FUNCTION: LieTools/E2G
USAGE: E2G(i);
SYNOPSIS: E2G converts the labeling of roots by integers in {-nprts,...,-1,0,1, .. nprts}
  to the integers between 1 and dimg corresponding to the corresponding Cartan-Weyl basis
  vector.  
CAVEATS: requires a previously initialized global Lie algebra environment.
  (See LieTools[gSetup].)
EXAMPLE: 
> LieTools[gSetup](G,2);
Setting up Gtype = G   rnk = 2

> LieTools[E2G](1);

                                  9

> LieTools[E2G](-1);

                                  6

> LieTools[E2G](-6);

                                  1

SEE ALSO: LieTools[G2E], LieTools[E2R], LieTools[R2E]
