Stride changes the top-left starts where the given kernel lands. This lesson uses a separate exact image and recomputes only the selected stride-two cells.
highlighted = computed this step
Stride is the step size
This separate demo uses a 5 by 5 image, a 2 by 2 given kernel, valid padding, and stride 2. Stride changes where the kernel lands, not the dot-product arithmetic.
valid padding,stride 2
Selected starts
Stride 2 uses rows 0 and 2, and columns 0 and 2. Starts at row or column 1 are skipped because the step size is 2.
starts (0,0),(0,2),(2,0),(2,2)
Compute one selected cell
At start row 0, col 2, the exact dot product is 1·2 + 0·0 + 0·0 + 1·1 = 3.
1⋅2+0⋅0+0⋅0+1⋅1=3
The stride-two feature map
Recompute only at the selected starts. The exact stride 2 feature map is [[2, 3], [3, 2]]. This is exact forward-pass arithmetic only; the kernel is given, with NOT training and NOT learning.