page rank Algorithm
PageRank (PR) is an algorithm used by Google search to rank web pages in their search engine outcomes. presently, PageRank is not the only algorithm used by Google to order search outcomes, but it is the first algorithm that was used by the company, and it is the best known. Shortly after, page and Brin established Google Inc., the company behind the Google search engine. Rajeev Motwani and Terry Winograd co-authored with page and Brin the first paper about the project, describe PageRank and the initial prototype of the Google search engine, published in 1998.Larry page and Sergey Brin developed PageRank at Stanford University in 1996 as part of a research project about a new kind of search engine.
"""
Author: https://github.com/bhushan-borole
"""
"""
The input graph for the algorithm is:
A B C
A 0 1 1
B 0 0 1
C 1 0 0
"""
graph = [[0, 1, 1], [0, 0, 1], [1, 0, 0]]
class Node:
def __init__(self, name):
self.name = name
self.inbound = []
self.outbound = []
def add_inbound(self, node):
self.inbound.append(node)
def add_outbound(self, node):
self.outbound.append(node)
def __repr__(self):
return f"Node {self.name}: Inbound: {self.inbound} ; Outbound: {self.outbound}"
def page_rank(nodes, limit=3, d=0.85):
ranks = {}
for node in nodes:
ranks[node.name] = 1
outbounds = {}
for node in nodes:
outbounds[node.name] = len(node.outbound)
for i in range(limit):
print(f"======= Iteration {i + 1} =======")
for j, node in enumerate(nodes):
ranks[node.name] = (1 - d) + d * sum(
[ranks[ib] / outbounds[ib] for ib in node.inbound]
)
print(ranks)
def main():
names = list(input("Enter Names of the Nodes: ").split())
nodes = [Node(name) for name in names]
for ri, row in enumerate(graph):
for ci, col in enumerate(row):
if col == 1:
nodes[ci].add_inbound(names[ri])
nodes[ri].add_outbound(names[ci])
print("======= Nodes =======")
for node in nodes:
print(node)
page_rank(nodes)
if __name__ == "__main__":
main()
