How to vectorize 'for' loop in this code?

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Mr. 206 2018-11-22

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编辑： madhan ravi 2018-11-22

My code is like this...

c = 0;     
      for j = 3: 2 : size(READ,2)           
          c = c+1; 
      output(c) = .....
   end 

I want avoid 'c' and 'for loop' in my code but as you are seeing it is necessary to store the results of loop.

I want it to be like this

    j = 3: 2 : size(READ,2)           
      output = ....

But in this case all the outputs are not stored. I want this thing to make my code faster.

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Jan 2018-11-22

编辑：Jan 2018-11-22

There is no benefit in vectorizing in general. Depending on what is hidden in ".....", a vectorized version can be slower or impossible to create. So please post this very important detail.

Using the index c is nice and efficient, if you pre-allocate the array output.

Mr. 206 2018-11-22

Thanks.

I thought vectoring will make my code faster.

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Answer 1

madhan ravi 2018-11-22

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https://ww2.mathworks.cn/matlabcentral/answers/431344-how-to-vectorize-for-loop-in-this-code#answer_348342

You can preallocate output before the loop but to store the output your first way is the only way.

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Mr. 206 2018-11-22

编辑：madhan ravi 2018-11-22

Thanks.

I will do so .

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How to vectorize 'for' loop in this code?

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