Question

A banded matrix is defined as ____________

(a) Non zero elements are contained in band

(b) Zero elements are contained in a band

(c) Non zero elements are contained out of a band

(d) Both Non zero elements and Zero elements

I had been asked this question in an online interview.

My question comes from Gaussian Elimination in portion Matrix Algebra and Gaussian Elimination of Finite Element Method

Answer 1

The correct answer is (a) Non zero elements are contained in band

To explain I would say: A band matrix is a sparse matrix whose non zero entries are confined to a diagonal band. In a banded matrix, all of the non zero elements are contained within a band; outside of the band all elements are zero.