dvdtau

zdm.cosmology.dvdtau(z)

Time-weighted volume element via linear interpolation (fast, array-compatible).

Includes (1+z)^-1 factor for source-frame to observer-frame rate conversion. Requires prior call to init_dist_measures() to populate lookup tables.

Parameters:

z (float or array_like) – Redshift(s). Must be within [ZMIN, ZMAX] set during initialization.

Returns:

Time-weighted volume element in Mpc^3 per unit redshift per steradian.

Return type:

float or ndarray