This is part of DE-MCMC algorithm. This function generates a gamma vector
for element-wise computation in Armadillo C++. This function is based on
p242 ter Braak (2006) who cited Roberts and Rosenthal (2001)
Usage
GetGamma(npar, gammamult, hyper = FALSE)
Arguments
npar
number of parameters.
gammamult
a tuning parameter stands for for gamma mutation. Default
value is 2.38.
hyper
a boolean switch, indicating to calculate hyper gamma