ARITH

+   Plus.

X + Y adds matrices X and Y.  X and Y must have the same

dimensions unless one is a scalar (a 1-by-1 matrix).

A scalar can be added to anything.

-   Minus.

X - Y subtracts matrix X from Y.  X and Y must have the same

dimensions unless one is a scalar.  A scalar can be subtracted

from anything.

*   Matrix multiplication.

X*Y is the matrix product of X and Y.  Any scalar (a 1-by-1 matrix)

may multiply anything.  Otherwise, the number of columns of X must

equal the number of rows of Y.

.*  Array multiplication

X.*Y denotes element-by-element multiplication.  X and Y

must have the same dimensions unless one is a scalar.

A scalar can be multiplied into anything.

^   Matrix power.

Z = X^y is X to the y power if y is a scalar and X is square. If y is an

integer greater than one, the power is computed by repeated

multiplication. For other values of y the calculation

involves eigenvalues and eigenvectors.

Z = x^Y is x to the Y power, if Y is a square matrix and x is a scalar,

computed using eigenvalues and eigenvectors.

Z = X^Y, where both X and Y are matrices, is an error.

.^  Array power.

Z = X.^Y denotes element-by-element powers.  X and Y

must have the same dimensions unless one is a scalar.

A scalar can operate into anything.

Copyright (c) 1984-93 by The MathWorks, Inc.