Developer Reference

  • 2020.2
  • 07/15/2020
  • Public Content
Contents

?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
Given two column vectors
x
and
y
of length
n
, let
A
= (
x
y
)
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
= (
x
y
).

Product and Performance Information

1

Intel's compilers may or may not optimize to the same degree for non-Intel microprocessors for optimizations that are not unique to Intel microprocessors. These optimizations include SSE2, SSE3, and SSSE3 instruction sets and other optimizations. Intel does not guarantee the availability, functionality, or effectiveness of any optimization on microprocessors not manufactured by Intel. Microprocessor-dependent optimizations in this product are intended for use with Intel microprocessors. Certain optimizations not specific to Intel microarchitecture are reserved for Intel microprocessors. Please refer to the applicable product User and Reference Guides for more information regarding the specific instruction sets covered by this notice.

Notice revision #20110804