Section 4: Problems
University-level exam questions for Computational Methods & Applications.
Norms and Conditioning
Problem 1.1
Compute ||A||₁, ||A||₂, and ||A||∞ for A = [[1, 2], [3, 4]].
Difficulty: Medium
Problem 1.2
Show that ||AB|| ≤ ||A|| ||B|| for any compatible matrix norm.
Difficulty: Medium
Problem 1.3
Compute the condition number κ₂(A) for A = [[1, 1], [1, 1+ε]] where ε is small.
Difficulty: Hard
Iterative Methods
Problem 2.1
Apply one iteration of Jacobi method to solve: 3x + y = 5 x + 2y = 5 starting from x₀ = [0, 0].
Difficulty: Easy
Problem 2.2
Prove that the Jacobi iteration for a strictly diagonally dominant matrix converges.
Difficulty: Very Hard
Eigenvalue Computation
Problem 3.1
Apply two iterations of the power method to A = [[2, 1], [1, 2]] starting with x₀ = [1, 0].
Difficulty: Medium
Problem 3.2
Explain why the power method fails for A = [[0, 1], [1, 0]].
Difficulty: Medium
Linear Programming
Problem 4.1
Solve using the simplex method: Maximize 3x + 4y Subject to: x + 2y ≤ 8, 3x + 2y ≤ 12, x,y ≥ 0
Difficulty: Hard
Problem 4.2
Write the dual of the LP in Problem 4.1 and verify strong duality.
Difficulty: Hard
Network Flow
Problem 5.1
Find the maximum flow in a network with given capacities.
Difficulty: Medium
Problem 5.2
Formulate the assignment problem as a linear program.
Difficulty: Medium
Game Theory
Problem 6.1
Find the optimal mixed strategies for the zero-sum game with payoff matrix: [[3, -1], [-2, 4]]
Difficulty: Hard
Problem 6.2
Formulate the game in Problem 6.1 as a linear program.
Difficulty: Very Hard
Challenge Problems
Problem 7.1
Prove the strong duality theorem for linear programming.
Difficulty: Very Hard
Problem 7.2
Implement the conjugate gradient method and analyze its convergence.
Difficulty: Very Hard
Solutions
Solutions are available in the implementation file with verification code.