Approaches class

Convenience class to get concatenated data for all galaxies. Mainly used when they are in close proximity and can appear on the same plot.

class galaxy.approaches.Approaches(snap=801, datadir=None, usesql=False, stride=1, ptype='lum')

A class to work with all 3 galaxies when in close proximity.

Args:

snap (int):

Snap number, equivalent to time elapsed. Defaults to the last timepoint.

datadir (str):

Directory to search first for the required file. Optional, and a default list of locations will be searched.

usesql (bool):

If True, data will be taken from a PostgreSQL database instead of text files.

stride (int):

Optional. For stride=n, get every nth row in the table. Only valid with usesql=True.

ptype (str):

can be ‘lum’ for disk+bulge, ‘dm’ for halo

Class attributes:

data (np.ndarray):

type, mass, position_xyz, velocity_xyz for each particle

read_db(stride)

Get relevant data from a PostgreSQL database and format it to be identical to that read from test files.

Args:

stride (int):

Optional. For stride=n, get every nth row in the table.

Changes:

self.time, self.particle_count and self.data are set.

Returns: nothing

xyz()

Convenience method to get positions as a np.array of shape (3,N)

vxyz()

Convenience method to get velocities as a np.array of shape (3,N)