Array Operations

The previous section described standard linear algebra matrix operations. Alternatively, element-by-element matrix arithmetic is provided by array operations. An array operator is formed by preceding one of the symbols +, -, *, \, or / by a period (.). Of course, the matrix and array operators for addition and subtraction are equivalent, and + and - are used in either case.

The operator .* denotes array multiplication and is defined whenever the two operands have the same dimensions. For example
>> A=[1 2 3; 4 5 6] ; B = [2 2 2; 3 3 5]; C=A.*B
results in

C =
     2     4     6
    12    15    30

Similarly, A.\B and A./B provide the left and right element-by-element division. Raising each element of a matrix to the same power is accomplished by the .^ operator.

Most standard MATLAB functions operate on a matrix element-by-element. For example
>> cos(C)

ans =
  -4.1615e-01  -6.5364e-01   9.6017e-01
   8.4385e-01  -7.5969e-01   1.5425e-01

If you create your own functions (See Section 11.) you should keep in mind that MATLAB assumes that a matrix (or a vector) can be passed to it.