clapll-f(3)

clapll.f –

Synopsis

Functions/Subroutines

subroutine clapll (N, X, INCX, Y, INCY, SSMIN)
CLAPLL measures the linear dependence of two vectors.

Function/Subroutine Documentation

subroutine clapll (integerN, complex, dimension( * )X, integerINCX, complex, dimension( * )Y, integerINCY, realSSMIN)

CLAPLL 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.

Parameters:

 N is INTEGER
 The length of the vectors X and Y.

 X is COMPLEX 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 is COMPLEX 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 REAL
 The smallest singular value of the N-by-2 matrix A = ( X Y ).

Author:

Univ. of Tennessee

Univ. of California Berkeley

Univ. of Colorado Denver

NAG Ltd.

Date:

September 2012

Definition at line 101 of file clapll.f.

Author

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