spmv¶
Computes a matrix-vector product with a symmetric packed matrix.
Syntax
-
void
spmv
(queue &exec_queue, uplo upper_lower, std::int64_t n, T alpha, buffer<T, 1> &a, buffer<T, 1> &x, std::int64_t incx, T beta, buffer<T, 1> &y, std::int64_t incy)¶
spmv
supports the following precisions and devices.
T |
Devices Supported |
---|---|
|
Host, CPU, and GPU |
|
Host, CPU, and GPU |
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
y <- alpha*A*x + beta*y
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
.
Input Parameters
- exec_queue
The queue where the routine should be executed.
- upper_lower
Specifies whether
A
is upper or lower triangular. See Data Types 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 and Vector 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 and Vector 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 and Vector Storage for more details.- incy
Stride of vector
y
.
Output Parameters
- y
Buffer holding the updated vector
y
.