norm1 - 1-norm of a vector or element-wise 1-norm of a matrix
norm2 - Euclidean norm of a vector or Frobenius norm of a matrix
tr, det, logdet, inv
Common error messages:
Cannot display this 3rd/4th order tensor.
Only scalars, vectors, and matrices are displayed as output. If the derivative is a higher order tensor it will be computed but not displayed since there is no (good) representation of higher order tensors by matrices.
For instance, differentiating the matrix expression X with respect to the matrix X yields the 4th order identity tensor. It will not be displayed.
Cannot display this 2nd order tensor.
Some 2nd order tensors do not have a representation as a matrix. For instance, differentiating the row vector expression x' with respect to the column vector x yields a 2nd order tensor that has no representation as a matrix. In such cases try the transpose of the original input expression. It is a column vector and its derivative can be represented as a matrix.