U e{j#@s^dZddlZddlZddlmZddlmZddl m Z dgZ dd giZ Gd ddej ZdS) z` This module contains the classes and utility functions for distance and cartesian coordinates. N)units)AstropyWarning)AngleDistance*Zscipyc seZdZdZejZdZddddddej dddddf fdd Z e dd Z dd d Z e d d ZeddZe ddZZS)ra A one-dimensional distance. This can be initialized by providing one of the following: * Distance ``value`` (array or float) and a ``unit`` * |Quantity| object with dimensionality of length * Redshift and (optionally) a `~astropy.cosmology.Cosmology` * Distance modulus * Parallax Parameters ---------- value : scalar or `~astropy.units.Quantity` ['length'] The value of this distance. unit : `~astropy.units.UnitBase` ['length'] The unit for this distance. z : float A redshift for this distance. It will be converted to a distance by computing the luminosity distance for this redshift given the cosmology specified by ``cosmology``. Must be given as a keyword argument. cosmology : `~astropy.cosmology.Cosmology` or None A cosmology that will be used to compute the distance from ``z``. If `None`, the current cosmology will be used (see `astropy.cosmology` for details). distmod : float or `~astropy.units.Quantity` The distance modulus for this distance. Note that if ``unit`` is not provided, a guess will be made at the unit between AU, pc, kpc, and Mpc. parallax : `~astropy.units.Quantity` or `~astropy.coordinates.Angle` The parallax in angular units. dtype : `~numpy.dtype`, optional See `~astropy.units.Quantity`. copy : bool, optional See `~astropy.units.Quantity`. order : {'C', 'F', 'A'}, optional See `~astropy.units.Quantity`. subok : bool, optional See `~astropy.units.Quantity`. ndmin : int, optional See `~astropy.units.Quantity`. allow_negative : bool, optional Whether to allow negative distances (which are possible in some cosmologies). Default: `False`. Raises ------ `~astropy.units.UnitsError` If the ``unit`` is not a length unit. ValueError If value specified is less than 0 and ``allow_negative=False``. If ``cosmology`` is provided when ``z`` is *not* given. If either none or more than one of ``value``, ``z``, ``distmod``, or ``parallax`` were given. Examples -------- >>> from astropy import units as u >>> from astropy.cosmology import WMAP5 >>> Distance(10, u.Mpc) >>> Distance(40*u.pc, unit=u.kpc) >>> Distance(z=0.23) # doctest: +FLOAT_CMP >>> Distance(z=0.23, cosmology=WMAP5) # doctest: +FLOAT_CMP >>> Distance(distmod=24.47*u.mag) # doctest: +FLOAT_CMP >>> Distance(parallax=21.34*u.mas) # doctest: +FLOAT_CMP TNFrc  stdd||||fD} | dkr,tdn| dkrvsz#Distance.__new__..rzQnone of `value`, `z`, `distmod`, or `parallax` were given to Distance constructorrzZmore than one of `value`, `z`, `distmod`, or `parallax` were given to Distance constructorFdefault_cosmologyzHa `cosmology` was given but `z` was not provided in Distance constructor)Z equivalenciesznegative parallaxes are converted to NaN distances even when `allow_negative=True`, because negative parallaxes cannot be transformed into distances. See the discussion in this paper: https://arxiv.org/abs/1507.02105zsome parallaxes are negative, which are not interpretable as distances. See the discussion in this paper: https://arxiv.org/abs/1507.02105 . You can convert negative parallaxes to NaN distances by providing the `allow_negative=True` argument.)dtypecopyordersubokndminzWdistance must be >= 0. Use the argument `allow_negative=True` to allow negative values.)sum ValueErrorastropy.cosmologyrgetluminosity_distance_distmod_to_pcnplog10valueZmeanuZMpcZkpcZAUpcto_valueparallaxanywarningswarnrsuper__new__)clsrunitz cosmologydistmodr#rrrrrZallow_negativeZ n_not_nonerZ meanlogvalZdistance __class__rr r(gsv       zDistance.__new__cCs|S)zShort for ``self.compute_z()``) compute_zselfrrr r+sz Distance.zcKsDddlm}|dkr(ddlm}|}|dd||j|f|S)a The redshift for this distance assuming its physical distance is a luminosity distance. Parameters ---------- cosmology : `~astropy.cosmology.Cosmology` or None The cosmology to assume for this calculation, or `None` to use the current cosmology (see `astropy.cosmology` for details). **atzkw keyword arguments for :func:`~astropy.cosmology.z_at_value` Returns ------- z : `~astropy.units.Quantity` The redshift of this distance given the provided ``cosmology``. Warnings -------- This method can be slow for large arrays. The redshift is determined using :func:`astropy.cosmology.z_at_value`, which handles vector inputs (e.g. an array of distances) by element-wise calling of :func:`scipy.optimize.minimize_scalar`. For faster results consider using an interpolation table; :func:`astropy.cosmology.z_at_value` provides details. See Also -------- :func:`astropy.cosmology.z_at_value` : Find the redshift corresponding to a :meth:`astropy.cosmology.FLRW.luminosity_distance`. r) z_at_valueNr Zztolg|=)rr3rr setdefaultr)r2r,Zatzkwr3rrrr r0s   zDistance.compute_zcCs,dt|tjd}tj|tjddS)z3The distance modulus as a `~astropy.units.Quantity`@Fr)rrr"r r!Quantitymag)r2valrrr r-szDistance.distmodcCs,t|tj}|d|jddtjddS)N r5Fr6)r r7r8rr!)r)dmrrr rszDistance._distmod_to_pccCst|tjtS)zs