feat: adds dataset module, fixs problem in CoverTree implementation

src/dataset/mod.rs

@@ -0,0 +1,65 @@
+//! Datasets
+//!
+//! In this module you will find small datasets that are used in SmartCore for demonstration purpose mostly.
+
+/// Iris flower data set
+pub mod iris;
+
+/// Dataset
+pub struct Dataset<X, Y> {
+    /// data in one-dimensional array.
+    pub data: Vec<X>,
+    /// target values or class labels.
+    pub target: Vec<Y>,
+    /// number of samples (number of rows in matrix form).
+    pub num_samples: usize,
+    /// number of features (number of columns in matrix form).
+    pub num_features: usize,
+    /// names of dependent variables.
+    pub feature_names: Vec<String>,
+    /// names of target variables.
+    pub target_names: Vec<String>,
+    /// dataset description
+    pub description: String,
+}
+
+impl<X, Y> Dataset<X, Y> {
+    /// Reshape data into a two-dimensional matrix
+    pub fn as_2d_vector(&self) -> Vec<Vec<&X>> {
+        let mut result: Vec<Vec<&X>> = Vec::with_capacity(self.num_samples);
+
+        for r in 0..self.num_samples {
+            let mut row = Vec::with_capacity(self.num_features);
+            for c in 0..self.num_features {
+                row.push(&self.data[r * self.num_features + c]);
+            }
+            result.push(row);
+        }
+
+        result
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    #[test]
+    fn as_2d_vector() {
+        let dataset = Dataset {
+            data: vec![1, 2, 3, 4, 5, 6, 7, 8, 9, 10],
+            target: vec![1, 2, 3],
+            num_samples: 2,
+            num_features: 5,
+            feature_names: vec![],
+            target_names: vec![],
+            description: "".to_string(),
+        };
+
+        let m = dataset.as_2d_vector();
+
+        assert_eq!(m.len(), 2);
+        assert_eq!(m[0].len(), 5);
+        assert_eq!(*m[1][3], 9);
+    }
+}