Editing Bit array (section)

=== Population / Hamming weight ===
If we wish to find the number of 1 bits in a bit array, sometimes called the population count or Hamming weight, there are efficient branch-free algorithms that can compute the number of bits in a word using a series of simple bit operations. We simply run such an algorithm on each word and keep a running total. Counting zeros is similar. See the [[Hamming weight]] article for examples of an efficient implementation.