cblas_?syr2
cblas_?syr2
Performs
a rank-2 update of a symmetric matrix.Syntax
void
cblas_ssyr2
(
const
CBLAS_LAYOUT
Layout
,
const
CBLAS_UPLO
uplo
,
const
MKL_INT
n
,
const
float
alpha
,
const
float
*x
,
const
MKL_INT
incx
,
const
float
*y
,
const
MKL_INT
incy
,
float
*a
,
const
MKL_INT
lda
);
void
cblas_dsyr2
(
const
CBLAS_LAYOUT
Layout
,
const
CBLAS_UPLO
uplo
,
const
MKL_INT
n
,
const
double
alpha
,
const
double
*x
,
const
MKL_INT
incx
,
const
double
*y
,
const
MKL_INT
incy
,
double
*a
,
const
MKL_INT
lda
);
Include Files
- mkl.h
Description
The
?syr2
routines perform a matrix-vector operation defined as A := alpha*x*y'+ alpha*y*x' + A,
where:
alpha
is scalar,x
and y
are n
-element vectors,A
is an n
-by-n
symmetric matrix.Input Parameters
- Layout
- Specifies whether two-dimensional array storage is row-major (CblasRowMajor) or column-major (CblasColMajor).
- uplo
- Specifies whether the upper or lower triangular part of the arrayais used.If, then the upper triangular part of the arrayuplo=CblasUpperais used.If, then the low triangular part of the arrayuplo=CblasLowerais used.
- n
- Specifies the order of the matrixA. The value ofnmust be at least zero.
- alpha
- Specifies the scalaralpha.
- x
- Array, size at least(1 + (. Before entry, the incremented arrayn- 1)*abs(incx))xmust contain then-element vectorx.
- incx
- Specifies the increment for the elements ofx.The value ofincxmust not be zero.
- y
- Array, size at least(1 + (. Before entry, the incremented arrayn- 1)*abs(incy))ymust contain then-element vectory.
- incy
- Specifies the increment for the elements ofy. The value ofincymust not be zero.
- a
- Array, size.lda*nBefore entry with, the leadinguplo=CblasUppern-by-nupper triangular part of the arrayamust contain the upper triangular part of the symmetric matrix and the strictly lower triangular part ofais not referenced.Before entry with, the leadinguplo=CblasLowern-by-nlower triangular part of the arrayamust contain the lower triangular part of the symmetric matrix and the strictly upper triangular part ofais not referenced.
- lda
- Specifies the leading dimension ofaas declared in the calling (sub)program. The value ofldamust be at leastmax(1,.n)
Output Parameters
- a
- With, the upper triangular part of the arrayuplo=CblasUpperais overwritten by the upper triangular part of the updated matrix.With, the lower triangular part of the arrayuplo=CblasLowerais overwritten by the lower triangular part of the updated matrix.