examples/montecarlo.nit

   1 # This file is part of NIT ( http://www.nitlanguage.org ).
   2 #
   3 # Licensed under the Apache License, Version 2.0 (the "License");
   4 # you may not use this file except in compliance with the License.
   5 # You may obtain a copy of the License at
   6 #
   7 #     http://www.apache.org/licenses/LICENSE-2.0
   8 #
   9 # Unless required by applicable law or agreed to in writing, software
  10 # distributed under the License is distributed on an "AS IS" BASIS,
  11 # WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
  12 # See the License for the specific language governing permissions and
  13 # limitations under the License.
  14
  15 # Approximation of Pi using a Monte Carlo simulation.
  16 #
  17 # This is just an example of basic math and random operations.
  18 module montecarlo
  19
  20 # Number of iterations
  21 var n = 1000
  22 if args.not_empty then n = 2 ** args.first.to_i
  23
  24 # Threshold for output
  25 var j = 1
  26
  27 # Number of hits
  28 var h = 0
  29
  30 for i in [1..n] do
  31         # Random position in the ([0..1[,[0..1[) square
  32         var x = 1.0.rand
  33         var y = 1.0.rand
  34
  35         # Hit if in the circle
  36         if x*x + y*y <= 1.0 then h += 1
  37
  38         # Print
  39         if i >= j or i == n then
  40                 print "i={i} h={h} p={(4.0*h.to_f/i.to_f).to_precision(6)}"
  41                 j *= 2
  42         end
  43 end