primes with ulam spiral corner limit

primes_ulam_corner_limit.groovy

def init = System.currentTimeMillis()
for(N = 9; N < 530; N+=2) {
  println "${N} -> ${isOddCompositeNumber(N) ? '' : '__prime__'}"
}

def isOddCompositeNumber(double N) {
  def U = Math.floor(Math.sqrt((N - 1 + Math.floor(Math.sqrt(N - 4) + 1)) / 4) - 1)
  def t = false;
  for(i = 0; i <= U; i++) {
    def B = (i * 4) + 6;
    def Q = (N / B) % 0.5;
    t = Q == 0
    if(t) {
      break
    }
  }
  return t;
}

def end = System.currentTimeMillis()
println "T: ${(end - init) / 1000}s"


/*
for(x = 2; x < 10000; x++) {
  //4x2 - 2x + 1
  def a = 4
  def b = - 2
  def c = 1

  def y = a * Math.pow(x, 2) + b * x + c
  assert y - c == a * Math.pow(x, 2) + b * x
  assert y - c == (a * Math.pow(x, 2) + b * x)
  assert y - c == x * ((a * x) + b)
  assert y - c == x * ((a * x) + b)


  def p1 = Math.sqrt((y - 1 + Math.floor(Math.sqrt(y - 4) + 1)) / 4)
  def p2 = x
  assert p1 == p2
  //println "    *** ${p1} == ${p2} ?? ${p1 - p2}"


  println "${y} -> [${x}]"
}
/**/