Main Program: Initialization

Next, we initialize the pseudorandom number generator r by setting the seed value using Seed. Then the number of spins $N$ is computed assuming a square magnet. We then allocate memory needed to hold the magnet; this is a standard method of allocating a 2D array of integers. Next we call our init() function, and finally we convert $T$ to $1/T$ since multiplication is more efficient than division.

  /* Seed the random number generator */
  gsl_rng_set(r,Seed);

  /* Compute the number of spins */
  N=L*L;

  /* Allocate memory for the system */
  M=(int**)malloc(L*sizeof(int*));
  for (i=0;i<L;i++) M[i]=(int*)malloc(L*sizeof(int));

  /* Generate an initial state */
  init(M,L,r);

  /* For computational efficiency, convert T to reciprocal T */
  T=1.0/T;