mars.tensor.arccos¶

mars.tensor.
arccos
(x, out=None, where=None, **kwargs)[source]¶ Trigonometric inverse cosine, elementwise.
The inverse of cos so that, if
y = cos(x)
, thenx = arccos(y)
. x : array_like
 xcoordinate on the unit circle. For real arguments, the domain is [1, 1].
 out : Tensor, None, or tuple of Tensor and None, optional
 A location into which the result is stored. If provided, it must have a shape that the inputs broadcast to. If not provided or None, a freshlyallocated tensor is returned. A tuple (possible only as a keyword argument) must have length equal to the number of outputs.
 where : array_like, optional
 Values of True indicate to calculate the ufunc at that position, values of False indicate to leave the value in the output alone.
**kwargs
 angle : Tensor
 The angle of the ray intersecting the unit circle at the given xcoordinate in radians [0, pi]. If x is a scalar then a scalar is returned, otherwise an array of the same shape as x is returned.
cos, arctan, arcsin
arccos is a multivalued function: for each x there are infinitely many numbers z such that cos(z) = x. The convention is to return the angle z whose real part lies in [0, pi].
For realvalued input data types, arccos always returns real output. For each value that cannot be expressed as a real number or infinity, it yields
nan
and sets the invalid floating point error flag.For complexvalued input, arccos is a complex analytic function that has branch cuts [inf, 1] and [1, inf] and is continuous from above on the former and from below on the latter.
The inverse cos is also known as acos or cos^1.
M. Abramowitz and I.A. Stegun, “Handbook of Mathematical Functions”, 10th printing, 1964, pp. 79. http://www.math.sfu.ca/~cbm/aands/
We expect the arccos of 1 to be 0, and of 1 to be pi: >>> import mars.tensor as mt
>>> mt.arccos([1, 1]).execute() array([ 0. , 3.14159265])
Plot arccos:
>>> import matplotlib.pyplot as plt >>> x = mt.linspace(1, 1, num=100) >>> plt.plot(x.execute(), mt.arccos(x).execute()) >>> plt.axis('tight') >>> plt.show()