From 2bd853e8fde52bd8a0287397354b43a78bb9012e Mon Sep 17 00:00:00 2001
From: Ameya Chawla <88154798+ameyachawlaggsipu@users.noreply.github.com>
Date: Thu, 4 Nov 2021 14:55:32 +0530
Subject: [PATCH] feat : Implemented Babylonian Method

Babylonian method is used to calculate  square roots .
---
 numerical_methods/babylonian_method.cpp | 98 +++++++++++++++++++++++++
 1 file changed, 98 insertions(+)
 create mode 100644 numerical_methods/babylonian_method.cpp

diff --git a/numerical_methods/babylonian_method.cpp b/numerical_methods/babylonian_method.cpp
new file mode 100644
index 000000000..d3ac4d05c
--- /dev/null
+++ b/numerical_methods/babylonian_method.cpp
@@ -0,0 +1,98 @@
+/**
+ * @file
+ * @brief [A babylonian method
+ * (BM)](https://en.wikipedia.org/wiki/Methods_of_computing_square_roots#Babylonian_method)
+ * is an algorithm that computes the square root.
+ * @details
+ * This algorithm has an application in use case scenario where a user wants find accurate square roots of large numbers
+ * @author [Ameya Chawla](https://github.com/ameyachawlaggsipu)
+ */
+
+#include <iostream> /// for IO operations
+#include <cassert>   /// for assert
+
+/**
+ * @namespace numerical_methods
+ * @brief Numerical algorithms/methods
+ */
+
+namespace numerical_methods{
+   
+/**
+ * @brief Babylonian methods is an iterative function which returns 
+ * square root of radicand
+ * @param radicand is the radicand
+ * @returns x1 the square root of radicand
+ */
+
+double babylonian_method(double radicand){
+    
+    int i=1; /// To find initial root or rough approximation
+    
+    while(i*i<=radicand){
+        i++;
+    } 
+    
+    i--; /// Real Initial value will be i-1 as loop stops on +1 value
+    
+    double x0=i; ///Storing previous value for comparison
+    double x1=(radicand/x0+x0)/2; /// Storing calculated value for comparison
+    double temp; /// Temp variable to x0 and x1
+    
+    while(std::max(x0,x1)-std::min(x0,x1)<0.0001)
+    {
+        temp=(radicand/x1+x1)/2; /// Newly calculated root
+        x0=x1;
+        x1=temp;
+    }
+     
+    
+    return x1; ///Returning final root
+}
+
+
+} // namespace numerical_methods 
+
+/**
+ * @brief Self-test implementations
+ * @details
+ * Declaring two test cases and checking for the error
+ * in predicted and true value is less than 0.0001.
+ * @returns void
+ */
+static void test() {
+    /* descriptions of the following test */
+    
+    auto testcase1 = 125348; /// Testcase 1
+    auto testcase2 = 752080; /// Testcase 2
+    
+    auto real_output1 = 354.045194855; /// Real Output 1
+    auto real_output2 = 867.225460881; /// Real Output 2
+    
+    auto test_result1 = numerical_methods::babylonian_method(testcase1);
+    /// Test result for testcase 1
+    auto test_result2 = numerical_methods::babylonian_method(testcase2);
+    /// Test result for testcase 2
+    
+    assert(std::max(test_result1,real_output1)-std::min(test_result1,real_output1)<0.0001);
+    /// Testing for test Case 1
+    assert(std::max(test_result2,real_output2)-std::min(test_result2,real_output2)<0.0001);
+    /// Testing for test Case 2 
+    
+    std::cout << "All tests have successfully passed!\n";
+}
+
+
+/**
+ * @brief Main function
+ * @param argc commandline argument count (ignored)
+ * @param argv commandline array of arguments (ignored)
+ * calls automated test function to test the working of fast fourier transform.
+ * @returns 0 on exit
+ */
+
+int main(int argc, char const *argv[]) {
+    test();  //  run self-test implementations
+             //  with 2 defined test cases
+    return 0;
+}