ON THE APPROXIMATE POLAR FACTORS
关于近似极因子

To compute the polar decomposition A=QH, usually an approximate unitaryfactor X of A is first computed, and then the matrix K-1/2(X~HA+A~HX) is takenas an approximate Hermitian factor of A. This paper introduces the residual R=A-XK, and gives an approximate analysis of the approximate polar factors K andX.