Matrix Dimensions Confusion

Hello Saif,

I think this screenshot is an example that can answer your first question:

  • shape of any W and any b has nothing to do with the # samples or # columns in X. (Shouldn’t this be reasonable? Because otherwise we can’t just input any number of samples for prediction)

  • X, A, Z always share the same # columns. (A sample is always represented in the same column number, that’s cool isn’t that?)

Can you match out all the shapes (of W1 b1 A1 Z1 W2 b2 A2 Z2) given the help of the example in my screen shot, and my above two points?

For your 2nd question, I hope we can discuss after we are done with the 1st question.

Cheers,
Raymond

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