Source code for mars.tensor.arithmetic.arcsin

#!/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 TensorArcsin(TensorUnaryOp):
    _op_type_ = OperandDef.ARCSIN
    _func_name = 'arcsin'


[docs]@infer_dtype(np.arcsin) def arcsin(x, out=None, where=None, **kwargs): """ Inverse sine, element-wise. Parameters ---------- x : array_like `y`-coordinate on the unit circle. 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 ------- angle : Tensor The inverse sine of each element in `x`, in radians and in the closed interval ``[-pi/2, pi/2]``. If `x` is a scalar, a scalar is returned, otherwise a tensor. See Also -------- sin, cos, arccos, tan, arctan, arctan2, emath.arcsin Notes ----- `arcsin` is a multivalued function: for each `x` there are infinitely many numbers `z` such that :math:`sin(z) = x`. The convention is to return the angle `z` whose real part lies in [-pi/2, pi/2]. For real-valued input data types, *arcsin* 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, `arcsin` is a complex analytic function that has, by convention, the branch cuts [-inf, -1] and [1, inf] and is continuous from above on the former and from below on the latter. The inverse sine is also known as `asin` or sin^{-1}. References ---------- Abramowitz, M. and Stegun, I. A., *Handbook of Mathematical Functions*, 10th printing, New York: Dover, 1964, pp. 79ff. http://www.math.sfu.ca/~cbm/aands/ Examples -------- >>> import mars.tensor as mt >>> mt.arcsin(1).execute() # pi/2 1.5707963267948966 >>> mt.arcsin(-1).execute() # -pi/2 -1.5707963267948966 >>> mt.arcsin(0).execute() 0.0 """ op = TensorArcsin(**kwargs) return op(x, out=out, where=where)