Developer Reference

Contents

spr2

Computes a rank-2 update of a symmetric packed matrix.

Description

The
spr2
routines compute two scalar-vector-vector products and add them to a symmetric packed matrix. The operation is defined as:
LaTex Math image.
where:
  • alpha
    is scalar
  • A
    is
    n
    x
    n
    symmetric matrix, supplied in packed form
  • x
    and
    y
    are vectors of length
    n
spr2
supports the following precisions:
T
float
double

spr2 (Buffer Version)

Syntax
namespace oneapi::mkl::blas::column_major { void spr2(sycl::queue &queue, oneapi::mkl::uplo upper_lower, std::int64_t n, T alpha, sycl::buffer<T,1> &x, std::int64_t incx, sycl::buffer<T,1> &y, std::int64_t incy, sycl::buffer<T,1> &a) }
namespace oneapi::mkl::blas::row_major { void spr2(sycl::queue &queue, oneapi::mkl::uplo upper_lower, std::int64_t n, T alpha, sycl::buffer<T,1> &x, std::int64_t incx, sycl::buffer<T,1> &y, std::int64_t incy, sycl::buffer<T,1> &a) }
Input Parameters
queue
The queue where the routine should be executed.
upper_lower
Specifies whether matrix
A
is upper or lower triangular. See Data Types for more details.
n
Number of rows and columns of matrix
A
. Must be at least zero.
alpha
Scaling factor for the matrix-vector product.
x
Buffer holding input vector
x
. Size of the buffer must be at least (1 + (
n
- 1)*abs(
incx
)). See Matrix Storage for more details.
incx
Stride of vector
x
.
y
Buffer holding input/output vector
y
. Size of the buffer must be at least (1 + (
n
- 1)*abs(
incy
)). See Matrix Storage for more details.
incy
Stride of vector
y
.
a
Buffer holding input matrix
A
. Size of the buffer must be at least (
n
*(
n
-1))/2. See Matrix Storage for more details.
Output Parameters
a
Buffer holding updated upper triangular part of the symmetric matrix
A
if
upper_lower=upper
or updated lower triangular part of the symmetric matrix
A
if
upper_lower=lower
.

spr2 (USM Version)

Syntax
namespace oneapi::mkl::blas::column_major { sycl::event spr2(sycl::queue &queue, oneapi::mkl::uplo upper_lower, std::int64_t n, T alpha, const T *x, std::int64_t incx, const T *y, std::int64_t incy, T *a) }
namespace oneapi::mkl::blas::row_major { sycl::event spr2(sycl::queue &queue, oneapi::mkl::uplo upper_lower, std::int64_t n, T alpha, const T *x, std::int64_t incx, const T *y, std::int64_t incy, T *a) }
Input Parameters
queue
The queue where the routine should be executed.
upper_lower
Specifies whether matrix
A
is upper or lower triangular. See Data Types for more details.
n
Number of rows and columns of matrix
A
. Must be at least zero.
alpha
Scaling factor for the matrix-vector product.
x
Pointer to input vector
x
. Size of the array holding input vector
x
must be at least (1 + (
n
- 1)*abs(
incx
)). See Matrix Storage for more details.
incx
Stride of vector
x
.
y
Pointer to input/output vector
y
. Size of the array holding input/output vector
y
must be at least (1 + (
n
- 1)*abs(
incy
)). See Matrix Storage for more details.
incy
Stride of vector
y
.
a
Pointer to input matrix
A
. Size of the array holding input matrix
A
must be at least (
n
*(
n
-1))/2. See Matrix Storage for more details.
dependencies
List of events to wait for before starting computation, if any. If omitted, defaults to no dependencies.
Output Parameters
a
Pointer to updated upper triangular part of the symmetric matrix
A
if
upper_lower=upper
or updated lower triangular part of the symmetric matrix
A
if
upper_lower=lower
.
Return Values
Output event to wait on to ensure computation is complete.

Product and Performance Information

1

Performance varies by use, configuration and other factors. Learn more at www.Intel.com/PerformanceIndex.