Compute the theoretical autocorrelation function for an ARMA process.
ARMAacf_cpp(ar,ma,lag_max)x A matrix listing values from 1...nx in one column and 1...1, 2...2,....,n...n, in the other
A vector of length p containing AR coefficients
A vector of length q containing MA coefficients
A unsigned integer indicating the maximum lag necessary
JJB
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.