I have two question on the Relu activation function:
- Normally, the Relu function is a straight line on the left and rise to the right. But I guess that shape can rotate to any angel by different w and b like a linear function? But can the straight line part on the right side instead of always on the left side like the 4 little relu shapes in the screenshot?
- I don’t understand why the 4 Relu lines can connect to one another seamlessly at the two ends?
- Can I say the final composite Relu line is taking each component of small Relu one by one like the colored screenshot? If so, why the green part is rising instead of downward like the green one at the bottom?
Hi @flyunicorn
Yes, the ReLU shape can effectively shift or rotate depending on the weight and bias—it’s still the same function (0 for negative input, linear for positive), but weights and biases move the activation threshold left or right. So the flat (zero) part can appear on the right side instead of the left, depending on those values.
The reason the individual ReLU lines appear to connect seamlessly in the final output is not because they are stitched together one by one, but because they are all applied in parallel and their outputs are summed. Each ReLU unit activates at different input ranges, and together they form a piecewise linear approximation.
So no, the final curve doesn’t follow each colored ReLU one after another—it adds them all up at each point. That’s why the green part of the final curve can be rising, even if the green ReLU unit alone slopes downward—other units are contributing stronger positive values at that point.
Hope it helps! Feel free to ask if you need further assistance.
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