ahbarnett

% (Semi)analytic deriv of complex SVD wrt parameter-dep matrix.
% Barnett 5/2/25
clear
verb=0;

m=6; n=4;   % size
rng(0); % seed
for k=0:3, Ak{k+1} = randn(m,n)+1i*randn(m,n); end   % coeff mats
% generic random C-valued matrix poly, deg-3
Afun = @(z) Ak{1} + z*Ak{2} + z^2*Ak{3} + z^3*Ak{4};

ahbarnett

# FWAM25 demos on 1D func interpolation. all one big script.
# Used to generate figs for slides. Paste the bits you need.
# Barnett 10/13/25
using LinearAlgebra, CairoMakie, Chairmarks, Printf
using SpecialFunctions
using PolynomialRoots

fcostly(x) = sum((1.0/k)^x for k=1:1000000)     # expensive func
fcostly(2.0)
# [details for experts...