Erlang B Equation - Traffic units and busy probability on GSM gateways

erlang-b.js

// Javascript: Percentage of busy
// calls with a=traffic and n lines

function erl(a,n)
{ 
  u=1;
  for(i=1;i<=n;i++)
  {
    u+=power(a,i)/factorial(i);
  }
  return((power(a,n)/factorial(n))/u+0.005)*100
}

function factorial(i) // Get factorial of i
{ 
  k=1;
  for (j=1; j<=i; j++)
  {
    k*=j;
  }
  return k
}

function power(k,i) // Compute k power i
{ 
  w=1;
  for (j=1; j<=i; j++)
  {
    w*=k;
  }
  return w
}