dev-vivekkumarverma / memoization

memoisation is an optimization technique used primarily to speed up computer programs by storing the results of expensive function calls to pure functions and returning the cached result when the same inputs occur again.

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Memoization in Python: Optimizing Fibonacci Calculation

Introduction

This repository demonstrates the use of memoization, a powerful technique to optimize recursive functions, using the example of calculating Fibonacci numbers in Python.

Overview

The provided Jupyter Notebook (recursion.ipynb) contains two implementations of the Fibonacci sequence calculation:

1. A naive recursive approach.
2. An optimized approach using memoization.

File Contents

• recursion.ipynb: Contains the Python code for both the naive and memoized implementations of the Fibonacci sequence calculation.

Installation

1. Clone the repository to your local machine.
2. Ensure you have Jupyter Notebook installed.
3. Open recursion.ipynb using Jupyter Notebook.

Usage

Naive Recursive Approach

import time

@timeProfiler
def find_feb(n):
    def feb(n):
        if n == 1:
            return 0
        elif n == 2:
            return 1
        else:
            return feb(n - 1) + feb(n - 2)
        
    return feb(n)

result, execution_time = find_feb(19)
print(f"Result: {result}, Execution Time: {execution_time} seconds")

Memoized Approach

import time

@timeProfiler
def find_feb_with_memo(n):
    memo = {}
    
    def feb_memoised(n):
        if n in memo:
            return memo[n]
        if n == 1:
            return 0
        elif n == 2:
            return 1
        else:
            res = feb_memoised(n - 1) + feb_memoised(n - 2)
            memo[n] = res
            return res
    
    return feb_memoised(n)

result, execution_time = find_feb_with_memo(19)
print(f"Result: {result}, Execution Time: {execution_time} seconds")

Conclusion

Memoization significantly reduces computation time by storing previously computed results. This is evident from the comparison of execution times between the naive and memoized approaches.

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