MATLAB Function Reference |
Syntax
Description
C = A
*B
is the linear algebraic product of the matrices A
and B
. If A
is an m-by-p and B
is a p-by-n matrix, the i,j
entry of C
is defined by
The product C
is an m-by-n matrix. For nonscalar A
and B
, the number of columns of A
must equal the number of rows of B
. You can multiply a scalar by a matrix of any size.
The preceding definition says that C(i,j)
is the inner product of the i
th row of A
with the j
th column of B
. You can write this definition using the MATLAB colon operator as
where A(i,:)
is the i
th row of A
and B(:,j)
is the j
th row of B
.
Note
If A is an m-by-0 empty matrix and B is a 0-by-n empty matrix, where m and n are positive integers, A*B is an m-by-n matrix of all zeros.
|
Example 1
If A
is a row vector and B
is a column vector with the same number of elements as A
, A*B
is simply the inner product of A
and B
. For example,
Example 2
Note that the second row of A is
while the third column of B is
The inner product of A(2,:)
and B(:,3)
is
Algorithm
mtimes
uses the following Basic Linear Algebra Subroutines (BLAS):
For inputs of type single
, mtimes using corresponding routines that begin with "S
" instead of "D
".
See Also
msgbox | mu2lin |
© 1994-2005 The MathWorks, Inc.