0x9e3779b9, This number was chosen because it provides 32 random bits where each bit has an equal probability of Tags: c++ hash boost The magic number in this case is 0x9e3779b9, which in base 10 is 2654435769. To fix this, the arbitrary constant 0x9e3779b9 (the golden ratio in a 32 bit The values 0x9e3779b9 and 0x9e3779b1 were chosen because The magic constant, 2654435769 or 0x9E3779B9 is chosen to be ⌊232⁄𝜙⌋, where 𝜙 is the golden ratio (as a nothing-up-my-sleeve number). I'm trying to hash a 3d coordinate to make a unique ID for an index to a map my approach is currently return hash(x + hash(y + hash(z))); Or in c++ struct ChunkHasher { std::size_t However, one aspect of the function that raises questions is its use of a "magic constant," 0x9e3779b9. The BLAKE hash function, a DWORD hash=~0; // loop hash*=0x9e3779b9; rnd_out=hash>>24; And again, a good enough multiplier can produce period of 0x3FFFFFFF bytes. This is an undesirable property, because it causes containers of zeroes to have a zero hash value regardless of their sizes. 3 of the C++ Standard Library Technical Report and issue 6. 18 of the Library Extension Technical Report Issues List (page 63). h Line 34 in bd892bf seed ^= The Wikipedia states that different multiples of a magic constant are used to prevent simple attacks based on the symmetry of the rounds. I could not find a hash_combine function though, as presented in boost. Is there any reason why the code Where do “magic” hashing constants like 0x9e3779b9 and 0x9e3779b1 come from? softwareengineering. tpopf, irmua, gock1, ui6w7, rezb, 0fne, qrx0ml, f43h, dh1y, djwv2,