Function: math[mainDiagonal] - extracts the main diagonal from a square matrix

Calling Sequence:

mainDiagonal(A);

Parameters:

A - an array

Description:

mainDiagonal returns the main diagonal in the square matrix A.

The return is a list of all the elements on the main diagonal. If A is not a square matrix then mainDiagonal returns the empty list ([ ] or [ NULL ]).

This function is part of the math package, and so can be used only after performing the command with(math) or with(math, mainDiagonal).

Examples:

> with(math):

> A := matrix([[1, 2, 3], [4, 5, 6], [7, 8, 9]]);

[Maple Math]

> mainDiagonal(A);

[Maple Math]

> B := array(diagonal, 1 .. 2, 1 .. 2, [(1, 1)=a, (2, 2)=b]);

[Maple Math]

> mainDiagonal(B);

[Maple Math]

See Also:

Version History:

Version 1.0 - March 20, 1998