Andrzej Kielbasinski, Krystyna Zietak, " Numerical behaviour of Higham's
scaled method for polar decomposition"

We present a rounding error analysis of Higham's scaled method
for computing the polar decomposition of a nonsingular complex
matrix. Under certain natural conditions we prove that the method
computes acceptable polar factors.

keywords: roundoff error analysis, polar decomposition of a matrix, 
Higham's method