spmv#
Computes a matrix-vector product with a symmetric packed matrix.
Description
The spmv
routines compute a scalar-matrix-vector product and add the
result to a scalar-vector product, with a symmetric packed matrix.
The operation is defined as:
where:
alpha
and beta
are scalars,
A
is an n
-by-n
symmetric matrix, supplied in packed form,
x
and y
are vectors of length n
.
spmv
supports the following precisions.
T
float
double
spmv (Buffer Version)#
Syntax
namespace oneapi::mkl::blas::column_major {
void spmv(sycl::queue &queue,
onemkl::uplo upper_lower,
std::int64_t n,
T alpha,
sycl::buffer<T,1> &a,
sycl::buffer<T,1> &x,
std::int64_t incx,
T beta,
sycl::buffer<T,1> &y,
std::int64_t incy)
}
namespace oneapi::mkl::blas::row_major {
void spmv(sycl::queue &queue,
onemkl::uplo upper_lower,
std::int64_t n,
T alpha,
sycl::buffer<T,1> &a,
sycl::buffer<T,1> &x,
std::int64_t incx,
T beta,
sycl::buffer<T,1> &y,
std::int64_t incy)
}
Input Parameters
- queue
The queue where the routine should be executed.
- upper_lower
Specifies whether
A
is upper or lower triangular. See oneMKL Defined Datatypes for more details.- n
Number of rows and columns of
A
. Must be at least zero.- alpha
Scaling factor for the matrix-vector product.
- a
Buffer holding input matrix
A
. Must have size at least (n
*(n
+1))/2. See Matrix Storage for more details.- x
Buffer holding input vector
x
. The buffer must be of size at least (1 + (n
- 1)*abs(incx
)). See Matrix Storage for more details.- incx
Stride of vector
x
.- beta
Scaling factor for vector
y
.- y
Buffer holding input/output vector
y
. The buffer must be of size at least (1 + (n
- 1)*abs(incy
)). See Matrix Storage for more details.- incy
Stride of vector
y
.
Output Parameters
- y
Buffer holding the updated vector
y
.
spmv (USM Version)#
Syntax
namespace oneapi::mkl::blas::column_major {
sycl::event spmv(sycl::queue &queue,
onemkl::uplo upper_lower,
std::int64_t n,
T alpha,
const T *a,
const T *x,
std::int64_t incx,
T beta,
T *y,
std::int64_t incy,
const std::vector<sycl::event> &dependencies = {})
}
namespace oneapi::mkl::blas::row_major {
sycl::event spmv(sycl::queue &queue,
onemkl::uplo upper_lower,
std::int64_t n,
T alpha,
const T *a,
const T *x,
std::int64_t incx,
T beta,
T *y,
std::int64_t incy,
const std::vector<sycl::event> &dependencies = {})
}
Input Parameters
- queue
The queue where the routine should be executed.
- upper_lower
Specifies whether
A
is upper or lower triangular. See oneMKL Defined Datatypes for more details.- n
Number of rows and columns of
A
. Must be at least zero.- alpha
Scaling factor for the matrix-vector product.
- a
Pointer to input matrix
A
. The array holding input matrixA
must have size at least (n
*(n
+1))/2. See Matrix Storage for more details.- x
Pointer to input vector
x
. The array holding input vectorx
must be of size at least (1 + (n
- 1)*abs(incx
)). See Matrix Storage for more details.- incx
Stride of vector
x
.- beta
Scaling factor for vector
y
.- y
Pointer to input/output vector
y
. The array holding input/output vectory
must be of size at least (1 + (n
- 1)*abs(incy
)). See Matrix Storage for more details.- incy
Stride of vector
y
.- dependencies
List of events to wait for before starting computation, if any. If omitted, defaults to no dependencies.
Output Parameters
- y
Pointer to the updated vector
y
.
Return Values
Output event to wait on to ensure computation is complete.
Parent topic: BLAS Level 2 Routines