dseuss/mpnum

\directlua{mpt.defaults['len_horizontal_legs'] = 1}

\directlua{mpt.draw_node({}, {x=-2.5, tensor_name='c'})}
\node at (c) {$c$};

\node at (0,0) {\Huge $=$};

\directlua{mpt.draw_node({E=1}, {x=2.5, tensor_name='u'})}
\node at (u) {$u^\ast_i$};

\directlua{mpt.draw_node({W=1, E=1}, {x=5.5, tensor_name='A', tensor_width=1.5})}
\node at (A) {$A_{ij}$};
\node [anchor=north] at (A_W1e) {$i$};
\node [anchor=north] at (A_E1e) {$j$};

\directlua{mpt.draw_node({W=1}, {x=8.5, tensor_name='v'})}
\node at (v) {$v_j$};