MPI Online Quiz, 3rd quarter

Download the shell practice quiz program, quizshell.c

Also see the answer form (.doc version)

Remember to try and run programs using the /tmp directory - Here's how

Write a parallel application for factorial(n)

1. Enter a number in process 0, for example 8
2. Each process finds the partial product of the factorial(n) - Example (for four processes), process 0 finds 1*2; process 1 finds 3*4; process 2 finds 5*6; and process 3 finds 7*8.
3. Use MPI_Reduce and MPI_PROD to find the product of all of these partial products - Example, process 0 finds 2 * 12 * 30 * 56 = 40320
4. Process 0 prints the result (40320).
5. This example shell program uses a while loop that repeats until the user enters a 0
6. More examples:

     Number = 4, numprocesses = 4 
       Rank 0: 1
       Rank 1: 2
       Rank 2: 3
       Rank 3: 4
   
       Rank 0, using MPI_Reduce and MPI_PROD, calculates: 1*2*3*4=24
   
     Number = 12, numprocesses = 4
       Rank 0: 1*2*3
       Rank 1: 4*5*6
       Rank 2: 7*8*9
       Rank 3: 10*11*12
   
       Rank 0, using MPI_Reduce and MPI_PROD, calculates: 6*120*504*1320=479001600
   

   In these examples, the number of processes divides evenly into n

7. Extra - write a version in which numproc does not necessarily divide evenly into n

   Example of the extra version:

     Number = 10, numprocesses = 4
       Rank 0: 1*2*3
       Rank 1: 4*5*6
       Rank 2: 7*8*9
       Rank 3: 10
   
       Rank 0, using MPI_Reduce and MPI_PROD, calculates: 6*120*504*10=3628800
   
     Number = 11, numprocesses = 4
       Rank 0: 1*2*3
       Rank 1: 4*5*6
       Rank 2: 7*8*9
       Rank 3: 10*11
   
       Rank 0, using MPI_Reduce and MPI_PROD, calculates: 6*120*504*110=39916800
   
     Number = 9, numprocesses = 4
       Rank 0: 1*2
       Rank 1: 3*4
       Rank 2: 5*6
       Rank 3: 7*8*9
   
       Rank 0, using MPI_Reduce and MPI_PROD, calculates: 2*12*30*504=362880