Merge branch 'development' of github.com:smartcorelib/smartcore into mec-is/predict-probability

* handle multiclass precision/recall

Cargo.toml

@@ -33,7 +33,8 @@ itertools = "0.10.3"
 getrandom = { version = "0.2", features = ["js"] }
 
 [dev-dependencies]
-criterion = "0.3"
+smartcore = { path = ".", features = ["fp_bench"] }
+criterion = { version = "0.4", default-features = false }
 serde_json = "1.0"
 bincode = "1.3.1"
 

src/ensemble/random_forest_classifier.rs

@@ -55,7 +55,8 @@ use serde::{Deserialize, Serialize};
 
 use crate::api::{Predictor, SupervisedEstimator};
 use crate::error::{Failed, FailedError};
-use crate::linalg::Matrix;
+use crate::linalg::naive::dense_matrix::DenseMatrix;
+use crate::linalg::{BaseMatrix, Matrix};
 use crate::math::num::RealNumber;
 use crate::tree::decision_tree_classifier::{
     which_max, DecisionTreeClassifier, DecisionTreeClassifierParameters, SplitCriterion,
@@ -316,6 +317,37 @@ impl<T: RealNumber> RandomForestClassifier<T> {
         which_max(&result)
     }
 
+    /// Predict the per-class probabilties for each observation.
+    /// The probability is calculated as the fraction of trees that predicted a given class
+    pub fn predict_probs<M: Matrix<T>>(&self, x: &M) -> Result<DenseMatrix<f64>, Failed> {
+        let mut result = DenseMatrix::<f64>::zeros(x.shape().0, self.classes.len());
+
+        let (n, _) = x.shape();
+
+        for i in 0..n {
+            let row_probs = self.predict_probs_for_row(x, i);
+
+            for (j, item) in row_probs.iter().enumerate() {
+                result.set(i, j, *item);
+            }
+        }
+
+        Ok(result)
+    }
+
+    fn predict_probs_for_row<M: Matrix<T>>(&self, x: &M, row: usize) -> Vec<f64> {
+        let mut result = vec![0; self.classes.len()];
+
+        for tree in self.trees.iter() {
+            result[tree.predict_for_row(x, row)] += 1;
+        }
+
+        result
+            .iter()
+            .map(|n| *n as f64 / self.trees.len() as f64)
+            .collect()
+    }
+
     fn sample_with_replacement(y: &[usize], num_classes: usize, rng: &mut impl Rng) -> Vec<usize> {
         let class_weight = vec![1.; num_classes];
         let nrows = y.len();
@@ -341,7 +373,7 @@ impl<T: RealNumber> RandomForestClassifier<T> {
 }
 
 #[cfg(test)]
-mod tests {
+mod tests_prob {
     use super::*;
     use crate::linalg::naive::dense_matrix::DenseMatrix;
     use crate::metrics::*;
@@ -482,4 +514,69 @@ mod tests {
 
         assert_eq!(forest, deserialized_forest);
     }
+
+    #[test]
+    fn fit_predict_probabilities() {
+        let x = DenseMatrix::<f64>::from_2d_array(&[
+            &[5.1, 3.5, 1.4, 0.2],
+            &[4.9, 3.0, 1.4, 0.2],
+            &[4.7, 3.2, 1.3, 0.2],
+            &[4.6, 3.1, 1.5, 0.2],
+            &[5.0, 3.6, 1.4, 0.2],
+            &[5.4, 3.9, 1.7, 0.4],
+            &[4.6, 3.4, 1.4, 0.3],
+            &[5.0, 3.4, 1.5, 0.2],
+            &[4.4, 2.9, 1.4, 0.2],
+            &[4.9, 3.1, 1.5, 0.1],
+            &[7.0, 3.2, 4.7, 1.4],
+            &[6.4, 3.2, 4.5, 1.5],
+            &[6.9, 3.1, 4.9, 1.5],
+            &[5.5, 2.3, 4.0, 1.3],
+            &[6.5, 2.8, 4.6, 1.5],
+            &[5.7, 2.8, 4.5, 1.3],
+            &[6.3, 3.3, 4.7, 1.6],
+            &[4.9, 2.4, 3.3, 1.0],
+            &[6.6, 2.9, 4.6, 1.3],
+            &[5.2, 2.7, 3.9, 1.4],
+        ]);
+        let y = vec![
+            0., 0., 0., 0., 0., 0., 0., 0., 1., 1., 1., 1., 1., 1., 1., 1., 1., 1., 1., 1.,
+        ];
+
+        let classifier = RandomForestClassifier::fit(
+            &x,
+            &y,
+            RandomForestClassifierParameters {
+                criterion: SplitCriterion::Gini,
+                max_depth: None,
+                min_samples_leaf: 1,
+                min_samples_split: 2,
+                n_trees: 100,
+                m: Option::None,
+                keep_samples: false,
+                seed: 87,
+            },
+        )
+        .unwrap();
+
+        println!("{:?}", classifier.classes);
+
+        let results = classifier.predict_probs(&x).unwrap();
+        println!("{:?}", x.shape());
+        println!("{:?}", results);
+        println!("{:?}", results.shape());
+
+        assert_eq!(
+            results,
+            DenseMatrix::<f64>::from_array(
+                20,
+                2,
+                &[
+                    1.0, 0.0, 0.78, 0.22, 0.95, 0.05, 0.82, 0.18, 1.0, 0.0, 0.92, 0.08, 0.99, 0.01,
+                    0.96, 0.04, 0.36, 0.64, 0.33, 0.67, 0.02, 0.98, 0.02, 0.98, 0.0, 1.0, 0.0, 1.0,
+                    0.0, 1.0, 0.0, 1.0, 0.03, 0.97, 0.05, 0.95, 0.0, 1.0, 0.02, 0.98
+                ]
+            )
+        );
+    }
 }

src/math/num.rs

@@ -46,8 +46,11 @@ pub trait RealNumber:
         self * self
     }
 
-    /// Raw transmutation to u64
+    /// Raw transmutation to u32
     fn to_f32_bits(self) -> u32;
+
+    /// Raw transmutation to u64
+    fn to_f64_bits(self) -> u64;
 }
 
 impl RealNumber for f64 {
@@ -89,6 +92,10 @@ impl RealNumber for f64 {
     fn to_f32_bits(self) -> u32 {
         self.to_bits() as u32
     }
+
+    fn to_f64_bits(self) -> u64 {
+        self.to_bits()
+    }
 }
 
 impl RealNumber for f32 {
@@ -130,6 +137,10 @@ impl RealNumber for f32 {
     fn to_f32_bits(self) -> u32 {
         self.to_bits()
     }
+
+    fn to_f64_bits(self) -> u64 {
+        self.to_bits() as u64
+    }
 }
 
 #[cfg(test)]

src/metrics/precision.rs

@@ -18,6 +18,8 @@
 //!
 //! <script src="https://polyfill.io/v3/polyfill.min.js?features=es6"></script>
 //! <script id="MathJax-script" async src="https://cdn.jsdelivr.net/npm/mathjax@3/es5/tex-mml-chtml.js"></script>
+use std::collections::HashSet;
+
 #[cfg(feature = "serde")]
 use serde::{Deserialize, Serialize};
 
@@ -42,34 +44,33 @@ impl Precision {
             );
         }
 
+        let mut classes = HashSet::new();
+        for i in 0..y_true.len() {
+            classes.insert(y_true.get(i).to_f64_bits());
+        }
+        let classes = classes.len();
+
         let mut tp = 0;
-        let mut p = 0;
+        let mut fp = 0;
-        let n = y_true.len();
+        for i in 0..y_true.len() {
-        for i in 0..n {
+            if y_pred.get(i) == y_true.get(i) {
-            if y_true.get(i) != T::zero() && y_true.get(i) != T::one() {
+                if classes == 2 {
-                panic!(
+                    if y_true.get(i) == T::one() {
-                    "Precision can only be applied to binary classification: {}",
+                        tp += 1;
-                    y_true.get(i)
+                    }
-                );
+                } else {
-            }
-
-            if y_pred.get(i) != T::zero() && y_pred.get(i) != T::one() {
-                panic!(
-                    "Precision can only be applied to binary classification: {}",
-                    y_pred.get(i)
-                );
-            }
-
-            if y_pred.get(i) == T::one() {
-                p += 1;
-
-                if y_true.get(i) == T::one() {
                     tp += 1;
                 }
+            } else if classes == 2 {
+                if y_true.get(i) == T::one() {
+                    fp += 1;
+                }
+            } else {
+                fp += 1;
             }
         }
 
-        T::from_i64(tp).unwrap() / T::from_i64(p).unwrap()
+        T::from_i64(tp).unwrap() / (T::from_i64(tp).unwrap() + T::from_i64(fp).unwrap())
     }
 }
 
@@ -88,5 +89,24 @@ mod tests {
 
         assert!((score1 - 0.5).abs() < 1e-8);
         assert!((score2 - 1.0).abs() < 1e-8);
+
+        let y_pred: Vec<f64> = vec![0., 0., 1., 1., 1., 1.];
+        let y_true: Vec<f64> = vec![0., 1., 1., 0., 1., 0.];
+
+        let score3: f64 = Precision {}.get_score(&y_pred, &y_true);
+        assert!((score3 - 0.5).abs() < 1e-8);
+    }
+
+    #[cfg_attr(target_arch = "wasm32", wasm_bindgen_test::wasm_bindgen_test)]
+    #[test]
+    fn precision_multiclass() {
+        let y_true: Vec<f64> = vec![0., 0., 0., 1., 1., 1., 2., 2., 2.];
+        let y_pred: Vec<f64> = vec![0., 1., 2., 0., 1., 2., 0., 1., 2.];
+
+        let score1: f64 = Precision {}.get_score(&y_pred, &y_true);
+        let score2: f64 = Precision {}.get_score(&y_pred, &y_pred);
+
+        assert!((score1 - 0.333333333).abs() < 1e-8);
+        assert!((score2 - 1.0).abs() < 1e-8);
     }
 }

src/metrics/recall.rs

@@ -18,6 +18,9 @@
 //!
 //! <script src="https://polyfill.io/v3/polyfill.min.js?features=es6"></script>
 //! <script id="MathJax-script" async src="https://cdn.jsdelivr.net/npm/mathjax@3/es5/tex-mml-chtml.js"></script>
+use std::collections::HashSet;
+use std::convert::TryInto;
+
 #[cfg(feature = "serde")]
 use serde::{Deserialize, Serialize};
 
@@ -42,34 +45,32 @@ impl Recall {
             );
         }
 
+        let mut classes = HashSet::new();
+        for i in 0..y_true.len() {
+            classes.insert(y_true.get(i).to_f64_bits());
+        }
+        let classes: i64 = classes.len().try_into().unwrap();
+
         let mut tp = 0;
-        let mut p = 0;
+        let mut fne = 0;
-        let n = y_true.len();
+        for i in 0..y_true.len() {
-        for i in 0..n {
+            if y_pred.get(i) == y_true.get(i) {
-            if y_true.get(i) != T::zero() && y_true.get(i) != T::one() {
+                if classes == 2 {
-                panic!(
+                    if y_true.get(i) == T::one() {
-                    "Recall can only be applied to binary classification: {}",
+                        tp += 1;
-                    y_true.get(i)
+                    }
-                );
+                } else {
-            }
-
-            if y_pred.get(i) != T::zero() && y_pred.get(i) != T::one() {
-                panic!(
-                    "Recall can only be applied to binary classification: {}",
-                    y_pred.get(i)
-                );
-            }
-
-            if y_true.get(i) == T::one() {
-                p += 1;
-
-                if y_pred.get(i) == T::one() {
                     tp += 1;
                 }
+            } else if classes == 2 {
+                if y_true.get(i) != T::one() {
+                    fne += 1;
+                }
+            } else {
+                fne += 1;
             }
         }
-
+        T::from_i64(tp).unwrap() / (T::from_i64(tp).unwrap() + T::from_i64(fne).unwrap())
-        T::from_i64(tp).unwrap() / T::from_i64(p).unwrap()
     }
 }
 
@@ -88,5 +89,24 @@ mod tests {
 
         assert!((score1 - 0.5).abs() < 1e-8);
         assert!((score2 - 1.0).abs() < 1e-8);
+
+        let y_pred: Vec<f64> = vec![0., 0., 1., 1., 1., 1.];
+        let y_true: Vec<f64> = vec![0., 1., 1., 0., 1., 0.];
+
+        let score3: f64 = Recall {}.get_score(&y_pred, &y_true);
+        assert!((score3 - 0.66666666).abs() < 1e-8);
+    }
+
+    #[cfg_attr(target_arch = "wasm32", wasm_bindgen_test::wasm_bindgen_test)]
+    #[test]
+    fn recall_multiclass() {
+        let y_true: Vec<f64> = vec![0., 0., 0., 1., 1., 1., 2., 2., 2.];
+        let y_pred: Vec<f64> = vec![0., 1., 2., 0., 1., 2., 0., 1., 2.];
+
+        let score1: f64 = Recall {}.get_score(&y_pred, &y_true);
+        let score2: f64 = Recall {}.get_score(&y_pred, &y_pred);
+
+        assert!((score1 - 0.333333333).abs() < 1e-8);
+        assert!((score2 - 1.0).abs() < 1e-8);
     }
 }

src/preprocessing/numerical.rs

@@ -32,7 +32,11 @@ use crate::error::{Failed, FailedError};
 use crate::linalg::Matrix;
 use crate::math::num::RealNumber;
 
+#[cfg(feature = "serde")]
+use serde::{Deserialize, Serialize};
+
 /// Configure Behaviour of `StandardScaler`.
+#[cfg_attr(feature = "serde", derive(Serialize, Deserialize))]
 #[derive(Clone, Debug, Copy, Eq, PartialEq)]
 pub struct StandardScalerParameters {
     /// Optionaly adjust mean to be zero.
@@ -54,6 +58,7 @@ impl Default for StandardScalerParameters {
 /// deviation of one. This can improve model training for
 /// scaling sensitive models like neural network or nearest
 /// neighbors based models.
+#[cfg_attr(feature = "serde", derive(Serialize, Deserialize))]
 #[derive(Clone, Debug, Default, Eq, PartialEq)]
 pub struct StandardScaler<T: RealNumber> {
     means: Vec<T>,
@@ -400,5 +405,43 @@ mod tests {
                 Ok(DenseMatrix::from_2d_array(&[&[0.0, 3.0], &[2.0, 4.0]]))
             )
         }
+
+        /// Same as `fit_for_random_values` test, but using a `StandardScaler` that has been
+        /// serialized and deserialized.
+        #[cfg_attr(target_arch = "wasm32", wasm_bindgen_test::wasm_bindgen_test)]
+        #[test]
+        #[cfg(feature = "serde")]
+        fn serde_fit_for_random_values() {
+            let fitted_scaler = StandardScaler::fit(
+                &DenseMatrix::from_2d_array(&[
+                    &[0.1004222429, 0.2194113576, 0.9310663354, 0.3313593793],
+                    &[0.2045493861, 0.1683865411, 0.5071506765, 0.7257355264],
+                    &[0.5708488802, 0.1846414616, 0.9590802982, 0.5591871046],
+                    &[0.8387612750, 0.5754861361, 0.5537109852, 0.1077646442],
+                ]),
+                StandardScalerParameters::default(),
+            )
+            .unwrap();
+
+            let deserialized_scaler: StandardScaler<f64> =
+                serde_json::from_str(&serde_json::to_string(&fitted_scaler).unwrap()).unwrap();
+
+            assert_eq!(
+                deserialized_scaler.means,
+                vec![0.42864544605, 0.2869813741, 0.737752073825, 0.431011663625],
+            );
+
+            assert!(
+                &DenseMatrix::from_2d_vec(&vec![deserialized_scaler.stds]).approximate_eq(
+                    &DenseMatrix::from_2d_array(&[&[
+                        0.29426447500954,
+                        0.16758497615485,
+                        0.20820945786863,
+                        0.23329718831165
+                    ],]),
+                    0.00000000000001
+                )
+            )
+        }
     }
 }