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The transpose (indicated by T) of any row vector is a column vector, and the transpose of any column vector is a row vector: […] = [] and [] = […]. The set of all row vectors with n entries in a given field (such as the real numbers ) forms an n -dimensional vector space ; similarly, the set of all column vectors with m entries forms an m ...
If the vector spaces X and Y have respectively nondegenerate bilinear forms B X and B Y, a concept known as the adjoint, which is closely related to the transpose, may be defined: If u : X → Y is a linear map between vector spaces X and Y , we define g as the adjoint of u if g : Y → X satisfies
In Matlab/GNU Octave a matrix A can be vectorized by A(:). GNU Octave also allows vectorization and half-vectorization with vec(A) and vech(A) respectively. Julia has the vec(A) function as well. In Python NumPy arrays implement the flatten method, [note 1] while in R the desired effect can be achieved via the c() or as.vector() functions.
The matrix and the vector can be represented with respect to a right-handed or left-handed coordinate system. Throughout the article, we assumed a right-handed orientation, unless otherwise specified. Vectors or forms The vector space has a dual space of linear forms, and the matrix can act on either vectors or forms.
The conjugate transpose of a matrix with real entries reduces to the transpose of , as the conjugate of a real number is the number itself. The conjugate transpose can be motivated by noting that complex numbers can be usefully represented by 2 × 2 {\displaystyle 2\times 2} real matrices, obeying matrix addition and multiplication:
In other words, vec(A) is the vector obtained by vectorizing A in column-major order. Similarly, vec( A T ) is the vector obtaining by vectorizing A in row-major order. In the context of quantum information theory , the commutation matrix is sometimes referred to as the swap matrix or swap operator [ 1 ]
In [5] are given as examples code of a Matlab functions that creates and matrices for vector of size n = 2, 4, or, 8. Stay open question is it possible to create T r s {\displaystyle Trs} matrices of size, greater than 8.
Visual understanding of multiplication by the transpose of a matrix. If A is an orthogonal matrix and B is its transpose, the ij-th element of the product AA T will vanish if i≠j, because the i-th row of A is orthogonal to the j-th row of A. An orthogonal matrix is the real specialization of a unitary matrix, and thus always a normal matrix.