CODEWITHSUNDEEP
pythonperformance
nicola
nicola

Reputation: 29

Speed issues with python

I'm struggling with speeding up my python code. I think that the main bottleneck of my code is located in the following function, where k is a counter, m is an empty matrix and image3 is a matrix that contains 0s and 1s. Do you have any suggestion? p.s I have already try to use Cython without much success, so I was wondering if there are some simpler way of solving the problem. Thank you in advance for help.

    def make_step(k,m,image3):
     
      for i in range(len(m)):
         
        for j in range(len(m[i])):
          if m[i][j] == k:
             
            if i>0 and m[i-1][j] == 0 and image3[i-1][j] == 0:   
              m[i-1][j] = k + 1  
              
               
            if j>0 and m[i][j-1] == 0 and image3[i][j-1] == 0:
              m[i][j-1] = k + 1  
              
             
            if i<len(m)-1 and m[i+1][j] == 0 and image3[i+1][j] == 0:
              m[i+1][j] = k + 1   
              
             
            if j<len(m[i])-1 and m[i][j+1] == 0 and image3[i][j+1] == 0:
              m[i][j+1] = k + 1

Upvotes: 2

Views: 80

Answers (1)

Glauco
Glauco

Reputation: 1465

I agree with Booboo, your code need review, and i suggest following approach:

Do a good benchmark to see where the time is spent. For these kind of problem perf_tool is a valid tool designed for this[*]. After you know where the code lack, you can rewrite the internal loop in vectorial using mask approach. This let you to reduce problem from O(n*m) to O(n)

[*] I'm the main developer of perf_tool

Upvotes: 1

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