Developer Reference for Intel® oneAPI Math Kernel Library for Fortran
?lapll
Measures the linear dependence of two vectors.
Syntax
call slapll ( n , x , incx , Y , incy , ssmin )
call dlapll ( n , x , incx , Y , incy , ssmin )
call clapll ( n , x , incx , Y , incy , ssmin )
call zlapll ( n , x , incx , Y , incy , ssmin )
Include Files
mkl.fi
Description
slapll dlapll clapll zlapll
Given two column vectors x and y of length n , let
A = (xy) be the n -by-2 matrix.
The routine ?lapll first computes the QR factorization of A as 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 .
Input Parameters
- n
-
INTEGER . The length of the vectors x and y .
- x
-
REAL for slapll DOUBLE PRECISION for dlapll COMPLEX for clapll DOUBLE COMPLEX for zlapll Array, DIMENSION (1+(n-1)incx) . On entry, x contains the n -vector x.
- y
-
REAL for slapll DOUBLE PRECISION for dlapll COMPLEX for clapll DOUBLE COMPLEX for zlapll Array, DIMENSION (1+( n -1) incy ). On entry, y contains the n -vector y.
- incx
-
INTEGER . The increment between successive elements of x; incx > 0 .
- incy
-
INTEGER . The increment between successive elements of y; incy > 0 .
Output Parameters
- x
-
On exit, x is overwritten.
- y
-
On exit, y is overwritten.
- ssmin
-
REAL for slapll / clapll DOUBLE PRECISION for dlapll / zlapll The smallest singular value of the n -by-2 matrix A = ( xy ).