rft(rx [,divbyT:T]), rx a REAL matrix |

rft(rx) where rx is a REAL vector or matrix, computes the Hermitian form of the complex discrete Fourier transform of each column of rx, considered as a real series. Any MISSING values in rx are replaced by 0 in computing the result and a warning message is printed. rft(rx,divbyt:T) does the same except the result is divided by the number of rows of rx. hft(hconj(hx),divbyt:T) is the inverse of rft() in the sense that rx and hft(hconj(rft(rx)),divbyt:T) are equal except for rounding error. The largest prime factor of nrows(rx) must not exceed 29. You can use primefactors() to find the maximum factor of nrows(rx) and goodfactors() to find a length >= nrows(rx) which has no prime factors > 29. In addition, the product of all the "unpaired" prime factors can't be too large. For example N = 3*5*7*11*13*17*M^2 = 255255*M^2, where M is an integer, breaks the algorithm and hence is not allowed. See topic 'complex' for discussion of complex matrices in MacAnova. See also cft(), hft(), hconj(), primefactors(), goodfactors().

Gary Oehlert 2003-01-15