سوال ۲۶ کنکور ارشد علوم کامپیوتر ۱۴۰۰

Read the following excerpt from PASSAGE 1 ("Structure, Sparsity, and Black Boxes") and complete the sentence with the choice that best agrees with it.

A large matrix may have sparsity, i.e., relatively few nonzero entries. (The opposite of sparse is dense.) For example, a finite-difference equation may lead to a matrix with only a few nonzero entries per row. ... Some iterative algorithms also need no more than the ability to determine $Ax$ for any $x$. ... For example, given a sparse matrix $A$, it is easy to design an algorithm that is faster than $O(n^{2})$ operations. This is in marked contrast to the algorithms of classic linear algebra, such as Gaussian or Householder, which alter matrix entries so as to introduce zeros.

According to the passage:

An iterative approach, making use of ----------.