Hamming Weight

wiki

Difference (from prior minor revision) (major diff, author diff)

Changed: 7c7

hw_simple: 6.0E-06 6.0E-06 5.9E-06 s

hw_simple: 5.9E-06 5.9E-06 5.9E-06 s

Changed: 12,14c12,14

hw_lut8: 1.1E-06 1.1E-06 1.1E-06 s
hw_lut8a: 5.3E-07 5.4E-07 5.4E-07 s
hw_wegner: 3.0E-06 3.0E-06 3.0E-06 s

hw_lut8: 1.2E-06 1.2E-06 1.2E-06 s
hw_lut8a: 5.4E-07 5.4E-07 5.3E-07 s
hw_wegner: 2.9E-06 2.9E-06 2.9E-06 s

Changed: 17c17

hw_simple: 6.6E-08 6.6E-08 6.7E-08 s

hw_simple: 6.9E-08 6.9E-08 6.9E-08 s

Changed: 22,24c22,24

hw_lut8: 5.1E-08 5.3E-08 5.3E-08 s
hw_lut8a: 1.9E-08 1.9E-08 1.9E-08 s
hw_wegner: 6.1E-08 6.0E-08 6.1E-08 s

hw_lut8: 1.7E-09 1.7E-09 1.7E-09 s
hw_lut8a: 8.2E-09 8.2E-09 8.2E-09 s
hw_wegner: 6.0E-08 5.9E-08 5.9E-08 s

The hamming weight of a bitwise integer is the number of 1's in the binary representation [1].

Benchmark tests of various ways to calculate it are in [hamming_weight_test.lua]:

Lua 5.2.0/bit32, Intel Xeon, 2012-03-22
 hw_simple: 5.9E-06 5.9E-06 5.9E-06 s
 hw_dc2bit: 1.7E-06 1.7E-06 1.7E-06 s
 hw_dc3bit: 1.5E-06 1.5E-06 1.5E-06 s
 hw_dc4bit: 1.8E-06 1.8E-06 1.8E-06 s
    hw_dci: 1.7E-06 1.7E-06 1.7E-06 s
   hw_lut8: 1.2E-06 1.2E-06 1.2E-06 s
  hw_lut8a: 5.4E-07 5.4E-07 5.3E-07 s
 hw_wegner: 2.9E-06 2.9E-06 2.9E-06 s

LuaJIT 2.x/bit git2012-03-17, Intel Xeon, 2012-03-22
 hw_simple: 6.9E-08 6.9E-08 6.9E-08 s
 hw_dc2bit: 1.9E-09 1.9E-09 1.9E-09 s
 hw_dc3bit: 1.8E-09 1.8E-09 1.8E-09 s
 hw_dc4bit: 2.0E-09 2.0E-09 2.0E-09 s
    hw_dci: 1.8E-09 1.8E-09 1.8E-09 s
   hw_lut8: 1.7E-09 1.7E-09 1.7E-09 s
  hw_lut8a: 8.2E-09 8.2E-09 8.2E-09 s
 hw_wegner: 6.0E-08 5.9E-08 5.9E-08 s

(smaller is better)

Hamming Weight

See Also