skcuda.cublas.cublasDasum

skcuda.cublas.cublasDasum(handle, n, x, incx)[source]

Sum of absolute values of double precision real vector.

Computes the sum of the absolute values of the elements of a double precision real vector.

Note: if the vector is complex, then this computes the sum sum(abs(x.real)) + sum(abs(x.imag))

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

Examples

>>> import pycuda.autoinit
>>> import pycuda.gpuarray as gpuarray
>>> import numpy as np
>>> x = np.random.rand(5).astype(np.float64)
>>> x_gpu = gpuarray.to_gpu(x)
>>> h = cublasCreate()
>>> s = cublasDasum(h, x_gpu.size, x_gpu.gpudata, 1)
>>> cublasDestroy(h)
>>> np.allclose(s, abs(x.real).sum() + abs(x.imag).sum())
True
Returns:s – Sum of absolute values.
Return type:numpy.float64

References

cublas<t>sum