Tensors for matrix differentiation
نویسنده
چکیده
Let’s setup one useful form of tensor notation, which incorporates the matrix and inner product, the outer product, the Hadamard (MATLAB .* or ◦) product diag and diag−1. These will be denoted using different combinations of pairs of up-stairs and down-stairs indices. If we have only 2 order tensors (and lower) we want to be able to easily convert the result into matrix representation. We have a free choice for the horizontal ordering of indices therefore this can be used to denote transposes and the order of multiplication.
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