From 8f35a08d215246823bbce610e3b68da7443272b9 Mon Sep 17 00:00:00 2001
From: Palash Tyagi <23239946+Magnus167@users.noreply.github.com>
Date: Sat, 26 Apr 2025 17:43:22 +0100
Subject: [PATCH] Refactor README example to improve type annotations and
 clarity in matrix operations

---
 README.md | 49 +++++++++++++++++++++++++------------------------
 1 file changed, 25 insertions(+), 24 deletions(-)

diff --git a/README.md b/README.md
index 93624e0..d44e91c 100644
--- a/README.md
+++ b/README.md
@@ -53,34 +53,35 @@ let dates: Vec<NaiveDate> =
         .list()
         .unwrap();
 
-let col_names = vec!["a".to_string(), "b".to_string()];
+    let col_names: Vec<String> = vec!["a".to_string(), "b".to_string()];
 
-let ma = Matrix::from_cols(vec![vec![1.0, 2.0, 3.0, 4.0], vec![5.0, 6.0, 7.0, 8.0]]);
-let mb = Matrix::from_cols(vec![vec![4.0, 3.0, 2.0, 1.0], vec![8.0, 7.0, 6.0, 5.0]]);
+    let ma: Matrix<f64> = Matrix::from_cols(vec![vec![1.0, 2.0, 3.0, 4.0], vec![5.0, 6.0, 7.0, 8.0]]);
+    let mb: Matrix<f64> = Matrix::from_cols(vec![vec![4.0, 3.0, 2.0, 1.0], vec![8.0, 7.0, 6.0, 5.0]]);
 
-let fa = Frame::new(
-    ma.clone(),
-    col_names.clone(),
-    Some(RowIndex::Date(dates.clone())),
-);
-let fb = Frame::new(mb, col_names, Some(RowIndex::Date(dates)));
+    let fa: Frame<f64> = Frame::new(
+        ma.clone(),
+        col_names.clone(),
+        Some(RowIndex::Date(dates.clone())),
+    );
+    let fb: Frame<f64> = Frame::new(mb, col_names, Some(RowIndex::Date(dates)));
 
-// Math that reads like math
-let result = &fa * &fb; // element‑wise multiply
-let total = result.sum_vertical().iter().sum::<f64>();
-assert_eq!(total, 184.0);
+    // Math that reads like math
+    let result: Frame<f64> = &fa * &fb; // element‑wise multiply
+    let total: f64 = result.sum_vertical().iter().sum::<f64>();
+    assert_eq!(total, 184.0);
 
-let result = &ma + 1.0; // add scalar
-let result = &result - 1.0; // subtract scalar
-let result = &result * 2.0; // multiply by scalar
-let result = &result / 2.0; // divide by scalar
+    // broadcast & reduce
+    let result: Matrix<f64> = &ma + 1.0; // add scalar
+    let result: Matrix<f64> = &result - 1.0; // subtract scalar
+    let result: Matrix<f64> = &result * 2.0; // multiply by scalar
+    let result: Matrix<f64> = &result / 2.0; // divide by scalar
 
-let check = result.eq_elementwise(ma.clone()).all();
-assert!(check);
+    let check: bool = result.eq_elementwise(ma.clone()).all();
+    assert!(check);
 
-// The above math can also be written as:
-let check = &(&(&(&(&ma + 1.0) - 1.0) * 2.0) / 2.0)
-    .eq_elementwise(ma)
-    .all();
-assert!(check);
+    // The above math can also be written as:
+    let check: bool = (&(&(&(&ma + 1.0) - 1.0) * 2.0) / 2.0)
+        .eq_elementwise(ma)
+        .all();
+    assert!(check);
 ```