Karplus-Strong Pluck String

When the delay-line initial conditions consist of white noise, the algorithm is known as the Karplus-Strong algorithm.

White noise is a sequence of uncorrelated random values. It can be generated in Matlab as follows:

N = ...;         % length of vector

y = randn(1, N); % N samples of Gaussian white noise
                 % with zero mean and unit variance
                  
x = rand(1, N);  % N samples of white noise,
                 % uniform between 0 and 1

xn = 2*(x-0.5);  % uniform between -1 and 1

Filling the delay line with white noise is akin to plucking the string with a random initial displacement--a very energetic excitation.

What are the control parameters of this model?