2024 Challenge: MPI parallelization

[Onotate]

This PR contains the change proposed in issue #5 .

Changes to src/mpi/main.c:

• Added graph node distribution to MPI processes and modified the page rank update function to work only on the delegated nodes.
• MPI processes can gather all page ranks from each other.
• Added MPI code to reduce page rank total and page rank difference.
• Designated the last MPI process to be the time keeper and broadcast its time to synchronize all MPI processes.

Changes to submission script:

• Configuration: 16 procs on 1 node.

Number of iterations achieved: 15k.

Code explanation and performance measurement will be posted in subsequent comments.

[Onotate]

Performance

Using generate_nice_graph:

0.00 seconds to generate the nice graph.                                                                                    
0.00 seconds to generate the nice graph.                                                                                    
0.00 seconds to generate the nice graph.                                                                                    
0.00 seconds to generate the nice graph.                                                                                    
0.00 seconds to generate the nice graph.                                                                                    
0.00 seconds to generate the nice graph.                                                                                    
0.00 seconds to generate the nice graph.                                                                                    
0.00 seconds to generate the nice graph.                                                                                    
0.00 seconds to generate the nice graph.                                                                                    
0.00 seconds to generate the nice graph.                                                                                    
0.00 seconds to generate the nice graph.                                                                                    
0.00 seconds to generate the nice graph.                                                                                    
0.00 seconds to generate the nice graph.                                                                                    
0.00 seconds to generate the nice graph.                                                                                    
0.00 seconds to generate the nice graph.                                                                                    
0.00 seconds to generate the nice graph.                                                                                    
15564 iterations achieved in 10.00 seconds                                                                                  
PageRank of vertex 0: 0.001000                                                                                              
PageRank of vertex 100: 0.001000                                                                                            
PageRank of vertex 200: 0.001000                                                                                            
PageRank of vertex 300: 0.001000                                                                                            
PageRank of vertex 400: 0.001000                                                                                            
PageRank of vertex 500: 0.001000                                                                                            
PageRank of vertex 600: 0.001000                                                                                            
PageRank of vertex 700: 0.001000                                                                                            
PageRank of vertex 800: 0.001000                                                                                            
PageRank of vertex 900: 0.001000                                                                                            
Sum of all pageranks = 1.000000000000, total diff = 0.000000000000, max diff = 0.000000000000 and min diff = 0.000000000000.

Using generate_sneaky_graph:

0.00 seconds to generate the sneaky graph.
0.00 seconds to generate the sneaky graph.
0.00 seconds to generate the sneaky graph.
0.00 seconds to generate the sneaky graph.
0.00 seconds to generate the sneaky graph.
0.00 seconds to generate the sneaky graph.
0.00 seconds to generate the sneaky graph.
0.00 seconds to generate the sneaky graph.
0.00 seconds to generate the sneaky graph.
0.00 seconds to generate the sneaky graph.
0.00 seconds to generate the sneaky graph.
0.00 seconds to generate the sneaky graph.
0.00 seconds to generate the sneaky graph.
0.00 seconds to generate the sneaky graph.
0.00 seconds to generate the sneaky graph.
0.00 seconds to generate the sneaky graph.
16097 iterations achieved in 10.00 seconds
PageRank of vertex 0: 0.002541
PageRank of vertex 100: 0.001726
PageRank of vertex 200: 0.001494
PageRank of vertex 300: 0.001302
PageRank of vertex 400: 0.001127
PageRank of vertex 500: 0.000962
PageRank of vertex 600: 0.000800
PageRank of vertex 700: 0.000641
PageRank of vertex 800: 0.000483
PageRank of vertex 900: 0.000322
Sum of all pageranks = 1.000000000000, total diff = 1.168591825342, max diff = 0.624703182089 and min diff = 0.000000000000.
Total time taken: 10.0051 seconds.