Compute the theoretical autocorrelation function for an ARMA process.
ARMAacf_cpp(ar,ma,lag_max)A vector of length p containing AR coefficients
A vector of length q containing MA coefficients
A unsigned integer indicating the maximum lag necessary
x A matrix listing values from 1...nx in one column and 1...1, 2...2,....,n...n, in the other
This is an implementaiton of the ARMAacf function in R. It is approximately 40x times faster. The benchmark was done on iMac Late 2013 using vecLib as the BLAS.