** ( ) Parentheses are used to indicate precedence in arithmetic **

** expressions and to enclose arguments of functions in the **

** usual way. They are used to enclose subscripts of vectors **

** and matrices in a manner somewhat more general than the **

** usual way. If X and V are vectors, then X(V) is **

** [X(V(1)), X(V(2)), ..., X(V(N))]. The components of V **

** are rounded to nearest integers and used as subscripts. An **

** error occurs if any such subscript is less than 1 or **

** greater than the dimension of X. Some examples: **

** X(3) is the third element of X. **

** X([1 2 3]) is the first three elements of X. So is **

** X([ SQRT (2), SQRT (3), 4*ATAN (1)]). **

** If X has N components, X(N:-1:1) reverses them. **

** The same indirect subscripting is used in matrices. If V **

** has M components and W has N components, then A(V,W) **

** is the M-by-N matrix formed from the elements of A whose **

** subscripts are the elements of V and W. For example... **

** A([1,5],:) = A([5,1],:) interchanges rows 1 and 5 of A. **

** **

** **

** [ ] Brackets are used in forming vectors and matrices. **

** [6.9 9.64 SQRT (-1)] is a vector with three elements **

** separated by blanks. [6.9, 9.64, sqrt(-1)] is the same **

** thing. [1+ I 2-I 3] and [1 +I 2 -I 3] are not the same. **

** The first has three elements, the second has five. **

** [11 12 13; 21 22 23] is a 2-by-3 matrix. The semicolon **

** ends the first row. **

** Vectors and matrices can be concatenated with [ ] brackets. **

** [A B; C] is allowed if the number of rows of A equals **

** the number of rows of B and the number of columns of A **

** plus the number of columns of B equals the number of **

** columns of C. This rule generalizes in a hopefully **

** obvious way to allow fairly complicated constructions. **

** A = [ ] stores an empty matrix in A. See CLEAR to remove **

** variables from the current workspace. **

** For the use of [ and ] on the left of the = in multiple **

** assignment statements, see LU , EIG , SVD and so on. **

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

** **