From 1ad1ed35623c2be80ed4bc3b7a08b8c7c8aadb2d Mon Sep 17 00:00:00 2001
From: Soham-KT <sohamkothariprof79@gmail.com>
Date: Sat, 5 Oct 2024 18:38:12 +0530
Subject: [PATCH] weddle's integration rule

---
 maths/weddles_rule.py | 109 ++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 109 insertions(+)
 create mode 100644 maths/weddles_rule.py

diff --git a/maths/weddles_rule.py b/maths/weddles_rule.py
new file mode 100644
index 000000000..ea9b547e8
--- /dev/null
+++ b/maths/weddles_rule.py
@@ -0,0 +1,109 @@
+from math import *
+
+
+def get_inputs():
+    """
+    Get user input for the function, lower limit, and upper limit.
+
+    Returns:
+        tuple: A tuple containing the function as a string, the lower limit (a), and the upper limit (b) as floats.
+
+    Example:
+        >>> from unittest.mock import patch
+        >>> inputs = ['1/(1+x**2)', 1.0, -1.0]
+        >>> with patch('builtins.input', side_effect=inputs):
+        ...     get_inputs()
+        ('1/(1+x**2)', 1.0, -1.0)
+    """
+    func = input("Enter function with variable as x: ")
+    a = float(input("Enter lower limit: "))
+    b = float(input("Enter upper limit: "))
+    return func, a, b
+
+
+def compute_table(func, a, b, acc):
+    """
+    Compute the table of function values based on the limits and accuracy.
+
+    Args:
+        func (str): The mathematical function with the variable 'x' as a string.
+        a (float): The lower limit of the integral.
+        b (float): The upper limit of the integral.
+        acc (int): The number of subdivisions for accuracy.
+
+    Returns:
+        tuple: A tuple containing the table of values and the step size (h).
+
+    Example:
+        >>> compute_table('1/(1+x**2)', 1, -1, 1)
+        ([0.5, 0.4235294117647058, 0.36, 0.3076923076923077, 0.26470588235294124, 0.22929936305732482, 0.2], -0.3333333333333333)
+    """
+    h = (b - a) / (acc * 6)
+    table = [0 for _ in range(acc * 6 + 1)]
+    for j in range(acc * 6 + 1):
+        x = a + j / (acc * 6)
+        table[j] = eval(func)
+    return table, h
+
+
+def apply_weights(table):
+    """
+    Apply Simpson's rule weights to the values in the table.
+
+    Args:
+        table (list): A list of computed function values.
+
+    Returns:
+        list: A list of weighted values.
+
+    Example:
+        >>> apply_weights([0.0, 0.866, 1.0, 0.866, 0.0, -0.866, -1.0])
+        [4.33, 1.0, 5.196, 0.0, -4.33]
+    """
+    add = []
+    for i in range(1, len(table) - 1):
+        if i % 2 == 0 and i % 3 != 0:
+            add.append(table[i])
+        if i % 2 != 0 and i % 3 != 0:
+            add.append(5 * table[i])
+        elif i % 6 == 0:
+            add.append(2 * table[i])
+        elif i % 3 == 0 and i % 2 != 0:
+            add.append(6 * table[i])
+    return add
+
+
+def compute_solution(add, table, h):
+    """
+    Compute the final solution using the weighted values and table.
+
+    Args:
+        add (list): A list of weighted values from apply_weights.
+        table (list): A list of function values.
+        h (float): The step size (h) calculated from the limits and accuracy.
+
+    Returns:
+        float: The final computed integral solution.
+
+    Example:
+        >>> compute_solution([4.33, 6.0, 0.0, -4.33], [0.0, 0.866, 1.0, 0.866, 0.0, -0.866, -1.0], 0.5235983333333333)
+        0.7853975
+    """
+    return 0.3 * h * (sum(add) + table[0] + table[-1])
+
+
+if __name__ == "__main__":
+    from doctest import testmod
+    testmod()
+    
+    func, a, b = get_inputs()
+    acc = 1
+    solution = None
+
+    while acc <= 100000:
+        table, h = compute_table(func, a, b, acc)
+        add = apply_weights(table)
+        solution = compute_solution(add, table, h)
+        acc *= 10
+
+    print(f'Solution: {solution}')
\ No newline at end of file