Vectors and matrices are often referred to by the general term arrays. A vector is an array of 1 row x n columns (row vector) or 1 column x n rows (column vector), while a matrix is an array of m rows x n columns.
While ordinary variables hold a single value, arrays hold many values.
Functions that expect a vector argument generally require a column vector. You can create and use arrays in your calculations much like you would numbers or scalar variables.
Many general purpose operators and functions can be used with arrays, but there are also some special array operators for array manipulation:
• Index operator—Returns or assigns a particular element within an array.
• Row operator—Returns a matrix row.
• Column operator—Returns a matrix column.
• Transpose operator—Returns an n × m array formed by interchanging the rows and columns of an m × n array.
Contents of Arrays and Nested Arrays
Arrays can contain numbers, expressions, or strings. Arrays can also contain other arrays, in which case they are called nested arrays.
Matrix Size and Memory Management
Every matrix defined in your worksheet at the top level remains in memory until you close the worksheet. The most efficient way to use your computer memory when working with matrices is to preallocate matrices. This can be done by assigning the last element of a matrix to 0. This sets aside enough space in memory for the rest of the matrix. Dynamically assigning matrices, that is, filling them up from the smallest index to the largest, takes more computational time, and it can slow down your worksheet calculations.
The matrix size limit depends on the memory on your system. Approximately 8 bytes of memory are needed per matrix element. For most systems, the matrix limit is at least 1 million elements.
Every matrix defined in your worksheet remains in memory until the worksheet is closed.