Determine scale factors for rotated groups

Developers Ruby API
2 
tr=group.transformation.to_a
xscale = Math::sqrt(tr[0]*tr[0]+tr[1]*tr[1]+tr[2]*tr[2])
yscale = Math::sqrt(tr[4]*tr[4]+tr[5]*tr[5]+tr[6]*tr[6])
zscale = Math::sqrt(tr[8]*tr[8]+tr[9]*tr[9]+tr[10]*tr[10])