GAMS has these random number generator functions:
num = uniform(low,high): Uniform random number between
num = uniformint(low,high): Uniform integer random number between
num = normal(mean,std): Random number from a normal distribution with a mean of mean and a standard deviation of std
The random numbers in GAMS are not truly random, they are pseudo-random, generated using a deterministic algorithm (called a generator) inside GAMS. If you want different random numbers on each run, you must reseed the generator.
You may use something like:
execseed = 1 + gmillisec(jnow);