Not sure if you saw this post I put into chat Brian. Not related to beta but very much a quaternion explanation.
There is a channel on youtube called 3blue1brown where Grant Sanderson does exceptional math videos. I have heard interest in quaternions expressed in the J community so I will put in some links that provide visual explanations of quaternions and how to visualize their actions across 4 dimensions. Initial video introducing quaternions: https://www.youtube.com/watch?v=d4EgbgTm0Bg Short video introducing an interactive tool to investigate quaternion behaviour: https://www.youtube.com/watch?v=zjMuIxRvygQ Site containing the interactive videos https://eater.net/quaternions (yes these videos are interactive and can be manipulated in real time!) Enjoy Cheers, bob > On Oct 30, 2018, at 3:15 PM, Brian Schott <[email protected]> wrote: > > Raul, > > I wish I understood quaternions, but since I don't, I can't help much. > > I see the following definition for qnf in quatern.ijs. So in what sense is > it NOT implemented, as you say? > > qnf=: 1 : 'qn1_mt_ (u@(j. qn1_mt_) ((9 o. [) qn1_mt_ (* 11&o.)~) (% > qn1_mt_)@]) qnmod_mt_@qnmarkijk_mt_ qn1_mt_ ]' > > On Tue, Oct 30, 2018 at 5:27 PM Raul Miller <[email protected]> wrote: > >> Currently, >> >> require'math/mt' >> 1 qn1_mt_ 0 0 >> 1 0 >> 1 qni_mt_ 0 0 >> 0j1 0 >> 1 qnj_mt_ 0 0 >> 0 1 >> 1 qnk_mt_ 0 0 >> 0 1 >> >> To fix, maybe we should change the definition of qnk to: >> >> qnk=: 11&o.@{: : ((j.~qnj) 1} ]) >> >> Also, sadly, the qnf mentioned at the bottom of the file does not seem >> to be implemented, though playing with taylor series suggests this >> might not be impossible to implement: >> >> +/((qnmul_mt_&1 0)^:(i.100) 1 0)%!i.100 >> 2.71828 0 >> +/((qnmul_mt_&0j1 0)^:(i.100) 1 0)%!i.100 >> 0.540302j0.841471 0 >> +/((qnmul_mt_&0 1)^:(i.100) 1 0)%!i.100 >> 0.540302 0.841471 >> +/((qnmul_mt_&0 0j1)^:(i.100) 1 0)%!i.100 >> 0.540302 0j0.841471 >> >> Thanks, >> >> -- >> Raul >> ---------------------------------------------------------------------- >> For information about J forums see http://www.jsoftware.com/forums.htm > > > > -- > (B=) <-----my sig > Brian Schott > ---------------------------------------------------------------------- > For information about J forums see http://www.jsoftware.com/forums.htm ---------------------------------------------------------------------- For information about J forums see http://www.jsoftware.com/forums.htm
