Galpy

==================

- Added support for providing inputs to all initializations, methods,
and functions as Quantities with units and for providing outputs as
astropy Quantities. See pull request 258 and the documentation for
full details.

- Added TwoPowerTriaxialPotential, a set of triaxial potentials with
iso-density contours that are arbitrary, similar, coaxial ellipsoids
whose 'radial' density is a (different) power-law at small and large
radii: 1/m^alpha/(1+m)^beta-alpha (the triaxial generalization of
TwoPowerSphericalPotential, with flattening in the density rather
than in the potential, see Merritt & Fridman 1996, Binney & Tremaine
2008). These include triaxial Hernquist and NFW potentials. Includes
fast C implementations that allow efficient orbit integration in
these potentials (<~5 ms / orbit).

- Added SCFPotential, a class that implements general
density/potential pairs through the basis expansion approach to
solving the Poisson equation of Hernquist & Ostriker (1992). Also
implemented functions to compute the coefficients for a given
density function.

- Implemented galpy.actionAngle.actionAngleIsochroneApprox (Bovy 2014)
for the general case of a time-independent potential, allowing
action-angle coordinates to be computed for triaxial
potentials. Previously, this module only supported axisymmetric
potentials. Also allow the maximum number of terms in the expansion
to be set object-wide and allow a fixed time-step to be used in the
necessary orbit integration.

- Added an (experimental) interface to Binney & McMillan's TorusMapper
code for computing positions and velocities for given actions and
angles. See the installation instructions for how to properly
install this.

- Re-defined the amplitude parameters of a few potentials to allow for
easier setups with amplitudes provided as Quantities with
units. This is the case for FlattenedPowerPotential,
PowerSphericalPotential, and PowerSphericalPotentialwCutoff,
CosmphiDiskPotential, LopsidedDiskPotential, and
EllipticalDiskPotential.

- Added a module for modeling the effect of a subhalo impact on a
tidal stream (galpy.df.streamgapdf); see Sanders, Bovy, & Erkal
(2016). Also includes the fast methods for computing the density
along the stream and the stream track for a perturbed stream from
Bovy, Erkal, & Sanders (2016).

- Added functions to galpy.df.streamdf to compute the length of the
stream, the density along the stream quickly (in various
coordinates, including custom sky coordinates), to compute the
probability p(freq_parallel,angle_parallel), and to estimate the
number of encounters with DM subhalos. Also allow the stream track
to be computing using the new actionAngleTorus (this last addition
is still very experimental).

- Added PseudoIsothermalPotential, a standard pseudo-isothermal-sphere
potential.

- Added KuzminDiskPotential, a potential represented by a razor thin
disk

- Allow transformations to custom sets of sky coordinates in
galpy.util.bovy_coords.

- Added the spherical radius as an Orbit method.

- Added the spherical-radial force as a Potential method (rforce) and
function (evaluaterforces).

- Support for flipping the velocities of an orbit in-place (useful for
backwards integration).

- quasiisothermaldf input ro replaced by refr to avoid clash with ro
that specifies units (see above).

- Properly intercept CTRL-C (SIGINT) signals during orbit integration
in C, allowing long orbit integrations to be interrupted without
killing an entire Python session.

- Internally use astropy.coordinates transformations to transform
between (ra,dec) and (l,b). Can be tuned using the astropy-coords
configuration parameter. Also allow general epochs for the (ra,dec)
specification.

==================

- Added Python 3 support: in particular, Python 3.3 and 3.4 are now
supported; earlier 3.* may also work, but haven't been
tested. Python 2 and 3 are supported using a single common codebase.

- Added SnapshotRZPotential and InterpSnapshotRZPotential potential
classes: these can be used to get a frozen snapshot of the potential
of an N-body simulation into galpy. SnapshotRZPotential directly
calculates the potential and forces using direct summation;
InterpSnapshotRZPotential builds an interpolation table (it's a
subclass of interpRZPotential and can be used in the same way). This
code was mainly written by Rok Roskar.

- Added KuzminKutuzovStaeckelPotential, a Staeckel potential that can
be used to approximate the potential of a disk galaxy (see Batsleer
& Dejonghe 1994).

- Added MN3ExponentialDiskPotential that gives the approximation to a
radially-exponential disk potential as three Miyamoto-Nagai disks
from Smith et al. (2015; arXiv:1502.00627v1)

- Added PlummerPotential, a standard Plummer potential.

- Add support for converting potential parameters to NEMO format and
units: nemo_accname and nemo_accpars (both instance and general
Potential method).

- Added nemo/ directory for C++ implementations of additional NEMO
potentials (not included in the NEMO release); add PowSphwCut.cc for
PowerSphericalPotential2Cutoff and Makefile to compile and install
it. This allows gyrfalcON simulations with MWPotential2014.

- Allow user to directly specify the integration step size to use in
orbit integration.

- Better implementations of vcirc, eipfreq, and verticalfreq for lists
of potentials that allows for negative amplitude components.

- Improvements to streamdf: add progIsTrack keyword to specify that
the progenitor= keyword actually specifies the desired starting
phase-space point of the track; the phase-space point of the
progenitor is calculated. Refactored streamdf setup to make this
easy to implement.

- Orbit fitting can now be performed in custom sky coordinates
(requires one to specify customsky=True and to implement and pass
the functions (a) lb_to_customsky= and (b) pmllpmbb_to_customsky=,
similar to lb_to_radec and pmllpmbb_to_pmradec). For example, this
allows one to do an orbit fit in the GD-1 frame of Koposov et
al. (2010).

- Orbit.time now returns the times at which an Orbit is integrated if
called without arguments.

- Slightly improved implementation of actionAngleStaeckel.py (more
robust umin/umax finding).

==================

- Added MWPotential2014: a Milky-Way-like potential fit to a bunch of
relevant data on the Milky Way; supersedes MWPotential, which is
still included; changed many examples to use this new potential;

- Changed default integrator to symplec4_c;

- Changed default vo and ro to 220 km/s and 8 kpc, respectively;

- Allow Orbit initialization to specify a distance and velocity scale
that is then used to output distances, velocities, energies,
actions, etc. in physical coordinates;

- Added an orbit-fitting routine (Orbit.fit).

- Added virial radius of NFW potential, allow initialization of NFW
potential with concentration and mass;

- Added potential.mass to return the mass enclosed for individual
potential instances; both spherical and axisymmetric potentials are
covered.

- Sped up many of the functions in galpy.util.bovy_coords by removing
scipy.frompyfunc dependency;

- Added galpy.util.bovy_conversion.dens_in_gevcc,
galpy.util.bovy_conversion.force_in_10m13kms2,
galpy.util.bovy_conversion.dens_in_criticaldens,
galpy.util.bovy_conversion.dens_in_meanmatterdens.

- Much improved test coverage.

- Added planarPotential.LinShuReductionFactor to calculate the
reduction factor for the response of a kinematically warm population
to a spiral perturbation.

- Added non-axisymmetric DFs to the top-level and the documentation.

- New streamdf track calculation (see arXiv_v2/published version of
Bovy 2014); better handdling of coordinate-transformation
parameters in streamdf.

- Installation now prints informative message about whether or not the
C extensions were installed.

- More informative warning messages when C functions are not used.

- Fix issues with non-square grids in the C implementation of
interpRZPotential.

- Added Orbit.flip to generate new Orbit instances with flipped
velocities.

- Improved actionAngle frequencies for circular orbits.

- Removed actionAngleFlat and actionAnglePower, because they are
superseded.

- Added hasC_dxdv member to Potential instances to indicate whether or
not they can be used with integrate_dxdv

- Add C implementation of PowerSphericalPotentialwCutoff;

- Moved MovingObjectPotential, BurkertPotential, and interpRZPotential
to top level; better implementation of interpRZPotential;

- Better handling of vo,ro, and solarmotion in Orbit instances (Orbit
initialization value is now used to generate RA, Dec, etc. outputs);

- Added --no-openmp installation option to allow installation without
OpenMP support (workaround for clang not supporting OpenMP; not
necessary anymore);

==================

- Initial release