# Cosmology Parameters

`ComovingCoordinates` (external)
- Flag (1 - on, 0 - off) that determines if comoving coordinates are
used or not. In practice this turns on or off the entire cosmology
machinery. Default: 0
`CosmologyFinalRedshift` (external)
- This parameter specifies the redshift when the calculation will
halt. Default: 0.0
`CosmologyOmegaMatterNow` (external)
- This is the contribution of all non-relativistic matter (including
HDM) to the energy density at the current epoch (z=0), relative to
the value required to marginally close the universe. It includes
dark and baryonic matter. Default: 0.279
`CosmologyOmegaLambdaNow` (external)
- This is the contribution of the cosmological constant to the energy
density at the current epoch, in the same units as above. Default:
0.721
`CosmologyHubbleConstantNow` (external)
- The Hubble constant at z=0, in units of 100 km/s/Mpc. Default:
0.701
`CosmologyComovingBoxSize` (external)
- The size of the volume to be simulated in Mpc/h (at z=0). Default:
64.0
`CosmologyInitialRedshift` (external)
- The redshift for which the initial conditions are to be generated.
Default: 20.0
`CosmologyMaxExpansionRate` (external)
- This float controls the timestep so that cosmological terms are
accurate followed. The timestep is constrained so that the relative
change in the expansion factor in a step is less than this value.
Default: 0.01
`CosmologyCurrentRedshift` (information only)
- This is not strictly speaking a parameter since it is never
interpreted and is only meant to provide information to the user.
Default: n/a