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  1. from mrjob.job import MRJob
  2. from mrjob.step import MRStep
  3.  
  4. class MatrixMultiplication(MRJob):
  5.  
  6.     def mapper(self, _, line):
  7.         # Read input line
  8.         matrix, i, j, value = line.split()
  9.         i, j, value = int(i), int(j), int(value)
  10.  
  11.         # If it's from matrix A, send to appropriate column in result
  12.         if matrix == "A":
  13.             for k in range(2):  # Assume B has 2 columns
  14.                 yield (i, k), ("A", j, value)
  15.  
  16.         # If it's from matrix B, send to appropriate row in result
  17.         elif matrix == "B":
  18.             for k in range(2):  # Assume A has 2 rows
  19.                 yield (k, j), ("B", i, value)
  20.  
  21.     def reducer(self, key, values):
  22.         A_values = {}
  23.         B_values = {}
  24.  
  25.         # Collect values
  26.         for matrix, index, value in values:
  27.             if matrix == "A":
  28.                 A_values[index] = value
  29.             else:
  30.                 B_values[index] = value
  31.  
  32.         # Multiply and sum up
  33.         result = sum(A_values.get(k, 0) * B_values.get(k, 0) for k in range(2))
  34.         yield key, result
  35.  
  36. if __name__ == '__main__':
  37.     MatrixMultiplication.run()
Success #stdin #stdout #stderr 0.01s 5292KB
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Error: near line 1: near "from": syntax error
https://ideone.com/JFCMNM
language:
SQLite (sqlite 3.27.2)
created:
11 days ago
visibility:
public

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