of D G so the total number of multiplications for this kernel is d G times D G times M so for some n kernels will have n times D G times D G times M such multiplications and thus the total number of multiplications is the sum of multiplications in the depth wise convolution stage plus the number of multiplications in the point-wise convolution stage we can take M times D G squared common now we compare the standard convolution with depth wise convolution we get the ratio as the sum of reciprocal of the depth of output