36.cuBLAS开发指南中文版--cuBLAS中的Level-2函数hpmv()

2.6.19. cublashpmv()

cublasStatus_t cublasChpmv(cublasHandle_t handle, cublasFillMode_t uplo,
                           int n, const cuComplex       *alpha,
                           const cuComplex       *AP,
                           const cuComplex       *x, int incx,
                           const cuComplex       *beta,
                           cuComplex       *y, int incy)
cublasStatus_t cublasZhpmv(cublasHandle_t handle, cublasFillMode_t uplo,
                           int n, const cuDoubleComplex *alpha,
                           const cuDoubleComplex *AP,
                           const cuDoubleComplex *x, int incx,
                           const cuDoubleComplex *beta,
                           cuDoubleComplex *y, int incy)

$y=\alpha Ax+\beta y$

其中 A 是以压缩格式存储的 nxn Hermitian 矩阵，x 和 y 是向量，α 和 β 是标量。

如果 uplo == CUBLAS_FILL_MODE_LOWER 那么Hermitian矩阵 A 的下三角部分的元素被逐列无间隙地打包在一起，使得元素 A(i,j) 存储在内存位置 AP[i+((2* n-j+1)*j)/2] 对于 j=1,…,n 和 i>=j。 因此，打包格式只需要 n(n+1)/2 个元素进行存储。

如果 uplo == CUBLAS_FILL_MODE_UPPER 则将厄米矩阵 A 的上三角部分的元素逐列无间隙地打包在一起，使得元素 A(i,j) 存储在内存位置 AP[i+(j*( j+1))/2] 对于 j=1,…,n 和 i<=j 。 因此，打包格式只需要 n(n+1)/2 个元素进行存储。

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 Hermitian part is not referenced and is inferred from the stored elements.
n		input	number of columns of matrix A.
alpha	host or device	input	scalar used for multiplication.
AP	device	input	array with A stored in packed format. The imaginary parts of the diagonal elements are assumed to be zero.
x	device	input	vector with n elements if transa == CUBLAS_OP_N and m elements otherwise.
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	in/out	vector at least (1+(m-1)*abs(incy)) elements if transa==CUBLAS_OP_N and at least (1+(n-1)*abs(incy)) elements otherwise.
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	If n < 0 or k < 0 or if incx = 0 or incy = 0 or if uplo != CUBLAS_FILL_MODE_LOWER, CUBLAS_FILL_MODE_UPPER or if lda < (k + 1) or alpha == NULL or beta == NULL
CUBLAS_STATUS_EXECUTION_FAILED	该功能无法在 GPU 上启动

详细信息, 请参考:

chpmv, zhpmv