thomaskoopman

4 ms·

1. 1.▲
   Show HN: FFTN, faster than FFTW in 700 lines of C(gitlab.sac-home.org)

   7 points by thomaskoopman 1y ago|0 comments
2. 2.▲
   by thomaskoopman 1y ago

   Quaternions (when viewed as vectors) are not linear functions, but the arguments to linear functions. You can add them: (a + bi + cj + dk) + (a' + b'i + c'j + d'k) = (a + a') + (b + b')i + (c + c')j + (d +
3. 3.▲
   by thomaskoopman 1y ago

   Yes, but quaternions of unit length are a representation of the rotation group in 3D space ( https://en.wikipedia.org/wiki/Representation_theory_of_SU(2)... ), which is how they are used for rotations.
4. 4.▲
   by thomaskoopman 1y ago

   Very cool, fast and looks like it should vectorize too. Do you have a jump function for parallel seeding? How did you come up with this, some number-theoretic basis or more experimental?
5. 5.▲
   by thomaskoopman 1y ago

   A matrix is a representation of a linear function (e.g. a function that plays nice with + and scalar multiplication). A specific subset can be used to describe rotations in 3D space. Quaternions can (arguably) do this better. But quaternion
6. 6.▲
   by thomaskoopman 2y ago

   Do you have any tips for writing research papers in a more accessible way?
7. 7.▲
   by thomaskoopman 2y ago

   I think it depends more on the ratio between access time and how often you use the data. Adding two arrays that fit in L1 is already limited by access time. On Zen3, we can add two 32-byte vectors per cycle, but only store one of these per