Re: TensorRank

*To*: mathgroup at smc.vnet.net*Subject*: [mg9033] Re: [mg8977] TensorRank*From*: seanross at worldnet.att.net*Date*: Wed, 8 Oct 1997 00:05:30 -0400*Sender*: owner-wri-mathgroup at wolfram.com

Julian Stoev wrote: > > Dear Group, > I am not 100% sure, but I am using TensorRank as a function to determine a > rank of a matrix. > The folowing result is surprising for me. > The determinant<>0, but rank is defficient. > Am I wrong to use TensorRank in this way? > Thank you! > > In[1]:= > cm={{0, 0, 0, 1/j}, {0, 0, -(1/j), 0}, {0, k/(i*j), 0, -(k/j^2)}, > {-(k/(i*j)), 0, > k/j^2, 0}} > TensorRank[cm] > Det[cm] > Out[1]= > 1 1 k k k k > {{0, 0, 0, -}, {0, 0, -(-), 0}, {0, ---, 0, -(--)}, {-(---), 0, --, 0}} > j j i j 2 i j 2 > j j > Out[2]= > 2 > Out[3]= > 2 > k > ----- > 2 4 > i j > ------------------------------------------------------------------------ I don't understand the problem you are having. cm is a 4x4 matrix so it is a second rank tensor, which is exactly what TensorRank[cm] returns. What would you like TensorRank to return? Perhaps you want the dimensions of cm instead? Dimensions[cm] returns {4,4}