Re: Quaternion problem-> conversion

*To*: mathgroup at smc.vnet.net*Subject*: [mg67458] Re: Quaternion problem-> conversion*From*: Roger Bagula <rlbagula at sbcglobal.net>*Date*: Mon, 26 Jun 2006 00:13:00 -0400 (EDT)*References*: <e7ap5q$952$1@smc.vnet.net> <e7lf1d$3l9$1@smc.vnet.net>*Sender*: owner-wri-mathgroup at wolfram.com

I realize some people would rather use the Mathematica system quaternions. My answer is that Matrix quaternions can be converted to system quaternions as long as you haven't done something strange to them , like adding {{1,0},{0,0,}} or somthing else out of symmetry. << Algebra`Quaternions` i = {{0, 1}, {-1, 0}}; j = {{0, I}, {I, 0}}; k = {{I, 0}, {0, -I}}; e = IdentityMatrix[2]; q[t_, x_, y_, z_] := e*t + x*i + j*y + k*z; q[-1/2, 1/2, 1/2, 1/2].q[-1/2, -1/2, -1/2, -1/2] qM[a_, b_, c_, d_] := Quaternion[Re[q[a, b, c, d][[1, 1]]], Re[ q[a, b, c, d][[1, 2]]], Re[q[a, b, c, d][[1, 2]]], Im[q[a, b, c, d][[1, 1]]]] qM[-1/2, 1/2, 1/2, 1/2] ** qM[-1/2, -1/2, -1/2, -1/2] > > >