Organize code structure by adding section comments

src/matrix/mat.rs

@@ -314,6 +314,8 @@ impl<T> IndexMut<(usize, usize)> for Matrix<T> {
     }
 }
 
+// --- Row Iterator Helper ---
+
 /// Represents an immutable view of a single row in the matrix.
 pub struct MatrixRow<'a, T> {
     matrix: &'a Matrix<T>,
@@ -328,10 +330,12 @@ impl<'a, T> MatrixRow<'a, T> {
 
     /// Returns an iterator over all elements in this row.
     pub fn iter(&self) -> impl Iterator<Item = &T> {
-        (0..self.matrix.cols).map(move |c| &self.matrix[(self.row, c)])
+        (0..self.matrix.cols).map(move |c| self.get(c))
     }
 }
 
+// --- Reduction Axis Enum ---
+
 /// Specifies the axis along which to perform a reduction operation.
 #[derive(Clone, Copy, Debug, PartialEq, Eq)]
 pub enum Axis {
@@ -363,6 +367,8 @@ impl<T: Clone> Broadcastable<T> for Matrix<T> {
     }
 }
 
+// --- Element-wise Comparisons ---
+
 /// Generates element-wise eq, lt, le, gt and ge methods
 /// where the rhs can be a `Matrix<T>` or a scalar T.
 macro_rules! impl_elementwise_cmp {
@@ -612,11 +618,15 @@ impl Not for &Matrix<bool> {
     }
 }
 
+// --- Type Aliases ---
 pub type FloatMatrix = Matrix<f64>;
 pub type BoolMatrix = Matrix<bool>;
 pub type IntMatrix = Matrix<i32>;
 pub type StringMatrix = Matrix<String>;
 
+
+// --- Unit Tests ---
+
 #[cfg(test)]
 mod tests {
     use crate::matrix::BoolOps;