Polynomial-to-Pade coefficient conversion

poly2pade converts polynomial coefficients to a Pade approximant's numerator and denominator coefficients.

[a,b] = poly2pade(c,N);

Given series coefficents c(1:M+N+1), find coefficients a(1:M+1) and b(1:N+1) to fit the rational approximation

(a(1)+a(2)*x+...+a(M+1)*x^M)/(b(1)+b(2)*x+...+b(N+1)*x^N) = c(1)+c(2)*x+...+c(M+N+1)*x^(M+N)+Ox^(M+N+1)

This replaces padecoef.m: https://www.mathworks.com/matlabcentral/fileexchange/114835-pade-coefficients The function name is changed to avoid conflict with https://www.mathworks.com/help/matlab/ref/padecoef.html Also, the implementation has been revised to use SVD to handle ill-conditioned problems.