# Compute PI in an inefficient way
import strutils, math, threadpool
{.experimental: "parallel".}

proc term(k: float): float = 4 * math.pow(-1, k) / (2*k + 1)

proc pi(n: int): float = #new process, int in and float out
  var ch = newSeq[float](n+1) #create n long sequens of type float
  parallel:
    for k in 0..ch.high: #0..ch.high is a range, 0 to highest index
      ch[k] = spawn term(float(k)) # spawn for every index
  for k in 0..ch.high: #loop a range
    result += ch[k] # results from every spawn is added to results

echo formatFloat(pi(5000)) #runs pi, formats the answer and prints it