If A and B are matrices of the same dimensions, A + B is a matrix of same dimension whose entries are the sums of the corresponding entries of A and B.
If either A or B is scalar (1 x 1 matrix), then the scalar is added to each entry of the other matrix.
If A is an matrix and B is row vector, when A+B is calcuated, the th element of B is added to each element of the th row of A.
Similarly, if A is an matrix and B is column vector, when A+B is calcuated, the th element of B is added to each element of the th column of A.
If the dimensions of A and B don't match in any of the ways described above, A + B will cause an error. For example
x = [-2.5, 3; 9, 7] -2.5 3 9 7 y = [1, -2; 3, -5] 1 -2 3 -5 z = x + y -1.5 1 12 2
If A and B are of the same storage type, then A + B is of the same type. Otherwise the type of the result is same as the one that needs more storage space. For example, if a double matrix and a integer matrix are added, the result is a double matrix.
Subtraction A - B is defined in the similar manner.
oz 2009-12-22