Implementation note: Unrolling parameters

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Implementation note: Unrolling parameters
  • Advanced optimization to unroll parameter from matrices into vectors

theta becomes vector, not a single unit

  • unroll so advanced optimization can receive vectors of theta as an input

  • Reshape: takes number of elemen from a vector, 1:110 (Because theta1 = 10x11) and reshape as one matrices with 10x11 shape

  • so that's it for matrix vs vector representation
  • Advantage matrices: more convenient forward back prop for vectorized implementation
  • Advantage vector = vectorized assume dvec,thetavec as just one big vector