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# numpy.cumprod

numpy.cumprod(a, axis=None, dtype=None, out=None)

  Return the cumulative product of elements along a given axis.

  Parameters:
    a array_like

      Input array.

    axis int, optional

      Axis along which the cumulative product is computed. By default the input is flattened.

    dtype dtype, optional

      Type of the returned array, as well as of the accumulator in which the elements are multiplied. If dtype is not specified, it defaults to the dtype of a, unless a has an integer dtype with a precision less than that of the default platform integer. In that case, the default platform integer is used instead.

    out ndarray, optional

      Alternative output array in which to place the result. It must have the same shape and buffer length as the expected output but the type of the resulting values will be cast if necessary.

  Returns:
    cumprod ndarray

      A new array holding the result is returned unless out is specified, in which case a reference to out is returned.

  See also

  `cumulative_prod`

    Array API compatible alternative for `cumprod`.

  Output type determination

  Notes

  Arithmetic is modular when using integer types, and no error is raised on overflow.

  Examples

      >>> import numpy as np
      >>> a = np.array([1,2,3])
      >>> np.cumprod(a) # intermediate results 1, 1*2
      ...               # total product 1*2*3 = 6
      array([1, 2, 6])
      >>> a = np.array([[1, 2, 3], [4, 5, 6]])
      >>> np.cumprod(a, dtype=np.float64)  # specify type of output
      array([   1.,    2.,    6.,   24.,  120.,  720.])

  The cumulative product for each column (i.e., over the rows) of a:

      >>> np.cumprod(a, axis=0)
      array([[ 1,  2,  3],
             [ 4, 10, 18]])

  The cumulative product for each row (i.e. over the columns) of a:

      >>> np.cumprod(a,axis=1)
      array([[  1,   2,   6],
             [  4,  20, 120]])