Important: The linalg package has been deprecated. Use the superseding commands, LinearAlgebra[MatrixMatrixMultiply] and LinearAlgebra[MatrixVectorMultiply], instead.

- For information on migrating linalg code to the new packages, see examples/LinearAlgebraMigration.

The function multiply(A, B,...) calculates the matrix product A B ... .  The dimensions of each matrix must be consistent with the rules of matrix multiplication.

The call multiply(A, v), for a matrix A and vector v, calculates the matrix-vector product A v. The number of entries in v must be equal to the number of columns of A. Thus if A is an n x m matrix, vectdim(v) must be m. The result is a vector with n entries.

The evalm command provides an easy method of accessing multiply.

The command with(linalg,multiply) allows the use of the abbreviated form of this command.

$\mathrm{with}\left(\mathrm{linalg}\right)\:$

$A≔\mathrm{array}\left(\left[\left[1\,2\right]\,\left[3\,4\right]\right]\right)\:$

$B≔\mathrm{array}\left(\left[\left[0\,1\right]\,\left[1\,0\right]\right]\right)\:$

$C≔\mathrm{array}\left(\left[\left[1\,2\right]\,\left[4\,5\right]\right]\right)\:$

$\mathrm{multiply}\left(A\,B\,C\right)$

$\left[\begin{array}{cc}6& 9\\ 16& 23\end{array}\right]$

$v≔\mathrm{vector}\left(\left[3\,4\right]\right)\:$

$\mathrm{multiply}\left(A\,v\right)$

$\left[\begin{array}{cc}11& 25\end{array}\right]$

$\mathrm{multiply}\left(v\,\mathrm{transpose}\left(v\right)\right)$

$\left[\begin{array}{cc}9& 12\\ 12& 16\end{array}\right]$