Questions tagged [complex-analysis]

For questions involving analysis of complex functions (e.g. calculus with complex variables, residues, holomorphism). Should focus on particularities of evaluating complex functions/equations. For general questions about arithmetic on complex numbers, use the [complex-arithmetic] tag.

25 questions
15
votes
1 answer

How to numerically calculate residues?

I need to calculate the following integral: $$ {1\over 2\pi i} \int_C f(E) \, d E $$ $$ f(E) = {\rm Tr}\,\left(({\bf h} + E)\,{\bf G}(E) \right) $$ Where $\bf h$ is a matrix (one particle kinetic and potential energy expressed in a basis), $\bf G$…
Ondřej Čertík
  • 2,930
  • 18
  • 40
1
vote
0 answers

Plot FDE Amplification Factor in Complex Plane

I am reviewing stability of finite difference methods. I am using the von Neumann method to study a linear PDE and an explicit finite difference scheme. The goal is to develop an expression for an amplification factor $G$. I've read that if $G$ is a…
Nukesub
  • 163
  • 4
0
votes
1 answer

Calculating residue of a rational function

I have a function $$ f(z) = \frac{1}{(z-z_1)(z-z_2)(z-z_3)(z-z_4)} $$ All of $\{z_1,z_2,z_3,z_4\}$ are simple poles. The residues for this function are given as $$ \text{Res}(f(z),z_i)= \lim\limits_{z\to zi}…
Galilean
  • 151
  • 6