From 47dd3cdbe2e7e3c2863a9257b06912436585c8df Mon Sep 17 00:00:00 2001
From: Paul Thuret <thuret.paul@gmail.com>
Date: Fri, 20 Dec 2024 13:47:00 +0100
Subject: [PATCH] UP my solution

---
 numpy_questions.py | 15 +++++++++------
 1 file changed, 9 insertions(+), 6 deletions(-)

diff --git a/numpy_questions.py b/numpy_questions.py
index 07a10c1..a9485c4 100644
--- a/numpy_questions.py
+++ b/numpy_questions.py
@@ -37,10 +37,11 @@ def max_index(X):
         If the input is not a numpy array or
         if the shape is not 2D.
     """
-    i = 0
-    j = 0
+    if not isinstance(X, np.ndarray) or X.ndim != 2:
+        raise ValueError("Input must be a 2D numpy array.")
 
-    # TODO
+    max_index_flat = np.argmax(X)
+    i, j = np.unravel_index(max_index_flat, X.shape)
 
     return i, j
 
@@ -62,6 +63,8 @@ def wallis_product(n_terms):
     pi : float
         The approximation of order `n_terms` of pi using the Wallis product.
     """
-    # XXX : The n_terms is an int that corresponds to the number of
-    # terms in the product. For example 10000.
-    return 0.
+    product = 1.0
+    for i in range(1, n_terms + 1):
+        term = (4 * i**2) / (4 * i**2 - 1)
+        product *= term
+    return 2 * product