This book provides the mathematical basis for investigating numerically equations from physics, life sciences or engineering. Tools for analysis and algorithms are confronted to a large set of relevant examples that show the difficulties and the limitations of the most naïve approaches. These examples not only provide the opportunity to put into practice mathematical statements, but modeling issues are also addressed in detail, through the mathematical perspective.
Preface ix
Chapter 1. Ordinary Differential Equations 1
1.1. Introduction to the theory of ordinary differential equations 1
1.1.1. Existence–uniqueness of first-order ordinary differential equations 1
1.1.2. The concept of maximal solution 11
1.1.3. Linear systems with constant coefficients 16
1.1.4. Higher-order differential equations 20
1.1.5. Inverse function theorem and implicit function theorem 21
1.2. Numerical simulation of ordinary differential equations, Euler schemes, notions of convergence, consistence and stability 27
1.2.1. Introduction 27
1.2.2. Fundamental notions for the analysis of numerical ODE methods 29
1.2.3. Analysis of explicit and implicit Euler schemes 33
1.2.4. Higher-order schemes 50
1.2.5. Leslie’s equation (Perron–Frobenius theorem, power method) 51
1.2.6. Modeling red blood cell agglomeration 78
1.2.7. SEI model 87
1.2.8. A chemotaxis problem 93
1.3. Hamiltonian problems 102
1.3.1. The pendulum problem 106
1.3.2. Symplectic matrices; sympllsè