Fast algorithms to QR factor circulant matrices
C.J. Demeure, Louis L. Scharf · International Conference on Acoustics, Speech, and Signal Processing · 2003
The authors introduce a fast algorithm for computing the QR factors of a complex vertically circulant matrix C. The complexity of the algorithm is 5mn+2n/sup 2/+O(m) complex-fixed point operations or 3mn+n/sup 2/+O(m) complex floating-point operations, where m is the number of rows in C and n is the number of columns (it is supposed that m>