25.cuBLAS开发指南中文版--cuBLAS中的Level-2函数symv()

2.6.8. cublas<t>symv()

cublasStatus_t cublasSsymv(cublasHandle_t handle, cublasFillMode_t uplo,
                           int n, const float           *alpha,
                           const float           *A, int lda,
                           const float           *x, int incx, const float           *beta,
                           float           *y, int incy)
cublasStatus_t cublasDsymv(cublasHandle_t handle, cublasFillMode_t uplo,
                           int n, const double          *alpha,
                           const double          *A, int lda,
                           const double          *x, int incx, const double          *beta,
                           double          *y, int incy)
cublasStatus_t cublasCsymv(cublasHandle_t handle, cublasFillMode_t uplo,
                           int n, const cuComplex       *alpha, /* host or device pointer */
                           const cuComplex       *A, int lda,
                           const cuComplex       *x, int incx, const cuComplex       *beta,
                           cuComplex       *y, int incy)
cublasStatus_t cublasZsymv(cublasHandle_t handle, cublasFillMode_t uplo,
                           int n, const cuDoubleComplex *alpha,
                           const cuDoubleComplex *A, int lda,
                           const cuDoubleComplex *x, int incx, const cuDoubleComplex *beta,
                           cuDoubleComplex *y, int incy)

此函数执行对称矩阵向量乘法。

$y=\alpha Ax+\beta y$

其中 A 是以低模式或高模式存储的 n*n 对称矩阵，x 和y 是向量，而 $\alpha$ 和 $\beta$是标量。

这个函数有另一个更快的实现，它使用可以通过 cublasSetAtomicsMode() 启用的原子。

请参阅函数 cublasSetAtomicsMode() 部分了解有关原子使用的更多详细信息。

Param.	Memory	In/out	Meaning
handle		input	handle to the cuBLAS library context.
uplo		input	indicates if matrix A lower or upper part is stored, the other symmetric part is not referenced and is inferred from the stored elements.
n		input	number of rows and columns of matrix A.
alpha	host or device	input	<type> scalar used for multiplication.
A	device	input	<type> array of dimension lda x n with lda>=max(1,n).
lda		input	leading dimension of two-dimensional array used to store matrix A.
x	device	input	<type> vector with n elements.
incx		input	stride between consecutive elements of x.
beta	host or device	input	scalar used for multiplication, if beta==0 then y does not have to be a valid input.
y	device	input	<type> vector with n elements.
incy		input	stride between consecutive elements of y.

该函数可能返回的错误值及其含义如下所列。

ErrorValue	Meaning
CUBLAS_STATUS_SUCCESS	操作成功完成
CUBLAS_STATUS_NOT_INITIALIZED	库未初始化
CUBLAS_STATUS_INVALID_VALUE	参数 m,n<0 或 incx,incy=0
CUBLAS_STATUS_EXECUTION_FAILED	该功能无法在 GPU 上启动

请参考:
ssymv, dsymv