Small Low-Depth Circuits for the Walsh-Hadamard Transform
Speaker: JoshTitle: Small Low-Depth Circuits for the Walsh-Hadamard Transform
Date: 18 Feb 2021 17:00-18:00 EST
Location: Zoom
Food: Self-prepared
Abstract: The Walsh-Hadamard transform (WHT) is a discrete version of a Fouriter transform. Similar to the fast Fourier transform, one can compute the WHT of a length-N vector with a circuit of size O(N log N) and depth O(log N). What if you want a circuit with smaller depth? That construction generalizes to a depth-d circuit of size O(d * N^{1 + 1/d}). I’ll tell you about a new general framework for constructing smaller circuits, including a new smaller construction of size only O(d * N^{1 + 0.96/d}) that makes use of low-rank approximations of the WHT. No background about the WHT will be needed to enjoy this talk!