说明：  The function implement the 1D sequency(Walsh) ordered fast Walsh-Hadamard transform which can be used in signal processing, pattern recongnition and Genetic alogorithms. This algorithm uses a Cooley-Tukey type signal flow graph and is implemented in N log2 N additions and subtractions. Data sequence length must be an integer power of 2. The inverse transform is the same as the forward transform except for the multiplication factor N. This can be easily achieved by deleting the last line i.e. x=inv(N)*x Example: x=[1 2 1 1] W=FWHT(x)