16 Feb
2005
16 Feb
'05
3:47 p.m.
Hi, I am new in Ginac,and have a stupid question. I dont know how to get all possible permutations of the four index pairs (sigma, l), (mu,m), (nu,n) and (rho,o). (Its a QCD vertex...) in the expression: ex four = color_f(a,b,c)*color_f(a,d,e)*(delta_tensor(l,b)*delta_tensor(m,c)*d elta_tensor(n,d)*delta_tensor(o,e)*metric_tensor(alpha,sigma)*metric_tensor(beta ,mu)*metric_tensor(nu,alpha.toggle_variance())*metric_tensor(beta.toggle_varianc e(),rho): I can make somethink like four.symmetrize((sigma,l),(mu,m),(nu,n),(rho,o))? I've looked at the archives and didn t find. Thanks a lot, Marco ------------------------------------------------- This mail sent through IMP: http://horde.org/imp/