TRACE

Purpose:

Calculates the trace of an array, the sum of the diagonal elements.

TRACE(a)

Optional. An array or series, defaults to the current Window.

A real, the diagonal sum.

W1: {{1, 2, 3},

{4, 5, 6},

{7, 8, 9}}

trace(w1) returns 15.

TRACE defaults to the current series if no input is supplied.