coordinax

Coordinates in JAX

---

Coordinax enables calculations with coordinates in JAX. Built on Equinox and Quax.

Installation

pip install coordinax

Documentation

Quick example

import jax.numpy as jnp
import unxt as u
import coordinax as cx

q = cx.CartesianPos3D(
    x=u.Quantity(jnp.arange(0, 10.0), "kpc"),
    y=u.Quantity(jnp.arange(5, 15.0), "kpc"),
    z=u.Quantity(jnp.arange(10, 20.0), "kpc"),
)
print(q)
# <CartesianPos3D: (x, y, z) [kpc]
#     [[ 0.  5. 10.]
#      [ 1.  6. 11.]
#      ...
#      [ 8. 13. 18.]
#      [ 9. 14. 19.]]>

q2 = cx.vconvert(cx.SphericalPos, q)
print(q2)
# <SphericalPos: (r[kpc], theta[rad], phi[rad])
#     [[11.18   0.464  1.571]
#      [12.57   0.505  1.406]
#      ...
#      [23.601  0.703  1.019]
#      [25.259  0.719  0.999]]>

p = cx.CartesianVel3D(
    x=u.Quantity(jnp.arange(0, 10.0), "km/s"),
    y=u.Quantity(jnp.arange(5, 15.0), "km/s"),
    z=u.Quantity(jnp.arange(10, 20.0), "km/s"),
)
print(p)
# <CartesianVel3D: (x, y, z) [km / s]
#     [[ 0.  5. 10.]
#      [ 1.  6. 11.]
#      ...
#      [ 8. 13. 18.]
#      [ 9. 14. 19.]]>

p2 = cx.vconvert(cx.SphericalVel, p, q)
print(p2)
# <SphericalVel: (r[km / s], theta[km rad / (km s)], phi[km rad / (km s)])
#     [[ 1.118e+01 -3.886e-16  0.000e+00]
#      [ 1.257e+01 -1.110e-16  0.000e+00]
#      ...
#      [ 2.360e+01  0.000e+00  0.000e+00]
#      [ 2.526e+01 -2.776e-16  0.000e+00]]>


# Transforming between frames
icrs_frame = cx.frames.ICRS()
gc_frame = cx.frames.Galactocentric()
op = cxf.frame_transform_op(icrs_frame, gc_frame)
q_gc, p_gc = op(q, p)
print(q_gc, p_gc, sep="\n")
# <CartesianPos3D: (x, y, z) [kpc]
#     [[-1.732e+01  5.246e+00  3.614e+00]
#      ...
#      [-3.004e+01  1.241e+01 -1.841e+00]]>
# <CartesianVel3D: (x, y, z) [km / s]
#      [[  3.704 250.846  11.373]
#       ...
#       [ -9.02  258.012   5.918]]>

coord = cx.Coordinate({"length": q, "speed": p}, frame=icrs_frame)
print(coord)
# Coordinate(
#     data=KinematicSpace({
#        'length': <CartesianPos3D: (x, y, z) [kpc]
#             [[ 0.  5. 10.]
#              ...
#              [ 9. 14. 19.]]>,
#        'speed': <CartesianVel3D: (x, y, z) [km / s]
#             [[ 0.  5. 10.]
#              ...
#              [ 9. 14. 19.]]>
#     }),
#     frame=ICRS()
# )

print(coord.to_frame(gc_frame))
# Coordinate(
#     data=KinematicSpace({
#        'length': <CartesianPos3D: (x, y, z) [kpc]
#             [[-1.732e+01  5.246e+00  3.614e+00]
#              ...
#              [-3.004e+01  1.241e+01 -1.841e+00]]>,
#        'speed': <CartesianVel3D: (x, y, z) [km / s]
#             [[  3.704 250.846  11.373]
#              ...
#              [ -9.02  258.012   5.918]]>
#     }),
#     frame=Galactocentric( ... )
# )

Citation

If you found this library to be useful in academic work, then please cite.

Development

We welcome contributions!