subroutine zlapll (N, X, INCX, Y, INCY, SSMIN)
subroutine zlapll (integerN, complex*16, dimension( * )X, integerINCX, complex*16, dimension( * )Y, integerINCY, double precisionSSMIN)ZLAPLL measures the linear dependence of two vectors. Purpose:
Given two column vectors X and Y, let A = ( X Y ). The subroutine first computes the QR factorization of A = Q*R, and then computes the SVD of the 2-by-2 upper triangular matrix R. The smaller singular value of R is returned in SSMIN, which is used as the measurement of the linear dependency of the vectors X and Y.
N is INTEGER The length of the vectors X and Y.X
X is COMPLEX*16 array, dimension (1+(N-1)*INCX) On entry, X contains the N-vector X. On exit, X is overwritten.INCX
INCX is INTEGER The increment between successive elements of X. INCX > 0.Y
Y is COMPLEX*16 array, dimension (1+(N-1)*INCY) On entry, Y contains the N-vector Y. On exit, Y is overwritten.INCY
INCY is INTEGER The increment between successive elements of Y. INCY > 0.SSMIN
SSMIN is DOUBLE PRECISION The smallest singular value of the N-by-2 matrix A = ( X Y ).
Univ. of Tennessee Univ. of California Berkeley Univ. of Colorado Denver NAG Ltd.Date:
September 2012Definition at line 101 of file zlapll.f.