## Comet parameter: peptide_mass_units

- This parameter controls the units applied to the peptide_mass_tolerance parameter.
- Valid values are 0, 1, and 2.
- Set this parameter to 0 for amu.
- Set this parameter to 1 for mmu.
- Set this parameter to 2 for ppm.
- The default value is "0" if this parameter is missing.

Example:
`peptide_mass_units = 0`
`peptide_mass_units = 1`
`peptide_mass_units = 2`