feat: simplifies LR API

src/linalg/mod.rs

@@ -6,6 +6,12 @@ pub mod ndarray_bindings;
 
 pub trait Matrix: Clone + Debug {  
 
+    type RowVector: Clone + Debug;
+
+    fn from_row_vector(vec: Self::RowVector) -> Self;
+
+    fn to_row_vector(self) -> Self::RowVector;
+
     fn from_array(nrows: usize, ncols: usize, values: &[f64]) -> Self;
     
     fn from_vec(nrows: usize, ncols: usize, values: Vec<f64>) -> Self;

src/linalg/naive/dense_matrix.rs

@@ -107,7 +107,17 @@ impl Into<Vec<f64>> for DenseMatrix {
     }
 }
 
-impl Matrix for DenseMatrix {    
+impl Matrix for DenseMatrix {   
+    
+    type RowVector = Vec<f64>;
+
+    fn from_row_vector(vec: Self::RowVector) -> Self{
+        DenseMatrix::from_vec(1, vec.len(), vec)
+    }
+
+    fn to_row_vector(self) -> Self::RowVector{
+        self.to_raw_vector()
+    }
 
     fn from_array(nrows: usize, ncols: usize, values: &[f64]) -> DenseMatrix {
         DenseMatrix::from_vec(nrows, ncols, Vec::from(values)) 
@@ -968,6 +978,15 @@ impl Matrix for DenseMatrix {
 mod tests {    
     use super::*; 
 
+    #[test]
+    fn from_to_row_vec() { 
+
+        let vec = vec![ 1.,  2.,  3.];
+        assert_eq!(DenseMatrix::from_row_vector(vec.clone()), DenseMatrix::from_vec(1, 3, vec![1., 2., 3.]));
+        assert_eq!(DenseMatrix::from_row_vector(vec.clone()).to_row_vector(), vec![1., 2., 3.]);
+
+    }
+
     #[test]
     fn qr_solve_mut() { 
 

src/linalg/ndarray_bindings.rs

@@ -1,9 +1,20 @@
 use std::ops::Range;
 use crate::linalg::{Matrix};
-use ndarray::{Array, ArrayBase, OwnedRepr, Ix2, Axis, stack, s};
+use ndarray::{Array, ArrayBase, OwnedRepr, Ix2, Ix1, Axis, stack, s};
 
 impl Matrix for ArrayBase<OwnedRepr<f64>, Ix2>
 {
+    type RowVector = ArrayBase<OwnedRepr<f64>, Ix1>;
+
+    fn from_row_vector(vec: Self::RowVector) -> Self{
+        let vec_size = vec.len();
+        vec.into_shape((1, vec_size)).unwrap()
+    }
+
+    fn to_row_vector(self) -> Self::RowVector{
+        let vec_size = self.nrows() * self.ncols();
+        self.into_shape(vec_size).unwrap()
+    }
 
     fn from_array(nrows: usize, ncols: usize, values: &[f64]) -> Self {
         Array::from_shape_vec((nrows, ncols), values.to_vec()).unwrap()     
@@ -248,7 +259,16 @@ impl Matrix for ArrayBase<OwnedRepr<f64>, Ix2>
 #[cfg(test)]
 mod tests {    
     use super::*; 
-    use ndarray::{arr2, Array2};
+    use ndarray::{arr1, arr2, Array2};
+
+    #[test]
+    fn from_to_row_vec() { 
+
+        let vec = arr1(&[ 1.,  2.,  3.]);
+        assert_eq!(Array2::from_row_vector(vec.clone()), arr2(&[[1., 2., 3.]]));
+        assert_eq!(Array2::from_row_vector(vec.clone()).to_row_vector(), arr1(&[1., 2., 3.]));
+
+    }
 
     #[test]
     fn add_mut() {