Re: Symmetrizing function arguments
- To: mathgroup at smc.vnet.net
- Subject: [mg127617] Re: Symmetrizing function arguments
- From: Hauke Reddmann <fc3a501 at uni-hamburg.de>
- Date: Wed, 8 Aug 2012 21:31:59 -0400 (EDT)
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Nasser M. Abbasi <nma at 12000.org> wrote: > On 8/7/2012 2:04 AM, Hauke Reddmann wrote: >> g[a_,b_,c_]:=If[b>c,If[a>c,If[a>b,G[a,b,c],g[b,a,c]],g[c,b,a]],g[a,c,b]]; > why not simply use Sort, that is what you are doing above? a) because I am a n00b :-), but more relevant b): these were examples, but the actual 6j symbols are NOT invariant under Sort, just under tetrahedral symmetry! I.e. 6j[a,b,c,d,e,f]=6j[c,d,a,b,e,f] (and likewise for the third pair e,f) and 6j[a,b,c,d,e,f]=6j[a,b,d,c,f,e] (and likewise all other double swaps). So applying Sort correctly is not that trivial. -- Hauke Reddmann <:-EX8 fc3a501 at uni-hamburg.de Out on deck the dawn arrived Your grey sweater oversized The rooftops glimmered before our eyes