In computational mathematics, the Hadamard ordered fast Walsh–Hadamard transform (FWHTh) is an efficient algorithm to compute the Walsh–Hadamard transform would have a computational complexity of n^2). The FWHTh additions or subtractions.

The FWHTh is a divide-and-conquer algorithm that recursively. Hadamard matrix:

normalization factors for each stage may be grouped together or even omitted.

The sequency-ordered, also known as Walsh-ordered, fast Walsh–Hadamard transform, FWHTw, is obtained by computing the FWHTh as above, and then rearranging the outputs.

, where A is m.

Python example code

See also

• Fast Fourier transform

• Fast wavelet transform

References

External links

• Charles Constantine Gumas, A century old, the fast Hadamard transform proves useful in digital communications