Source code for mars.tensor.arithmetic.arctanh

#!/usr/bin/env python
# -*- coding: utf-8 -*-
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import numpy as np

from ... import opcodes as OperandDef
from ..utils import infer_dtype
from .core import TensorUnaryOp
from .utils import arithmetic_operand


@arithmetic_operand(sparse_mode='unary')
class TensorArctanh(TensorUnaryOp):
    _op_type_ = OperandDef.ARCTANH
    _func_name = 'arctanh'


[docs]@infer_dtype(np.arctanh) def arctanh(x, out=None, where=None, **kwargs): """ Inverse hyperbolic tangent element-wise. Parameters ---------- x : array_like Input tensor. 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 freshly-allocated 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 Returns ------- out : Tensor Array of the same shape as `x`. Notes ----- `arctanh` is a multivalued function: for each `x` there are infinitely many numbers `z` such that `tanh(z) = x`. The convention is to return the `z` whose imaginary part lies in `[-pi/2, pi/2]`. For real-valued input data types, `arctanh` 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 complex-valued input, `arctanh` is a complex analytical function that has branch cuts `[-1, -inf]` and `[1, inf]` and is continuous from above on the former and from below on the latter. The inverse hyperbolic tangent is also known as `atanh` or ``tanh^-1``. References ---------- .. [1] M. Abramowitz and I.A. Stegun, "Handbook of Mathematical Functions", 10th printing, 1964, pp. 86. http://www.math.sfu.ca/~cbm/aands/ .. [2] Wikipedia, "Inverse hyperbolic function", http://en.wikipedia.org/wiki/Arctanh Examples -------- >>> import mars.tensor as mt >>> mt.arctanh([0, -0.5]).execute() array([ 0. , -0.54930614]) """ op = TensorArctanh(**kwargs) return op(x, out=out, where=where)