method

indices

ruby latest stable - Class: Prime::EratosthenesSieve

indices(n)

private

for an odd number n, returns (i, j, k) such that @tables[i][j][k] represents primarity of the number

# File lib/prime.rb, line 460
    def indices(n)
      #   binary digits of n: |0|1|2|3|4|5|6|7|8|9|10|11|....
      #   indices:            |-|    k  |  j  |     i
      # because of NUMS_PER_ENTRY, NUMS_PER_TABLE

      k = (n & 0b00011111) >> 1
      j = (n & 0b11100000) >> 5
      i = n >> 8
      return i, j, k
    end

indices

Method deprecated or moved

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