neighbour/fastpair.rs

@@ -260,8 +260,8 @@ mod tests_fastpair {
         let distances = fastpair.distances;
         let neighbours = fastpair.neighbours;
 
-        assert!(!distances.is_empty());
+        assert!(distances.len() != 0);
-        assert!(!neighbours.is_empty());
+        assert!(neighbours.len() != 0);
 
         assert_eq!(10, neighbours.len());
         assert_eq!(10, distances.len());
@@ -276,14 +276,18 @@ mod tests_fastpair {
         // We expect an error when we run `FastPair` on this dataset,
         // becuase `FastPair` currently only works on a minimum of 3
         // points.
-        let fastpair = FastPair::new(&dataset);
+        let _fastpair = FastPair::new(&dataset);
-        assert!(fastpair.is_err());
 
-        if let Err(e) = fastpair {
+        match _fastpair {
+            Err(e) => {
                 let expected_error =
                     Failed::because(FailedError::FindFailed, "min number of rows should be 3");
                 assert_eq!(e, expected_error)
             }
+            _ => {
+                assert!(false);
+            }
+        }
     }
 
     #[test]
@@ -578,7 +582,7 @@ mod tests_fastpair {
         };
         for p in dissimilarities.iter() {
             if p.distance.unwrap() < min_dissimilarity.distance.unwrap() {
-                min_dissimilarity = *p
+                min_dissimilarity = p.clone()
             }
         }
 

src/algorithm/neighbour/mod.rs

@@ -49,15 +49,20 @@ pub mod linear_search;
 /// Both, KNN classifier and regressor benefits from underlying search algorithms that helps to speed up queries.
 /// `KNNAlgorithmName` maintains a list of supported search algorithms, see [KNN algorithms](../algorithm/neighbour/index.html)
 #[cfg_attr(feature = "serde", derive(Serialize, Deserialize))]
-#[derive(Debug, Clone, Default)]
+#[derive(Debug, Clone)]
 pub enum KNNAlgorithmName {
     /// Heap Search algorithm, see [`LinearSearch`](../algorithm/neighbour/linear_search/index.html)
     LinearSearch,
     /// Cover Tree Search algorithm, see [`CoverTree`](../algorithm/neighbour/cover_tree/index.html)
-    #[default]
     CoverTree,
 }
 
+impl Default for KNNAlgorithmName {
+    fn default() -> Self {
+        KNNAlgorithmName::CoverTree
+    }
+}
+
 #[cfg_attr(feature = "serde", derive(Serialize, Deserialize))]
 #[derive(Debug)]
 pub(crate) enum KNNAlgorithm<T: Number, D: Distance<Vec<T>>> {

src/cluster/dbscan.rs

@@ -18,7 +18,7 @@
 //!
 //! Example:
 //!
-//! ```ignore
+//! ```
 //! use smartcore::linalg::basic::matrix::DenseMatrix;
 //! use smartcore::linalg::basic::arrays::Array2;
 //! use smartcore::cluster::dbscan::*;
@@ -511,6 +511,6 @@ mod tests {
             .and_then(|dbscan| dbscan.predict(&x))
             .unwrap();
 
-        println!("{labels:?}");
+        println!("{:?}", labels);
     }
 }

src/cluster/kmeans.rs

@@ -498,8 +498,8 @@ mod tests {
 
         let y: Vec<usize> = kmeans.predict(&x).unwrap();
 
-        for (i, _y_i) in y.iter().enumerate() {
+        for i in 0..y.len() {
-            assert_eq!({ y[i] }, kmeans._y[i]);
+            assert_eq!(y[i] as usize, kmeans._y[i]);
         }
     }
 

src/dataset/boston.rs

@@ -31,7 +31,7 @@ use crate::dataset::Dataset;
 pub fn load_dataset() -> Dataset<f32, f32> {
     let (x, y, num_samples, num_features) = match deserialize_data(std::include_bytes!("boston.xy"))
     {
-        Err(why) => panic!("Can't deserialize boston.xy. {why}"),
+        Err(why) => panic!("Can't deserialize boston.xy. {}", why),
         Ok((x, y, num_samples, num_features)) => (x, y, num_samples, num_features),
     };
 

src/dataset/breast_cancer.rs

@@ -33,7 +33,7 @@ use crate::dataset::Dataset;
 pub fn load_dataset() -> Dataset<f32, u32> {
     let (x, y, num_samples, num_features) =
         match deserialize_data(std::include_bytes!("breast_cancer.xy")) {
-            Err(why) => panic!("Can't deserialize breast_cancer.xy. {why}"),
+            Err(why) => panic!("Can't deserialize breast_cancer.xy. {}", why),
             Ok((x, y, num_samples, num_features)) => (
                 x,
                 y.into_iter().map(|x| x as u32).collect(),

src/dataset/diabetes.rs

@@ -26,7 +26,7 @@ use crate::dataset::Dataset;
 pub fn load_dataset() -> Dataset<f32, u32> {
     let (x, y, num_samples, num_features) =
         match deserialize_data(std::include_bytes!("diabetes.xy")) {
-            Err(why) => panic!("Can't deserialize diabetes.xy. {why}"),
+            Err(why) => panic!("Can't deserialize diabetes.xy. {}", why),
             Ok((x, y, num_samples, num_features)) => (
                 x,
                 y.into_iter().map(|x| x as u32).collect(),

src/dataset/digits.rs

@@ -16,7 +16,7 @@ use crate::dataset::Dataset;
 pub fn load_dataset() -> Dataset<f32, f32> {
     let (x, y, num_samples, num_features) = match deserialize_data(std::include_bytes!("digits.xy"))
     {
-        Err(why) => panic!("Can't deserialize digits.xy. {why}"),
+        Err(why) => panic!("Can't deserialize digits.xy. {}", why),
         Ok((x, y, num_samples, num_features)) => (x, y, num_samples, num_features),
     };
 

src/dataset/iris.rs

@@ -22,7 +22,7 @@ use crate::dataset::Dataset;
 pub fn load_dataset() -> Dataset<f32, u32> {
     let (x, y, num_samples, num_features): (Vec<f32>, Vec<u32>, usize, usize) =
         match deserialize_data(std::include_bytes!("iris.xy")) {
-            Err(why) => panic!("Can't deserialize iris.xy. {why}"),
+            Err(why) => panic!("Can't deserialize iris.xy. {}", why),
             Ok((x, y, num_samples, num_features)) => (
                 x,
                 y.into_iter().map(|x| x as u32).collect(),

src/dataset/mod.rs

@@ -78,7 +78,7 @@ pub(crate) fn serialize_data<X: Number + RealNumber, Y: RealNumber>(
                 .collect();
             file.write_all(&y)?;
         }
-        Err(why) => panic!("couldn't create {filename}: {why}"),
+        Err(why) => panic!("couldn't create {}: {}", filename, why),
     }
     Ok(())
 }

src/decomposition/pca.rs

@@ -231,7 +231,8 @@ impl<T: Number + RealNumber, X: Array2<T> + SVDDecomposable<T> + EVDDecomposable
 
         if parameters.n_components > n {
             return Err(Failed::fit(&format!(
-                "Number of components, n_components should be <= number of attributes ({n})"
+                "Number of components, n_components should be <= number of attributes ({})",
+                n
             )));
         }
 
@@ -373,20 +374,21 @@ mod tests {
         let parameters = PCASearchParameters {
             n_components: vec![2, 4],
             use_correlation_matrix: vec![true, false],
+            ..Default::default()
         };
         let mut iter = parameters.into_iter();
         let next = iter.next().unwrap();
         assert_eq!(next.n_components, 2);
-        assert!(next.use_correlation_matrix);
+        assert_eq!(next.use_correlation_matrix, true);
         let next = iter.next().unwrap();
         assert_eq!(next.n_components, 4);
-        assert!(next.use_correlation_matrix);
+        assert_eq!(next.use_correlation_matrix, true);
         let next = iter.next().unwrap();
         assert_eq!(next.n_components, 2);
-        assert!(!next.use_correlation_matrix);
+        assert_eq!(next.use_correlation_matrix, false);
         let next = iter.next().unwrap();
         assert_eq!(next.n_components, 4);
-        assert!(!next.use_correlation_matrix);
+        assert_eq!(next.use_correlation_matrix, false);
         assert!(iter.next().is_none());
     }
 
@@ -570,8 +572,8 @@ mod tests {
             epsilon = 1e-4
         ));
 
-        for (i, pca_eigenvalues_i) in pca.eigenvalues.iter().enumerate() {
+        for i in 0..pca.eigenvalues.len() {
-            assert!((pca_eigenvalues_i.abs() - expected_eigenvalues[i].abs()).abs() < 1e-8);
+            assert!((pca.eigenvalues[i].abs() - expected_eigenvalues[i].abs()).abs() < 1e-8);
         }
 
         let us_arrests_t = pca.transform(&us_arrests).unwrap();
@@ -692,8 +694,8 @@ mod tests {
             epsilon = 1e-4
         ));
 
-        for (i, pca_eigenvalues_i) in pca.eigenvalues.iter().enumerate() {
+        for i in 0..pca.eigenvalues.len() {
-            assert!((pca_eigenvalues_i.abs() - expected_eigenvalues[i].abs()).abs() < 1e-8);
+            assert!((pca.eigenvalues[i].abs() - expected_eigenvalues[i].abs()).abs() < 1e-8);
         }
 
         let us_arrests_t = pca.transform(&us_arrests).unwrap();

src/decomposition/svd.rs

@@ -180,7 +180,8 @@ impl<T: Number + RealNumber, X: Array2<T> + SVDDecomposable<T> + EVDDecomposable
 
         if parameters.n_components >= p {
             return Err(Failed::fit(&format!(
-                "Number of components, n_components should be < number of attributes ({p})"
+                "Number of components, n_components should be < number of attributes ({})",
+                p
             )));
         }
 
@@ -201,7 +202,8 @@ impl<T: Number + RealNumber, X: Array2<T> + SVDDecomposable<T> + EVDDecomposable
         let (p_c, k) = self.components.shape();
         if p_c != p {
             return Err(Failed::transform(&format!(
-                "Can not transform a {n}x{p} matrix into {n}x{k} matrix, incorrect input dimentions"
+                "Can not transform a {}x{} matrix into {}x{} matrix, incorrect input dimentions",
+                n, p, n, k
             )));
         }
 
@@ -225,6 +227,7 @@ mod tests {
     fn search_parameters() {
         let parameters = SVDSearchParameters {
             n_components: vec![10, 100],
+            ..Default::default()
         };
         let mut iter = parameters.into_iter();
         let next = iter.next().unwrap();

src/ensemble/random_forest_classifier.rs

@@ -454,12 +454,8 @@ impl<TX: FloatNumber + PartialOrd, TY: Number + Ord, X: Array2<TX>, Y: Array1<TY
         y: &Y,
         parameters: RandomForestClassifierParameters,
     ) -> Result<RandomForestClassifier<TX, TY, X, Y>, Failed> {
-        let (x_nrows, num_attributes) = x.shape();
+        let (_, num_attributes) = x.shape();
         let y_ncols = y.shape();
-        if x_nrows != y_ncols {
-            return Err(Failed::fit("Number of rows in X should = len(y)"));
-        }
-
         let mut yi: Vec<usize> = vec![0; y_ncols];
         let classes = y.unique();
 
@@ -682,30 +678,6 @@ mod tests {
         assert!(accuracy(&y, &classifier.predict(&x).unwrap()) >= 0.95);
     }
 
-    #[test]
-    fn test_random_matrix_with_wrong_rownum() {
-        let x_rand: DenseMatrix<f64> = DenseMatrix::<f64>::rand(21, 200);
-
-        let y: Vec<u32> = vec![0, 0, 0, 0, 0, 0, 0, 0, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1];
-
-        let fail = RandomForestClassifier::fit(
-            &x_rand,
-            &y,
-            RandomForestClassifierParameters {
-                criterion: SplitCriterion::Gini,
-                max_depth: Option::None,
-                min_samples_leaf: 1,
-                min_samples_split: 2,
-                n_trees: 100,
-                m: Option::None,
-                keep_samples: false,
-                seed: 87,
-            },
-        );
-
-        assert!(fail.is_err());
-    }
-
     #[cfg_attr(
         all(target_arch = "wasm32", not(target_os = "wasi")),
         wasm_bindgen_test::wasm_bindgen_test

src/ensemble/random_forest_regressor.rs

@@ -399,10 +399,6 @@ impl<TX: Number + FloatNumber + PartialOrd, TY: Number, X: Array2<TX>, Y: Array1
     ) -> Result<RandomForestRegressor<TX, TY, X, Y>, Failed> {
         let (n_rows, num_attributes) = x.shape();
 
-        if n_rows != y.shape() {
-            return Err(Failed::fit("Number of rows in X should = len(y)"));
-        }
-
         let mtry = parameters
             .m
             .unwrap_or((num_attributes as f64).sqrt().floor() as usize);
@@ -599,32 +595,6 @@ mod tests {
         assert!(mean_absolute_error(&y, &y_hat) < 1.0);
     }
 
-    #[test]
-    fn test_random_matrix_with_wrong_rownum() {
-        let x_rand: DenseMatrix<f64> = DenseMatrix::<f64>::rand(17, 200);
-
-        let y = vec![
-            83.0, 88.5, 88.2, 89.5, 96.2, 98.1, 99.0, 100.0, 101.2, 104.6, 108.4, 110.8, 112.6,
-            114.2, 115.7, 116.9,
-        ];
-
-        let fail = RandomForestRegressor::fit(
-            &x_rand,
-            &y,
-            RandomForestRegressorParameters {
-                max_depth: Option::None,
-                min_samples_leaf: 1,
-                min_samples_split: 2,
-                n_trees: 1000,
-                m: Option::None,
-                keep_samples: false,
-                seed: 87,
-            },
-        );
-
-        assert!(fail.is_err());
-    }
-
     #[cfg_attr(
         all(target_arch = "wasm32", not(target_os = "wasi")),
         wasm_bindgen_test::wasm_bindgen_test

src/error/mod.rs

@@ -30,7 +30,7 @@ pub enum FailedError {
     DecompositionFailed,
     /// Can't solve for x
     SolutionFailed,
-    /// Error in input parameters
+    /// Erro in input
     ParametersError,
 }
 
@@ -98,7 +98,7 @@ impl fmt::Display for FailedError {
             FailedError::SolutionFailed => "Can't find solution",
             FailedError::ParametersError => "Error in input, check parameters",
         };
-        write!(f, "{failed_err_str}")
+        write!(f, "{}", failed_err_str)
     }
 }
 

src/lib.rs

@@ -3,8 +3,7 @@
     clippy::too_many_arguments,
     clippy::many_single_char_names,
     clippy::unnecessary_wraps,
-    clippy::upper_case_acronyms,
+    clippy::upper_case_acronyms
-    clippy::approx_constant
 )]
 #![warn(missing_docs)]
 #![warn(rustdoc::missing_doc_code_examples)]

src/linalg/basic/arrays.rs

@@ -548,7 +548,7 @@ pub trait ArrayView2<T: Debug + Display + Copy + Sized>: Array<T, (usize, usize)
         let (nrows, ncols) = self.shape();
         for r in 0..nrows {
             let row: Vec<T> = (0..ncols).map(|c| *self.get((r, c))).collect();
-            writeln!(f, "{row:?}")?
+            writeln!(f, "{:?}", row)?
         }
         Ok(())
     }
@@ -918,7 +918,8 @@ pub trait Array1<T: Debug + Display + Copy + Sized>: MutArrayView1<T> + Sized +
         let len = self.shape();
         assert!(
             index.iter().all(|&i| i < len),
-            "All indices in `take` should be < {len}"
+            "All indices in `take` should be < {}",
+            len
         );
         Self::from_iterator(index.iter().map(move |&i| *self.get(i)), index.len())
     }
@@ -989,7 +990,10 @@ pub trait Array1<T: Debug + Display + Copy + Sized>: MutArrayView1<T> + Sized +
         };
         assert!(
             d1 == len,
-            "Can not multiply {nrows}x{ncols} matrix by {len} vector"
+            "Can not multiply {}x{} matrix by {} vector",
+            nrows,
+            ncols,
+            len
         );
         let mut result = Self::zeros(d2);
         for i in 0..d2 {
@@ -1107,7 +1111,11 @@ pub trait Array2<T: Debug + Display + Copy + Sized>: MutArrayView2<T> + Sized +
 
         assert!(
             nrows * ncols == onrows * oncols,
-            "Can't reshape {onrows}x{oncols} array into a {nrows}x{ncols} array"
+            "Can't reshape {}x{} array into a {}x{} array",
+            onrows,
+            oncols,
+            nrows,
+            ncols
         );
 
         Self::from_iterator(self.iterator(0).cloned(), nrows, ncols, axis)
@@ -1121,7 +1129,11 @@ pub trait Array2<T: Debug + Display + Copy + Sized>: MutArrayView2<T> + Sized +
         let (o_nrows, o_ncols) = other.shape();
         assert!(
             ncols == o_nrows,
-            "Can't multiply {nrows}x{ncols} and {o_nrows}x{o_ncols} matrices"
+            "Can't multiply {}x{} and {}x{} matrices",
+            nrows,
+            ncols,
+            o_nrows,
+            o_ncols
         );
         let inner_d = ncols;
         let mut result = Self::zeros(nrows, o_ncols);
@@ -1154,7 +1166,7 @@ pub trait Array2<T: Debug + Display + Copy + Sized>: MutArrayView2<T> + Sized +
                 _ => (nrows, ncols, o_nrows, o_ncols),
             };
             if d1 != d4 {
-                panic!("Can not multiply {d2}x{d1} by {d4}x{d3} matrices");
+                panic!("Can not multiply {}x{} by {}x{} matrices", d2, d1, d4, d3);
             }
             let mut result = Self::zeros(d2, d3);
             for r in 0..d2 {
@@ -1186,7 +1198,10 @@ pub trait Array2<T: Debug + Display + Copy + Sized>: MutArrayView2<T> + Sized +
         };
         assert!(
             d2 == len,
-            "Can not multiply {nrows}x{ncols} matrix by {len} vector"
+            "Can not multiply {}x{} matrix by {} vector",
+            nrows,
+            ncols,
+            len
         );
         let mut result = Self::zeros(d1, 1);
         for i in 0..d1 {
@@ -1417,7 +1432,8 @@ pub trait Array2<T: Debug + Display + Copy + Sized>: MutArrayView2<T> + Sized +
             0 => {
                 assert!(
                     index.iter().all(|&i| i < nrows),
-                    "All indices in `take` should be < {nrows}"
+                    "All indices in `take` should be < {}",
+                    nrows
                 );
                 Self::from_iterator(
                     index
@@ -1432,7 +1448,8 @@ pub trait Array2<T: Debug + Display + Copy + Sized>: MutArrayView2<T> + Sized +
             _ => {
                 assert!(
                     index.iter().all(|&i| i < ncols),
-                    "All indices in `take` should be < {ncols}"
+                    "All indices in `take` should be < {}",
+                    ncols
                 );
                 Self::from_iterator(
                     (0..nrows)
@@ -1719,7 +1736,7 @@ mod tests {
         let r = Vec::<f32>::rand(4);
         assert!(r.iterator(0).all(|&e| e <= 1f32));
         assert!(r.iterator(0).all(|&e| e >= 0f32));
-        assert!(r.iterator(0).copied().sum::<f32>() > 0f32);
+        assert!(r.iterator(0).map(|v| *v).sum::<f32>() > 0f32);
     }
 
     #[test]
@@ -1937,7 +1954,7 @@ mod tests {
             DenseMatrix::from_2d_array(&[&[1, 3], &[2, 4]])
         );
         assert_eq!(
-            DenseMatrix::concatenate_2d(&[&a, &b], 0),
+            DenseMatrix::concatenate_2d(&[&a.clone(), &b.clone()], 0),
             DenseMatrix::from_2d_array(&[&[1, 2], &[3, 4], &[5, 6], &[7, 8]])
         );
         assert_eq!(
@@ -2008,7 +2025,7 @@ mod tests {
         let r = DenseMatrix::<f32>::rand(2, 2);
         assert!(r.iterator(0).all(|&e| e <= 1f32));
         assert!(r.iterator(0).all(|&e| e >= 0f32));
-        assert!(r.iterator(0).copied().sum::<f32>() > 0f32);
+        assert!(r.iterator(0).map(|v| *v).sum::<f32>() > 0f32);
     }
 
     #[test]

src/linalg/basic/matrix.rs

@@ -581,9 +581,9 @@ mod tests {
             vec![4, 5, 6],
             DenseMatrix::from_slice(&(*x.slice(1..2, 0..3))).values
         );
-        let second_row: Vec<i32> = x.slice(1..2, 0..3).iterator(0).copied().collect();
+        let second_row: Vec<i32> = x.slice(1..2, 0..3).iterator(0).map(|x| *x).collect();
         assert_eq!(vec![4, 5, 6], second_row);
-        let second_col: Vec<i32> = x.slice(0..3, 1..2).iterator(0).copied().collect();
+        let second_col: Vec<i32> = x.slice(0..3, 1..2).iterator(0).map(|x| *x).collect();
         assert_eq!(vec![2, 5, 8], second_col);
     }
 
@@ -640,12 +640,12 @@ mod tests {
         let x = DenseMatrix::<&str>::from_2d_array(&[&["1", "2", "3"], &["4", "5", "6"]]);
 
         assert_eq!(vec!["1", "4", "2", "5", "3", "6"], x.values);
-        assert!(x.column_major);
+        assert!(x.column_major == true);
 
         // transpose
         let x = x.transpose();
         assert_eq!(vec!["1", "4", "2", "5", "3", "6"], x.values);
-        assert!(!x.column_major); // should change column_major
+        assert!(x.column_major == false); // should change column_major
     }
 
     #[test]
@@ -659,7 +659,7 @@ mod tests {
             vec![1, 2, 3, 4, 5, 6],
             m.values.iter().map(|e| **e).collect::<Vec<i32>>()
         );
-        assert!(!m.column_major);
+        assert!(m.column_major == false);
     }
 
     #[test]
@@ -667,10 +667,10 @@ mod tests {
         let a = DenseMatrix::from_2d_array(&[&[1, 2, 3], &[4, 5, 6]]);
         let b = DenseMatrix::from_2d_array(&[&[1, 2], &[3, 4], &[5, 6]]);
 
-        println!("{a}");
+        println!("{}", a);
         // take column 0 and 2
         assert_eq!(vec![1, 3, 4, 6], a.take(&[0, 2], 1).values);
-        println!("{b}");
+        println!("{}", b);
         // take rows 0 and 2
         assert_eq!(vec![1, 2, 5, 6], b.take(&[0, 2], 0).values);
     }
@@ -692,11 +692,11 @@ mod tests {
 
         let a = a.reshape(2, 6, 0);
         assert_eq!(vec![1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12], a.values);
-        assert!(a.ncols == 6 && a.nrows == 2 && !a.column_major);
+        assert!(a.ncols == 6 && a.nrows == 2 && a.column_major == false);
 
         let a = a.reshape(3, 4, 1);
         assert_eq!(vec![1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12], a.values);
-        assert!(a.ncols == 4 && a.nrows == 3 && a.column_major);
+        assert!(a.ncols == 4 && a.nrows == 3 && a.column_major == true);
     }
 
     #[test]

src/linalg/basic/vector.rs

@@ -160,8 +160,8 @@ mod tests {
     fn dot_product<T: Number, V: Array1<T>>(v: &V) -> T {
         let vv = V::zeros(10);
         let v_s = vv.slice(0..3);
-
+        let dot = v_s.dot(v);
-        v_s.dot(v)
+        dot
     }
 
     fn vector_ops<T: Number + PartialOrd, V: Array1<T>>(_: &V) -> T {
@@ -216,7 +216,7 @@ mod tests {
     #[test]
     fn test_mut_iterator() {
         let mut x = vec![1, 2, 3];
-        x.iterator_mut(0).for_each(|v| *v *= 2);
+        x.iterator_mut(0).for_each(|v| *v = *v * 2);
         assert_eq!(vec![2, 4, 6], x);
     }
 

src/linalg/ndarray/matrix.rs

@@ -217,7 +217,7 @@ mod tests {
     fn test_iterator() {
         let a = arr2(&[[1, 2, 3], [4, 5, 6]]);
 
-        let v: Vec<i32> = a.iterator(0).copied().collect();
+        let v: Vec<i32> = a.iterator(0).map(|&v| v).collect();
         assert_eq!(v, vec!(1, 2, 3, 4, 5, 6));
     }
 
@@ -236,7 +236,7 @@ mod tests {
         let x = arr2(&[[1, 2, 3], [4, 5, 6]]);
         let x_slice = Array2::slice(&x, 0..2, 1..2);
         assert_eq!((2, 1), x_slice.shape());
-        let v: Vec<i32> = x_slice.iterator(0).copied().collect();
+        let v: Vec<i32> = x_slice.iterator(0).map(|&v| v).collect();
         assert_eq!(v, [2, 5]);
     }
 
@@ -245,11 +245,11 @@ mod tests {
         let x = arr2(&[[1, 2, 3], [4, 5, 6]]);
         let x_slice = Array2::slice(&x, 0..2, 0..3);
         assert_eq!(
-            x_slice.iterator(0).copied().collect::<Vec<i32>>(),
+            x_slice.iterator(0).map(|&v| v).collect::<Vec<i32>>(),
             vec![1, 2, 3, 4, 5, 6]
         );
         assert_eq!(
-            x_slice.iterator(1).copied().collect::<Vec<i32>>(),
+            x_slice.iterator(1).map(|&v| v).collect::<Vec<i32>>(),
             vec![1, 4, 2, 5, 3, 6]
         );
     }
@@ -279,8 +279,8 @@ mod tests {
     fn test_c_from_iterator() {
         let data = vec![1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12];
         let a: NDArray2<i32> = Array2::from_iterator(data.clone().into_iter(), 4, 3, 0);
-        println!("{a}");
+        println!("{}", a);
         let a: NDArray2<i32> = Array2::from_iterator(data.into_iter(), 4, 3, 1);
-        println!("{a}");
+        println!("{}", a);
     }
 }

src/linalg/ndarray/vector.rs

@@ -152,7 +152,7 @@ mod tests {
     fn test_iterator() {
         let a = arr1(&[1, 2, 3]);
 
-        let v: Vec<i32> = a.iterator(0).copied().collect();
+        let v: Vec<i32> = a.iterator(0).map(|&v| v).collect();
         assert_eq!(v, vec!(1, 2, 3));
     }
 

src/linalg/traits/evd.rs

@@ -66,7 +66,7 @@ pub trait EVDDecomposable<T: Number + RealNumber>: Array2<T> {
     fn evd_mut(mut self, symmetric: bool) -> Result<EVD<T, Self>, Failed> {
         let (nrows, ncols) = self.shape();
         if ncols != nrows {
-            panic!("Matrix is not square: {nrows} x {ncols}");
+            panic!("Matrix is not square: {} x {}", nrows, ncols);
         }
 
         let n = nrows;
@@ -837,8 +837,10 @@ mod tests {
             evd.V.abs(),
             epsilon = 1e-4
         ));
-        for (i, eigen_values_i) in eigen_values.iter().enumerate() {
+        for i in 0..eigen_values.len() {
-            assert!((eigen_values_i - evd.d[i]).abs() < 1e-4);
+            assert!((eigen_values[i] - evd.d[i]).abs() < 1e-4);
+        }
+        for i in 0..eigen_values.len() {
             assert!((0f64 - evd.e[i]).abs() < std::f64::EPSILON);
         }
     }
@@ -869,8 +871,10 @@ mod tests {
             evd.V.abs(),
             epsilon = 1e-4
         ));
-        for (i, eigen_values_i) in eigen_values.iter().enumerate() {
+        for i in 0..eigen_values.len() {
-            assert!((eigen_values_i - evd.d[i]).abs() < 1e-4);
+            assert!((eigen_values[i] - evd.d[i]).abs() < 1e-4);
+        }
+        for i in 0..eigen_values.len() {
             assert!((0f64 - evd.e[i]).abs() < std::f64::EPSILON);
         }
     }
@@ -904,11 +908,11 @@ mod tests {
             evd.V.abs(),
             epsilon = 1e-4
         ));
-        for (i, eigen_values_d_i) in eigen_values_d.iter().enumerate() {
+        for i in 0..eigen_values_d.len() {
-            assert!((eigen_values_d_i - evd.d[i]).abs() < 1e-4);
+            assert!((eigen_values_d[i] - evd.d[i]).abs() < 1e-4);
         }
-        for (i, eigen_values_e_i) in eigen_values_e.iter().enumerate() {
+        for i in 0..eigen_values_e.len() {
-            assert!((eigen_values_e_i - evd.e[i]).abs() < 1e-4);
+            assert!((eigen_values_e[i] - evd.e[i]).abs() < 1e-4);
         }
     }
 }

src/linalg/traits/lu.rs

@@ -126,7 +126,7 @@ impl<T: Number + RealNumber, M: Array2<T>> LU<T, M> {
         let (m, n) = self.LU.shape();
 
         if m != n {
-            panic!("Matrix is not square: {m}x{n}");
+            panic!("Matrix is not square: {}x{}", m, n);
         }
 
         let mut inv = M::zeros(n, n);
@@ -143,7 +143,10 @@ impl<T: Number + RealNumber, M: Array2<T>> LU<T, M> {
         let (b_m, b_n) = b.shape();
 
         if b_m != m {
-            panic!("Row dimensions do not agree: A is {m} x {n}, but B is {b_m} x {b_n}");
+            panic!(
+                "Row dimensions do not agree: A is {} x {}, but B is {} x {}",
+                m, n, b_m, b_n
+            );
         }
 
         if self.singular {

src/linalg/traits/qr.rs

@@ -102,7 +102,10 @@ impl<T: Number + RealNumber, M: Array2<T>> QR<T, M> {
         let (b_nrows, b_ncols) = b.shape();
 
         if b_nrows != m {
-            panic!("Row dimensions do not agree: A is {m} x {n}, but B is {b_nrows} x {b_ncols}");
+            panic!(
+                "Row dimensions do not agree: A is {} x {}, but B is {} x {}",
+                m, n, b_nrows, b_ncols
+            );
         }
 
         if self.singular {

src/linalg/traits/stats.rs

@@ -286,7 +286,7 @@ mod tests {
         }
 
         {
-            let mut m = m;
+            let mut m = m.clone();
             m.standard_scale_mut(&m.mean(1), &m.std(1), 1);
             assert_eq!(&m, &expected_1);
         }

src/linalg/traits/svd.rs

@@ -509,8 +509,8 @@ mod tests {
 
         assert!(relative_eq!(V.abs(), svd.V.abs(), epsilon = 1e-4));
         assert!(relative_eq!(U.abs(), svd.U.abs(), epsilon = 1e-4));
-        for (i, s_i) in s.iter().enumerate() {
+        for i in 0..s.len() {
-            assert!((s_i - svd.s[i]).abs() < 1e-4);
+            assert!((s[i] - svd.s[i]).abs() < 1e-4);
         }
     }
     #[cfg_attr(
@@ -713,8 +713,8 @@ mod tests {
 
         assert!(relative_eq!(V.abs(), svd.V.abs(), epsilon = 1e-4));
         assert!(relative_eq!(U.abs(), svd.U.abs(), epsilon = 1e-4));
-        for (i, s_i) in s.iter().enumerate() {
+        for i in 0..s.len() {
-            assert!((s_i - svd.s[i]).abs() < 1e-4);
+            assert!((s[i] - svd.s[i]).abs() < 1e-4);
         }
     }
     #[cfg_attr(

src/linear/elastic_net.rs

@@ -425,7 +425,10 @@ impl<TX: FloatNumber + RealNumber, TY: Number, X: Array2<TX>, Y: Array1<TY>>
 
         for (i, col_std_i) in col_std.iter().enumerate() {
             if (*col_std_i - TX::zero()).abs() < TX::epsilon() {
-                return Err(Failed::fit(&format!("Cannot rescale constant column {i}")));
+                return Err(Failed::fit(&format!(
+                    "Cannot rescale constant column {}",
+                    i
+                )));
             }
         }
 

src/linear/lasso.rs

@@ -356,7 +356,10 @@ impl<TX: FloatNumber + RealNumber, TY: Number, X: Array2<TX>, Y: Array1<TY>> Las
 
         for (i, col_std_i) in col_std.iter().enumerate() {
             if (*col_std_i - TX::zero()).abs() < TX::epsilon() {
-                return Err(Failed::fit(&format!("Cannot rescale constant column {i}")));
+                return Err(Failed::fit(&format!(
+                    "Cannot rescale constant column {}",
+                    i
+                )));
             }
         }
 

src/linear/logistic_regression.rs

@@ -71,14 +71,19 @@ use crate::optimization::line_search::Backtracking;
 use crate::optimization::FunctionOrder;
 
 #[cfg_attr(feature = "serde", derive(Serialize, Deserialize))]
-#[derive(Debug, Clone, Eq, PartialEq, Default)]
+#[derive(Debug, Clone, Eq, PartialEq)]
 /// Solver options for Logistic regression. Right now only LBFGS solver is supported.
 pub enum LogisticRegressionSolverName {
     /// Limited-memory Broyden–Fletcher–Goldfarb–Shanno method, see [LBFGS paper](http://users.iems.northwestern.edu/~nocedal/lbfgsb.html)
-    #[default]
     LBFGS,
 }
 
+impl Default for LogisticRegressionSolverName {
+    fn default() -> Self {
+        LogisticRegressionSolverName::LBFGS
+    }
+}
+
 /// Logistic Regression parameters
 #[cfg_attr(feature = "serde", derive(Serialize, Deserialize))]
 #[derive(Debug, Clone)]
@@ -444,7 +449,8 @@ impl<TX: Number + FloatNumber + RealNumber, TY: Number + Ord, X: Array2<TX>, Y:
 
         match k.cmp(&2) {
             Ordering::Less => Err(Failed::fit(&format!(
-                "incorrect number of classes: {k}. Should be >= 2."
+                "incorrect number of classes: {}. Should be >= 2.",
+                k
             ))),
             Ordering::Equal => {
                 let x0 = Vec::zeros(num_attributes + 1);
@@ -630,19 +636,19 @@ mod tests {
 
         assert!((g[0] + 33.000068218163484).abs() < std::f64::EPSILON);
 
-        let f = objective.f(&[1., 2., 3., 4., 5., 6., 7., 8., 9.]);
+        let f = objective.f(&vec![1., 2., 3., 4., 5., 6., 7., 8., 9.]);
 
         assert!((f - 408.0052230582765).abs() < std::f64::EPSILON);
 
         let objective_reg = MultiClassObjectiveFunction {
             x: &x,
-            y,
+            y: y.clone(),
             k: 3,
             alpha: 1.0,
             _phantom_t: PhantomData,
         };
 
-        let f = objective_reg.f(&[1., 2., 3., 4., 5., 6., 7., 8., 9.]);
+        let f = objective_reg.f(&vec![1., 2., 3., 4., 5., 6., 7., 8., 9.]);
         assert!((f - 487.5052).abs() < 1e-4);
 
         objective_reg.df(&mut g, &vec![1., 2., 3., 4., 5., 6., 7., 8., 9.]);
@@ -691,18 +697,18 @@ mod tests {
         assert!((g[1] - 10.239000702928523).abs() < std::f64::EPSILON);
         assert!((g[2] - 3.869294270156324).abs() < std::f64::EPSILON);
 
-        let f = objective.f(&[1., 2., 3.]);
+        let f = objective.f(&vec![1., 2., 3.]);
 
         assert!((f - 59.76994756647412).abs() < std::f64::EPSILON);
 
         let objective_reg = BinaryObjectiveFunction {
             x: &x,
-            y,
+            y: y.clone(),
             alpha: 1.0,
             _phantom_t: PhantomData,
         };
 
-        let f = objective_reg.f(&[1., 2., 3.]);
+        let f = objective_reg.f(&vec![1., 2., 3.]);
         assert!((f - 62.2699).abs() < 1e-4);
 
         objective_reg.df(&mut g, &vec![1., 2., 3.]);

src/linear/ridge_regression.rs

@@ -71,16 +71,21 @@ use crate::numbers::basenum::Number;
 use crate::numbers::realnum::RealNumber;
 
 #[cfg_attr(feature = "serde", derive(Serialize, Deserialize))]
-#[derive(Debug, Clone, Eq, PartialEq, Default)]
+#[derive(Debug, Clone, Eq, PartialEq)]
 /// Approach to use for estimation of regression coefficients. Cholesky is more efficient but SVD is more stable.
 pub enum RidgeRegressionSolverName {
     /// Cholesky decomposition, see [Cholesky](../../linalg/cholesky/index.html)
-    #[default]
     Cholesky,
     /// SVD decomposition, see [SVD](../../linalg/svd/index.html)
     SVD,
 }
 
+impl Default for RidgeRegressionSolverName {
+    fn default() -> Self {
+        RidgeRegressionSolverName::Cholesky
+    }
+}
+
 /// Ridge Regression parameters
 #[cfg_attr(feature = "serde", derive(Serialize, Deserialize))]
 #[derive(Debug, Clone)]
@@ -379,7 +384,10 @@ impl<
 
         for (i, col_std_i) in col_std.iter().enumerate() {
             if (*col_std_i - TX::zero()).abs() < TX::epsilon() {
-                return Err(Failed::fit(&format!("Cannot rescale constant column {i}")));
+                return Err(Failed::fit(&format!(
+                    "Cannot rescale constant column {}",
+                    i
+                )));
             }
         }
 

src/metrics/cluster_hcv.rs

@@ -98,8 +98,8 @@ mod tests {
         let mut scores = HCVScore::new();
         scores.compute(&v1, &v2);
 
-        assert!((0.2548 - scores.homogeneity.unwrap()).abs() < 1e-4);
+        assert!((0.2548 - scores.homogeneity.unwrap() as f64).abs() < 1e-4);
-        assert!((0.5440 - scores.completeness.unwrap()).abs() < 1e-4);
+        assert!((0.5440 - scores.completeness.unwrap() as f64).abs() < 1e-4);
-        assert!((0.3471 - scores.v_measure.unwrap()).abs() < 1e-4);
+        assert!((0.3471 - scores.v_measure.unwrap() as f64).abs() < 1e-4);
     }
 }

src/metrics/cluster_helpers.rs

@@ -125,7 +125,7 @@ mod tests {
     fn entropy_test() {
         let v1 = vec![0, 0, 1, 1, 2, 0, 4];
 
-        assert!((1.2770 - entropy(&v1).unwrap()).abs() < 1e-4);
+        assert!((1.2770 - entropy(&v1).unwrap() as f64).abs() < 1e-4);
     }
 
     #[cfg_attr(

src/metrics/f1.rs

@@ -95,8 +95,8 @@ mod tests {
         let score1: f64 = F1::new_with(beta).get_score(&y_true, &y_pred);
         let score2: f64 = F1::new_with(beta).get_score(&y_true, &y_true);
 
-        println!("{score1:?}");
+        println!("{:?}", score1);
-        println!("{score2:?}");
+        println!("{:?}", score2);
 
         assert!((score1 - 0.57142857).abs() < 1e-8);
         assert!((score2 - 1.0).abs() < 1e-8);

src/model_selection/kfold.rs

@@ -213,17 +213,17 @@ mod tests {
 
         for t in &test_masks[0][0..11] {
             // TODO: this can be prob done better
-            assert!(*t)
+            assert_eq!(*t, true)
         }
         for t in &test_masks[0][11..22] {
-            assert!(!*t)
+            assert_eq!(*t, false)
         }
 
         for t in &test_masks[1][0..11] {
-            assert!(!*t)
+            assert_eq!(*t, false)
         }
         for t in &test_masks[1][11..22] {
-            assert!(*t)
+            assert_eq!(*t, true)
         }
     }
 

src/model_selection/mod.rs

@@ -169,7 +169,7 @@ pub fn train_test_split<
     let n_test = ((n as f32) * test_size) as usize;
 
     if n_test < 1 {
-        panic!("number of sample is too small {n}");
+        panic!("number of sample is too small {}", n);
     }
 
     let mut indices: Vec<usize> = (0..n).collect();
@@ -553,6 +553,6 @@ mod tests {
             &accuracy,
         )
         .unwrap();
-        println!("{results:?}");
+        println!("{:?}", results);
     }
 }

src/naive_bayes/bernoulli.rs

@@ -271,18 +271,21 @@ impl<TY: Number + Ord + Unsigned> BernoulliNBDistribution<TY> {
         let y_samples = y.shape();
         if y_samples != n_samples {
             return Err(Failed::fit(&format!(
-                "Size of x should equal size of y; |x|=[{n_samples}], |y|=[{y_samples}]"
+                "Size of x should equal size of y; |x|=[{}], |y|=[{}]",
+                n_samples, y_samples
             )));
         }
 
         if n_samples == 0 {
             return Err(Failed::fit(&format!(
-                "Size of x and y should greater than 0; |x|=[{n_samples}]"
+                "Size of x and y should greater than 0; |x|=[{}]",
+                n_samples
             )));
         }
         if alpha < 0f64 {
             return Err(Failed::fit(&format!(
-                "Alpha should be greater than 0; |alpha|=[{alpha}]"
+                "Alpha should be greater than 0; |alpha|=[{}]",
+                alpha
             )));
         }
 
@@ -315,7 +318,8 @@ impl<TY: Number + Ord + Unsigned> BernoulliNBDistribution<TY> {
                 feature_in_class_counter[class_index][idx] +=
                     row_i.to_usize().ok_or_else(|| {
                         Failed::fit(&format!(
-                            "Elements of the matrix should be 1.0 or 0.0 |found|=[{row_i}]"
+                            "Elements of the matrix should be 1.0 or 0.0 |found|=[{}]",
+                            row_i
                         ))
                     })?;
             }

src/naive_bayes/categorical.rs

@@ -158,7 +158,8 @@ impl<T: Number + Unsigned> CategoricalNBDistribution<T> {
     pub fn fit<X: Array2<T>, Y: Array1<T>>(x: &X, y: &Y, alpha: f64) -> Result<Self, Failed> {
         if alpha < 0f64 {
             return Err(Failed::fit(&format!(
-                "alpha should be >= 0, alpha=[{alpha}]"
+                "alpha should be >= 0, alpha=[{}]",
+                alpha
             )));
         }
 
@@ -166,13 +167,15 @@ impl<T: Number + Unsigned> CategoricalNBDistribution<T> {
         let y_samples = y.shape();
         if y_samples != n_samples {
             return Err(Failed::fit(&format!(
-                "Size of x should equal size of y; |x|=[{n_samples}], |y|=[{y_samples}]"
+                "Size of x should equal size of y; |x|=[{}], |y|=[{}]",
+                n_samples, y_samples
             )));
         }
 
         if n_samples == 0 {
             return Err(Failed::fit(&format!(
-                "Size of x and y should greater than 0; |x|=[{n_samples}]"
+                "Size of x and y should greater than 0; |x|=[{}]",
+                n_samples
             )));
         }
         let y: Vec<usize> = y.iterator(0).map(|y_i| y_i.to_usize().unwrap()).collect();
@@ -199,7 +202,8 @@ impl<T: Number + Unsigned> CategoricalNBDistribution<T> {
                 .max()
                 .ok_or_else(|| {
                     Failed::fit(&format!(
-                        "Failed to get the categories for feature = {feature}"
+                        "Failed to get the categories for feature = {}",
+                        feature
                     ))
                 })?;
             n_categories.push(feature_max + 1);
@@ -425,6 +429,7 @@ mod tests {
     fn search_parameters() {
         let parameters = CategoricalNBSearchParameters {
             alpha: vec![1., 2.],
+            ..Default::default()
         };
         let mut iter = parameters.into_iter();
         let next = iter.next().unwrap();

src/naive_bayes/gaussian.rs

@@ -185,13 +185,15 @@ impl<TY: Number + Ord + Unsigned> GaussianNBDistribution<TY> {
         let y_samples = y.shape();
         if y_samples != n_samples {
             return Err(Failed::fit(&format!(
-                "Size of x should equal size of y; |x|=[{n_samples}], |y|=[{y_samples}]"
+                "Size of x should equal size of y; |x|=[{}], |y|=[{}]",
+                n_samples, y_samples
             )));
         }
 
         if n_samples == 0 {
             return Err(Failed::fit(&format!(
-                "Size of x and y should greater than 0; |x|=[{n_samples}]"
+                "Size of x and y should greater than 0; |x|=[{}]",
+                n_samples
             )));
         }
         let (class_labels, indices) = y.unique_with_indices();
@@ -373,6 +375,7 @@ mod tests {
     fn search_parameters() {
         let parameters = GaussianNBSearchParameters {
             priors: vec![Some(vec![1.]), Some(vec![2.])],
+            ..Default::default()
         };
         let mut iter = parameters.into_iter();
         let next = iter.next().unwrap();

src/naive_bayes/multinomial.rs

@@ -220,18 +220,21 @@ impl<TY: Number + Ord + Unsigned> MultinomialNBDistribution<TY> {
         let y_samples = y.shape();
         if y_samples != n_samples {
             return Err(Failed::fit(&format!(
-                "Size of x should equal size of y; |x|=[{n_samples}], |y|=[{y_samples}]"
+                "Size of x should equal size of y; |x|=[{}], |y|=[{}]",
+                n_samples, y_samples
             )));
         }
 
         if n_samples == 0 {
             return Err(Failed::fit(&format!(
-                "Size of x and y should greater than 0; |x|=[{n_samples}]"
+                "Size of x and y should greater than 0; |x|=[{}]",
+                n_samples
             )));
         }
         if alpha < 0f64 {
             return Err(Failed::fit(&format!(
-                "Alpha should be greater than 0; |alpha|=[{alpha}]"
+                "Alpha should be greater than 0; |alpha|=[{}]",
+                alpha
             )));
         }
 
@@ -263,7 +266,8 @@ impl<TY: Number + Ord + Unsigned> MultinomialNBDistribution<TY> {
                 feature_in_class_counter[class_index][idx] +=
                     row_i.to_usize().ok_or_else(|| {
                         Failed::fit(&format!(
-                            "Elements of the matrix should be convertible to usize |found|=[{row_i}]"
+                            "Elements of the matrix should be convertible to usize |found|=[{}]",
+                            row_i
                         ))
                     })?;
             }

src/neighbors/knn_classifier.rs

@@ -236,7 +236,8 @@ impl<TX: Number, TY: Number + Ord, X: Array2<TX>, Y: Array1<TY>, D: Distance<Vec
 
         if x_n != y_n {
             return Err(Failed::fit(&format!(
-                "Size of x should equal size of y; |x|=[{x_n}], |y|=[{y_n}]"
+                "Size of x should equal size of y; |x|=[{}], |y|=[{}]",
+                x_n, y_n
             )));
         }
 

src/neighbors/knn_regressor.rs

@@ -224,7 +224,8 @@ impl<TX: Number, TY: Number, X: Array2<TX>, Y: Array1<TY>, D: Distance<Vec<TX>>>
 
         if x_n != y_n {
             return Err(Failed::fit(&format!(
-                "Size of x should equal size of y; |x|=[{x_n}], |y|=[{y_n}]"
+                "Size of x should equal size of y; |x|=[{}], |y|=[{}]",
+                x_n, y_n
             )));
         }
 

src/neighbors/mod.rs

@@ -49,15 +49,20 @@ pub type KNNAlgorithmName = crate::algorithm::neighbour::KNNAlgorithmName;
 
 /// Weight function that is used to determine estimated value.
 #[cfg_attr(feature = "serde", derive(Serialize, Deserialize))]
-#[derive(Debug, Clone, Default)]
+#[derive(Debug, Clone)]
 pub enum KNNWeightFunction {
     /// All k nearest points are weighted equally
-    #[default]
     Uniform,
     /// k nearest points are weighted by the inverse of their distance. Closer neighbors will have a greater influence than neighbors which are further away.
     Distance,
 }
 
+impl Default for KNNWeightFunction {
+    fn default() -> Self {
+        KNNWeightFunction::Uniform
+    }
+}
+
 impl KNNWeightFunction {
     fn calc_weights(&self, distances: Vec<f64>) -> std::vec::Vec<f64> {
         match *self {

src/numbers/realnum.rs

@@ -2,13 +2,9 @@
 //! Most algorithms in `smartcore` rely on basic linear algebra operations like dot product, matrix decomposition and other subroutines that are defined for a set of real numbers, ℝ.
 //! This module defines real number and some useful functions that are used in [Linear Algebra](../../linalg/index.html) module.
 
-use rand::rngs::SmallRng;
-use rand::{Rng, SeedableRng};
-
 use num_traits::Float;
 
 use crate::numbers::basenum::Number;
-use crate::rand_custom::get_rng_impl;
 
 /// Defines real number
 /// <script type="text/javascript" src="https://cdnjs.cloudflare.com/ajax/libs/mathjax/2.7.0/MathJax.js?config=TeX-AMS_CHTML"></script>
@@ -67,12 +63,8 @@ impl RealNumber for f64 {
     }
 
     fn rand() -> f64 {
-        let mut small_rng = get_rng_impl(None);
+        // TODO: to be implemented, see issue smartcore#214
-
+        1.0
-        let mut rngs: Vec<SmallRng> = (0..3)
-            .map(|_| SmallRng::from_rng(&mut small_rng).unwrap())
-            .collect();
-        rngs[0].gen::<f64>()
     }
 
     fn two() -> Self {
@@ -116,12 +108,7 @@ impl RealNumber for f32 {
     }
 
     fn rand() -> f32 {
-        let mut small_rng = get_rng_impl(None);
+        1.0
-
-        let mut rngs: Vec<SmallRng> = (0..3)
-            .map(|_| SmallRng::from_rng(&mut small_rng).unwrap())
-            .collect();
-        rngs[0].gen::<f32>()
     }
 
     fn two() -> Self {
@@ -162,14 +149,4 @@ mod tests {
     fn f64_from_string() {
         assert_eq!(f64::from_str("1.111111111").unwrap(), 1.111111111)
     }
-
-    #[test]
-    fn f64_rand() {
-        f64::rand();
-    }
-
-    #[test]
-    fn f32_rand() {
-        f32::rand();
-    }
 }

src/optimization/first_order/gradient_descent.rs

@@ -113,13 +113,12 @@ mod tests {
             g[1] = 200. * (x[1] - x[0].powf(2.));
         };
 
-        let ls: Backtracking<f64> = Backtracking::<f64> {
+        let mut ls: Backtracking<f64> = Default::default();
-            order: FunctionOrder::THIRD,
+        ls.order = FunctionOrder::THIRD;
-            ..Default::default()
-        };
         let optimizer: GradientDescent = Default::default();
 
         let result = optimizer.optimize(&f, &df, &x0, &ls);
+        println!("{:?}", result);
 
         assert!((result.f_x - 0.0).abs() < 1e-5);
         assert!((result.x[0] - 1.0).abs() < 1e-2);

src/optimization/first_order/lbfgs.rs

@@ -196,9 +196,9 @@ impl LBFGS {
     }
 
     ///
-    fn update_hessian<T: FloatNumber, X: Array1<T>>(
+    fn update_hessian<'a, T: FloatNumber, X: Array1<T>>(
         &self,
-        _: &DF<'_, X>,
+        _: &'a DF<'_, X>,
         state: &mut LBFGSState<T, X>,
     ) {
         state.dg = state.x_df.sub(&state.x_df_prev);
@@ -291,10 +291,8 @@ mod tests {
             g[0] = -2. * (1. - x[0]) - 400. * (x[1] - x[0].powf(2.)) * x[0];
             g[1] = 200. * (x[1] - x[0].powf(2.));
         };
-        let ls: Backtracking<f64> = Backtracking::<f64> {
+        let mut ls: Backtracking<f64> = Default::default();
-            order: FunctionOrder::THIRD,
+        ls.order = FunctionOrder::THIRD;
-            ..Default::default()
-        };
         let optimizer: LBFGS = Default::default();
 
         let result = optimizer.optimize(&f, &df, &x0, &ls);

src/preprocessing/categorical.rs

@@ -132,7 +132,8 @@ impl OneHotEncoder {
                     data.copy_col_as_vec(idx, &mut col_buf);
                     if !validate_col_is_categorical(&col_buf) {
                         let msg = format!(
-                            "Column {idx} of data matrix containts non categorizable (integer) values"
+                            "Column {} of data matrix containts non categorizable (integer) values",
+                            idx
                         );
                         return Err(Failed::fit(&msg[..]));
                     }
@@ -181,7 +182,7 @@ impl OneHotEncoder {
                 match oh_vec {
                     None => {
                         // Since we support T types, bad value in a series causes in to be invalid
-                        let msg = format!("At least one value in column {old_cidx} doesn't conform to category definition");
+                        let msg = format!("At least one value in column {} doesn't conform to category definition", old_cidx);
                         return Err(Failed::transform(&msg[..]));
                     }
                     Some(v) => {
@@ -337,7 +338,11 @@ mod tests {
         ]);
 
         let params = OneHotEncoderParams::from_cat_idx(&[1]);
-        let result = OneHotEncoder::fit(&m, params);
+        match OneHotEncoder::fit(&m, params) {
-        assert!(result.is_err());
+            Err(_) => {
+                assert!(true);
+            }
+            _ => assert!(false),
+        }
     }
 }

src/preprocessing/numerical.rs

@@ -294,7 +294,7 @@ mod tests {
                     &[0.5708488802, 0.1846414616, 0.9590802982, 0.5591871046],
                     &[0.8387612750, 0.5754861361, 0.5537109852, 0.1077646442],
                 ]));
-            println!("{transformed_values}");
+            println!("{}", transformed_values);
             assert!(transformed_values.approximate_eq(
                 &DenseMatrix::from_2d_array(&[
                     &[-1.1154020653, -0.4031985330, 0.9284605204, -0.4271473866],

src/preprocessing/series_encoder.rs

@@ -206,7 +206,7 @@ mod tests {
     #[test]
     fn from_categories() {
         let fake_categories: Vec<usize> = vec![1, 2, 3, 4, 5, 3, 5, 3, 1, 2, 4];
-        let it = fake_categories.iter().copied();
+        let it = fake_categories.iter().map(|&a| a);
         let enc = CategoryMapper::<usize>::fit_to_iter(it);
         let oh_vec: Vec<f64> = match enc.get_one_hot(&1) {
             None => panic!("Wrong categories"),
@@ -218,8 +218,8 @@ mod tests {
 
     fn build_fake_str_enc<'a>() -> CategoryMapper<&'a str> {
         let fake_category_pos = vec!["background", "dog", "cat"];
-
+        let enc = CategoryMapper::<&str>::from_positional_category_vec(fake_category_pos);
-        CategoryMapper::<&str>::from_positional_category_vec(fake_category_pos)
+        enc
     }
     #[cfg_attr(
         all(target_arch = "wasm32", not(target_os = "wasi")),
@@ -275,7 +275,7 @@ mod tests {
         let lab = enc.invert_one_hot(res).unwrap();
         assert_eq!(lab, "dog");
         if let Err(e) = enc.invert_one_hot(vec![0.0, 0.0, 0.0]) {
-            let pos_entries = "Expected a single positive entry, 0 entires found".to_string();
+            let pos_entries = format!("Expected a single positive entry, 0 entires found");
             assert_eq!(e, Failed::transform(&pos_entries[..]));
         };
     }

src/readers/csv.rs

@@ -167,7 +167,7 @@ where
 }
 
 /// Ensure that a string containing a csv row conforms to a specified row format.
-fn validate_csv_row(row: &str, row_format: &CSVRowFormat<'_>) -> Result<(), ReadingError> {
+fn validate_csv_row<'a>(row: &'a str, row_format: &CSVRowFormat<'_>) -> Result<(), ReadingError> {
     let actual_number_of_fields = row.split(row_format.field_seperator).count();
     if row_format.n_fields == actual_number_of_fields {
         Ok(())
@@ -208,7 +208,7 @@ where
     match value_string.parse::<T>().ok() {
         Some(value) => Ok(value),
         None => Err(ReadingError::InvalidField {
-            msg: format!("Value '{value_string}' could not be read.",),
+            msg: format!("Value '{}' could not be read.", value_string,),
         }),
     }
 }

src/svm/svc.rs

@@ -983,7 +983,11 @@ mod tests {
             .unwrap();
         let acc = accuracy(&y, &(y_hat.iter().map(|e| e.to_i32().unwrap()).collect()));
 
-        assert!(acc >= 0.9, "accuracy ({acc}) is not larger or equal to 0.9");
+        assert!(
+            acc >= 0.9,
+            "accuracy ({}) is not larger or equal to 0.9",
+            acc
+        );
     }
 
     #[cfg_attr(
@@ -1072,7 +1076,11 @@ mod tests {
 
         let acc = accuracy(&y, &(y_hat.iter().map(|e| e.to_i32().unwrap()).collect()));
 
-        assert!(acc >= 0.9, "accuracy ({acc}) is not larger or equal to 0.9");
+        assert!(
+            acc >= 0.9,
+            "accuracy ({}) is not larger or equal to 0.9",
+            acc
+        );
     }
 
     #[cfg_attr(

src/svm/svr.rs

@@ -662,7 +662,7 @@ mod tests {
         .unwrap();
 
         let t = mean_squared_error(&y_hat, &y);
-        println!("{t:?}");
+        println!("{:?}", t);
         assert!(t < 2.5);
     }
 

src/tree/decision_tree_classifier.rs

@@ -137,17 +137,16 @@ impl<TX: Number + PartialOrd, TY: Number + Ord, X: Array2<TX>, Y: Array1<TY>>
         self.classes.as_ref()
     }
     /// Get depth of tree
-    pub fn depth(&self) -> u16 {
+    fn depth(&self) -> u16 {
         self.depth
     }
 }
 
 /// The function to measure the quality of a split.
 #[cfg_attr(feature = "serde", derive(Serialize, Deserialize))]
-#[derive(Debug, Clone, Default)]
+#[derive(Debug, Clone)]
 pub enum SplitCriterion {
     /// [Gini index](../decision_tree_classifier/index.html)
-    #[default]
     Gini,
     /// [Entropy](../decision_tree_classifier/index.html)
     Entropy,
@@ -155,6 +154,12 @@ pub enum SplitCriterion {
     ClassificationError,
 }
 
+impl Default for SplitCriterion {
+    fn default() -> Self {
+        SplitCriterion::Gini
+    }
+}
+
 #[cfg_attr(feature = "serde", derive(Serialize, Deserialize))]
 #[derive(Debug, Clone)]
 struct Node {
@@ -538,10 +543,6 @@ impl<TX: Number + PartialOrd, TY: Number + Ord, X: Array2<TX>, Y: Array1<TY>>
         parameters: DecisionTreeClassifierParameters,
     ) -> Result<DecisionTreeClassifier<TX, TY, X, Y>, Failed> {
         let (x_nrows, num_attributes) = x.shape();
-        if x_nrows != y.shape() {
-            return Err(Failed::fit("Size of x should equal size of y"));
-        }
-
         let samples = vec![1; x_nrows];
         DecisionTreeClassifier::fit_weak_learner(x, y, samples, num_attributes, parameters)
     }
@@ -559,7 +560,8 @@ impl<TX: Number + PartialOrd, TY: Number + Ord, X: Array2<TX>, Y: Array1<TY>>
         let k = classes.len();
         if k < 2 {
             return Err(Failed::fit(&format!(
-                "Incorrect number of classes: {k}. Should be >= 2."
+                "Incorrect number of classes: {}. Should be >= 2.",
+                k
             )));
         }
 
@@ -899,13 +901,15 @@ mod tests {
     )]
     #[test]
     fn gini_impurity() {
-        assert!((impurity(&SplitCriterion::Gini, &[7, 3], 10) - 0.42).abs() < std::f64::EPSILON);
         assert!(
-            (impurity(&SplitCriterion::Entropy, &[7, 3], 10) - 0.8812908992306927).abs()
+            (impurity(&SplitCriterion::Gini, &vec![7, 3], 10) - 0.42).abs() < std::f64::EPSILON
+        );
+        assert!(
+            (impurity(&SplitCriterion::Entropy, &vec![7, 3], 10) - 0.8812908992306927).abs()
                 < std::f64::EPSILON
         );
         assert!(
-            (impurity(&SplitCriterion::ClassificationError, &[7, 3], 10) - 0.3).abs()
+            (impurity(&SplitCriterion::ClassificationError, &vec![7, 3], 10) - 0.3).abs()
                 < std::f64::EPSILON
         );
     }
@@ -967,17 +971,6 @@ mod tests {
         );
     }
 
-    #[test]
-    fn test_random_matrix_with_wrong_rownum() {
-        let x_rand: DenseMatrix<f64> = DenseMatrix::<f64>::rand(21, 200);
-
-        let y: Vec<u32> = vec![0, 0, 0, 0, 0, 0, 0, 0, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1];
-
-        let fail = DecisionTreeClassifier::fit(&x_rand, &y, Default::default());
-
-        assert!(fail.is_err());
-    }
-
     #[cfg_attr(
         all(target_arch = "wasm32", not(target_os = "wasi")),
         wasm_bindgen_test::wasm_bindgen_test

src/tree/decision_tree_regressor.rs

@@ -18,6 +18,7 @@
 //! Example:
 //!
 //! ```
+//! use rand::thread_rng;
 //! use smartcore::linalg::basic::matrix::DenseMatrix;
 //! use smartcore::tree::decision_tree_regressor::*;
 //!
@@ -421,10 +422,6 @@ impl<TX: Number + PartialOrd, TY: Number, X: Array2<TX>, Y: Array1<TY>>
         parameters: DecisionTreeRegressorParameters,
     ) -> Result<DecisionTreeRegressor<TX, TY, X, Y>, Failed> {
         let (x_nrows, num_attributes) = x.shape();
-        if x_nrows != y.shape() {
-            return Err(Failed::fit("Size of x should equal size of y"));
-        }
-
         let samples = vec![1; x_nrows];
         DecisionTreeRegressor::fit_weak_learner(x, y, samples, num_attributes, parameters)
     }