Using the C++ Math Library

Using N-Dimensional Subscripts

This section describes how to:

• Extract a scalar from a matrix
• Extract a vector from a matrix
• Extract a subarray from a matrix
• Extend two-dimensional indexing to N-dimensions

There is no functional difference between two-dimensional indexing and N-dimensional indexing (where N > 2). Because it is easier to understand two-dimensional arrays, most of the examples in this section deal with two-dimensional arrays. See Extending Two-Dimensional Indexing to N Dimensions to learn how to work with arrays of dimension greater than two.

All two-dimensional examples work with example matrix A.

1 4 7
2 5 8
3 6 9

Selecting the Entire Matrix As a Column Vector

Overview