mars.tensor.amin#

mars.tensor.amin(a, axis=None, out=None, keepdims=None, combine_size=None)#

Return the minimum of a tensor or minimum along an axis.

Parameters

  • a (array_like) – Input data.

  • axis (None or int or tuple of ints, optional) –

    Axis or axes along which to operate. By default, flattened input is used.

    If this is a tuple of ints, the minimum is selected over multiple axes, instead of a single axis or all the axes as before.

  • out (Tensor, optional) – Alternative output tensor in which to place the result. Must be of the same shape and buffer length as the expected output. See doc.ufuncs (Section “Output arguments”) for more details.

  • 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 tensor.

    If the default value is passed, then keepdims will not be passed through to the amin method of sub-classes of Tensor, however any non-default value will be. If the sub-classes sum method does not implement keepdims any exceptions will be raised.

  • combine_size (int, optional) – The number of chunks to combine.

Returns

amin – Minimum of a. If axis is None, the result is a scalar value. If axis is given, the result is an array of dimension a.ndim - 1.

Return type

Tensor or scalar

See also

amax

The maximum value of a tensor along a given axis, propagating any NaNs.

nanmin

The minimum value of a tensor along a given axis, ignoring any NaNs.

minimum

Element-wise minimum of two tensors, propagating any NaNs.

fmin

Element-wise minimum of two tensors, ignoring any NaNs.

argmin

Return the indices of the minimum values.

nanmax, maximum, fmax

Notes

NaN values are propagated, that is if at least one item is NaN, the corresponding min value will be NaN as well. To ignore NaN values (MATLAB behavior), please use nanmin.

Don’t use amin for element-wise comparison of 2 tensors; when a.shape[0] is 2, minimum(a[0], a[1]) is faster than amin(a, axis=0).

Examples

>>> import mars.tensor as mt

>>> a = mt.arange(4).reshape((2,2))
>>> a.execute()
array([[0, 1],
       [2, 3]])
>>> mt.amin(a).execute()           # Minimum of the flattened array
0
>>> mt.amin(a, axis=0).execute()   # Minima along the first axis
array([0, 1])
>>> mt.amin(a, axis=1).execute()   # Minima along the second axis
array([0, 2])

>>> b = mt.arange(5, dtype=float)
>>> b[2] = mt.NaN
>>> mt.amin(b).execute()
nan
>>> mt.nanmin(b).execute()
0.0