Reduce memory consumption of numpy function












1












$begingroup$


I have a Numpy function that takes the values of an existing array X and a size (int) k equivalent to the columns of the array. This function does some calculations in a new array, to finally output the new array after the calculations are done.



def ff(x, k):
newarr = np.zeros((x.shape[0], 1), dtype=np.uint32)
newarr[:, 0] = x[:, 0] * 4
for i in range(1, k - 1):
newarr[:, 0] += x[:, i]
newarr[:, 0] = newarr[:, 0] * 4
newarr[:, 0] += x[:, -1]
return newarr


newarr it's the array where the calculated data is stored, it's initialized with np.zeros and a dtype, and it has a shape of (y,1) where y is the length of the x array.



The first step is to store in the (only) column of the newarr the multiplication of the first column of the x by 4.



The iteration occurs over the columns 1 to k-1 of the original array (x).
Inside the iteration, the next step is to sum the values of the first column of x to the column of newarr.
Next, to multiply the column of newarr by 4
To finally, after the iteration is complete, sum the last column of the original array x to the column of newarr.



I'm looking for a way (if there's any) to avoid the creation of the newarr, and do the calculations in the original array. This', to reduce the memory usage of this function, mainly because the x tends to be very big in execution.



The x array looks like this.



array([[3, 3, 0, 1],
[3, 0, 1, 0],
[0, 1, 0, 2],
[1, 0, 2, 2],
[0, 2, 2, 3],
[2, 2, 3, 1],
[2, 3, 1, 3],
.
.
.
[2, 2, 0, 1]], dtype=uint8)


In this case, the k value would be 4



Any additional improvement in the code is well received!
Thanks for your time.










share|improve this question









$endgroup$

















    1












    $begingroup$


    I have a Numpy function that takes the values of an existing array X and a size (int) k equivalent to the columns of the array. This function does some calculations in a new array, to finally output the new array after the calculations are done.



    def ff(x, k):
    newarr = np.zeros((x.shape[0], 1), dtype=np.uint32)
    newarr[:, 0] = x[:, 0] * 4
    for i in range(1, k - 1):
    newarr[:, 0] += x[:, i]
    newarr[:, 0] = newarr[:, 0] * 4
    newarr[:, 0] += x[:, -1]
    return newarr


    newarr it's the array where the calculated data is stored, it's initialized with np.zeros and a dtype, and it has a shape of (y,1) where y is the length of the x array.



    The first step is to store in the (only) column of the newarr the multiplication of the first column of the x by 4.



    The iteration occurs over the columns 1 to k-1 of the original array (x).
    Inside the iteration, the next step is to sum the values of the first column of x to the column of newarr.
    Next, to multiply the column of newarr by 4
    To finally, after the iteration is complete, sum the last column of the original array x to the column of newarr.



    I'm looking for a way (if there's any) to avoid the creation of the newarr, and do the calculations in the original array. This', to reduce the memory usage of this function, mainly because the x tends to be very big in execution.



    The x array looks like this.



    array([[3, 3, 0, 1],
    [3, 0, 1, 0],
    [0, 1, 0, 2],
    [1, 0, 2, 2],
    [0, 2, 2, 3],
    [2, 2, 3, 1],
    [2, 3, 1, 3],
    .
    .
    .
    [2, 2, 0, 1]], dtype=uint8)


    In this case, the k value would be 4



    Any additional improvement in the code is well received!
    Thanks for your time.










    share|improve this question









    $endgroup$















      1












      1








      1





      $begingroup$


      I have a Numpy function that takes the values of an existing array X and a size (int) k equivalent to the columns of the array. This function does some calculations in a new array, to finally output the new array after the calculations are done.



      def ff(x, k):
      newarr = np.zeros((x.shape[0], 1), dtype=np.uint32)
      newarr[:, 0] = x[:, 0] * 4
      for i in range(1, k - 1):
      newarr[:, 0] += x[:, i]
      newarr[:, 0] = newarr[:, 0] * 4
      newarr[:, 0] += x[:, -1]
      return newarr


      newarr it's the array where the calculated data is stored, it's initialized with np.zeros and a dtype, and it has a shape of (y,1) where y is the length of the x array.



      The first step is to store in the (only) column of the newarr the multiplication of the first column of the x by 4.



      The iteration occurs over the columns 1 to k-1 of the original array (x).
      Inside the iteration, the next step is to sum the values of the first column of x to the column of newarr.
      Next, to multiply the column of newarr by 4
      To finally, after the iteration is complete, sum the last column of the original array x to the column of newarr.



      I'm looking for a way (if there's any) to avoid the creation of the newarr, and do the calculations in the original array. This', to reduce the memory usage of this function, mainly because the x tends to be very big in execution.



      The x array looks like this.



      array([[3, 3, 0, 1],
      [3, 0, 1, 0],
      [0, 1, 0, 2],
      [1, 0, 2, 2],
      [0, 2, 2, 3],
      [2, 2, 3, 1],
      [2, 3, 1, 3],
      .
      .
      .
      [2, 2, 0, 1]], dtype=uint8)


      In this case, the k value would be 4



      Any additional improvement in the code is well received!
      Thanks for your time.










      share|improve this question









      $endgroup$




      I have a Numpy function that takes the values of an existing array X and a size (int) k equivalent to the columns of the array. This function does some calculations in a new array, to finally output the new array after the calculations are done.



      def ff(x, k):
      newarr = np.zeros((x.shape[0], 1), dtype=np.uint32)
      newarr[:, 0] = x[:, 0] * 4
      for i in range(1, k - 1):
      newarr[:, 0] += x[:, i]
      newarr[:, 0] = newarr[:, 0] * 4
      newarr[:, 0] += x[:, -1]
      return newarr


      newarr it's the array where the calculated data is stored, it's initialized with np.zeros and a dtype, and it has a shape of (y,1) where y is the length of the x array.



      The first step is to store in the (only) column of the newarr the multiplication of the first column of the x by 4.



      The iteration occurs over the columns 1 to k-1 of the original array (x).
      Inside the iteration, the next step is to sum the values of the first column of x to the column of newarr.
      Next, to multiply the column of newarr by 4
      To finally, after the iteration is complete, sum the last column of the original array x to the column of newarr.



      I'm looking for a way (if there's any) to avoid the creation of the newarr, and do the calculations in the original array. This', to reduce the memory usage of this function, mainly because the x tends to be very big in execution.



      The x array looks like this.



      array([[3, 3, 0, 1],
      [3, 0, 1, 0],
      [0, 1, 0, 2],
      [1, 0, 2, 2],
      [0, 2, 2, 3],
      [2, 2, 3, 1],
      [2, 3, 1, 3],
      .
      .
      .
      [2, 2, 0, 1]], dtype=uint8)


      In this case, the k value would be 4



      Any additional improvement in the code is well received!
      Thanks for your time.







      python-3.x numpy






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      asked 5 hours ago









      KakoKako

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