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LAPACK
3.7.0
LAPACK: Linear Algebra PACKage
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subroutine slapll | ( | integer | N, |
real, dimension( * ) | X, | ||
integer | INCX, | ||
real, dimension( * ) | Y, | ||
integer | INCY, | ||
real | SSMIN | ||
) |
SLAPLL measures the linear dependence of two vectors.
Download SLAPLL + dependencies [TGZ] [ZIP] [TXT]
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.
[in] | N | N is INTEGER The length of the vectors X and Y. |
[in,out] | X | X is REAL array, dimension (1+(N-1)*INCX) On entry, X contains the N-vector X. On exit, X is overwritten. |
[in] | INCX | INCX is INTEGER The increment between successive elements of X. INCX > 0. |
[in,out] | Y | Y is REAL array, dimension (1+(N-1)*INCY) On entry, Y contains the N-vector Y. On exit, Y is overwritten. |
[in] | INCY | INCY is INTEGER The increment between successive elements of Y. INCY > 0. |
[out] | SSMIN | SSMIN is REAL The smallest singular value of the N-by-2 matrix A = ( X Y ). |
Definition at line 104 of file slapll.f.