nums.numpy.api.arithmetic module

nums.numpy.api.arithmetic.sum(a, axis=None, dtype=None, out=None, keepdims=False, initial=None, where=None)[source]

Sum of array elements over a given axis.

This docstring was copied from numpy.sum.

Some inconsistencies with the NumS version may exist.

Parameters

  • a (BlockArray) – Elements to sum.

  • axis (None or int or tuple of ints, optional) – Axis or axes along which a sum is performed. The default, axis=None, will sum all of the elements of the input array. If axis is negative it counts from the last to the first axis. If axis is a tuple of ints, a sum is performed on all of the axes specified in the tuple instead of a single axis or all the axes as before.

  • dtype (dtype, optional) – The type of the returned array and of the accumulator in which the elements are summed. The dtype of a is used by default unless a has an integer dtype of less precision than the default platform integer. In that case, if a is signed then the platform integer is used while if a is unsigned then an unsigned integer of the same precision as the platform integer is used.

  • out (BlockArray, optional) – Alternative output array in which to place the result. It must have the same shape as the expected output, but the type of the output values will be cast if necessary.

  • keepdims (bool, optional) – If this is set to True, the axes which are reduced are left in the result as dimensions with size one. With this option, the result will broadcast correctly against the input array. If the default value is passed, then keepdims will not be passed through to the sum method of sub-classes of BlockArray, however any non-default value will be. If the sub-class’ method does not implement keepdims any exceptions will be raised.

  • initial (scalar, optional) – Starting value for the sum.

  • where (BlockArray of bool, optional) – Elements to include in the sum.

Returns

sum_along_axis – An array with the same shape as a, with the specified axis removed. If a is a 0-d array, or if axis is None, a scalar is returned. If an output array is specified, a reference to out is returned.

Return type

BlockArray

See also

mean, average

Notes

‘initial’ is currently not supported.

‘where’ is currently not supported.

‘out’ is currently not supported.

Examples

The doctests shown below are copied from NumPy. They won’t show the correct result until you operate get().

>>> nps.sum(nps.array([0.5, 1.5])).get()  
array(2.)
>>> nps.sum(nps.array([[0, 1], [0, 5]])).get()  
array(6)
>>> nps.sum(nps.array([[0, 1], [0, 5]]), axis=0).get()  
array([0, 6])
>>> nps.sum(nps.array([[0, 1], [0, 5]]), axis=1).get()  
array([1, 5])