Dear developers of the tensor module
The usage string of tensorhead(name, typ, sym, comm=0) [1] states:
sym : same as ``*args`` in ``tensorsymmetry``
but to me it should read
sym : same as ``args`` in ``tensorsymmetry``
see e.g. line 2171 of the same file, where one calls tensorsymmetry(*sym), with sym unpacked.
Examples of valid calls for the same symmetry specified with Young tableaux:
tensorsymmetry( [1,1,1], [2] )
tensorhead( 'T', [Lorentz]*5, [ [1,1,1], [2] ] )
while tensorsymmetry( [ [1,1,1], [2] ] ) does not work. (I must say that as a user I would prefer to have this latter syntax to have a homogeneous interface.)
I add that the doc for tensorhead seems not shown in the HTML interface [2].
regards
ric
[1]
https://github.com/sympy/sympy/blob/master/sympy/tensor/tensor.py#L2154
[2]
http://docs.sympy.org/dev/_modules/sympy/tensor/tensor.html