skcuda.cublas.cublasDdot

skcuda.cublas.cublasDdot(handle, n, x, incx, y, incy)[source]

Vector dot product (double precision real)

Computes the dot product of two double precision real vectors. cublasCdotc and cublasZdotc use the conjugate of the first vector when computing the dot product.

Parameters:
  • handle (int) – CUBLAS context.
  • n (int) – Number of elements in input vectors.
  • x (ctypes.c_void_p) – Pointer to double precision real input vector.
  • incx (int) – Storage spacing between elements of x.
  • y (ctypes.c_void_p) – Pointer to double precision real input/output vector.
  • incy (int) – Storage spacing between elements of y.
Returns:

d – Dot product of x and y.
Return type:

np.float64

Examples

>>> import pycuda.autoinit
>>> import pycuda.gpuarray as gpuarray
>>> import numpy as np
>>> x = np.float64(np.random.rand(5))
>>> y = np.float64(np.random.rand(5))
>>> x_gpu = gpuarray.to_gpu(x)
>>> y_gpu = gpuarray.to_gpu(y)
>>> h = cublasCreate()
>>> d = cublasDdot(h, x_gpu.size, x_gpu.gpudata, 1, y_gpu.gpudata, 1)
>>> cublasDestroy(h)
>>> np.allclose(d, np.dot(x, y))
True

Notes

Both x and y must contain n elements.

References

cublas<t>dot