MATH 645 UNH Vectors Dot Products & Schwarz Inequality Exercises Exam Practice
I need an explanation for this Algebra question to help me study.
10 problems A band matrix is a square matrix with nonzero entries only on the main diagonal and
on w of the diagonals above and below the main diagonal, and zeros everywhere else. The matrix B
below is an example of a 5×5 symmetric band matrix with w = 1. Elimination for band matrices is
much cheaper than elimination for ordinary matrices. For a generic n × n band matrix B with exactly
w nonzero bands above and below the main diagonal, approximately how many multiplication and
subtraction operations are necessary for elimination B → U?
1 2 0 0 0
2 1 2 0 0
B=
0 2 1 2 0
0 0 2 1 2
0 0 0 2 1