Do we need --mass-loss-prescription NONE (now ZERO)?

[jeffriley]

Users have the following choices for the option --mass-loss-prescription:

{NONE, ZERO, HURLEY, BELCZYNSKI2010, MERRITT2024}

(NONE is deprecated in favour of ZERO and will be removed at the end of 2024).

In the interests of reducing redundant/unnecessary options/option values, given that we can turn mass loss off with --use-mass-loss false, do we really need NONE/ZERO as options for --mass-loss-prescription? Running COMPAS with --use-mass-loss false produces the same results as running it with --mass-loss-prescription NONE or --mass-loss-prescription ZERO.

It seems a little odd to enable mass loss and then set the option to have no mass loss - why not just disable mass loss?

Versioning:

• COMPAS v03.01.06

[ilyamandel]

No objections to removing NONE/ZERO since we have the --user-mass-loss false option...
But my preference would actually be to reduce the total number of command-line possibilities, so I'd rather keep the option --mass-loss-prescription ZERO (since we have to have --mass-loss-prescription anyway), and instead remove --use-mass-loss false.

[LiekeVanSon]

We also have --overall-wind-mass-loss-multiplier which could be set to 0 to produce the same result in yet another way.

Also related I wonder what the behavior of DOMINANT_MASS_LOSS_RATE is for all different ways of setting the mass loss to zero? I also noticed that the documentation for dominant mass loss rate is now outdated, as it should reflect # enum class MASS_LOSS_TYPE: int { NONE, GB, LBV, OB, RSG, VMS, WR};

[jeffriley]

But my preference would actually be to reduce the total number of command-line possibilities, so I'd rather keep the
option --mass-loss-prescription ZERO (since we have to have --mass-loss-prescription anyway), and instead remove
--use-mass-loss false.

Happy to do that - I thought that might be considered too radical :-). We can deprecate --use-mass-loss and eventually remove it.

We also have --overall-wind-mass-loss-multiplier which could be set to 0 to produce the same result in yet another way.

Good point. Should we limit the multiplier to > 0 and <= some upper limit?

Also related I wonder what the behavior of DOMINANT_MASS_LOSS_RATE is for all different ways of setting the mass
loss to zero?

I can check that.

I also noticed that the documentation for dominant mass loss rate is now outdated, as it should reflect
enum class MASS_LOSS_TYPE: int { NONE, GB, LBV, OB, RSG, VMS, WR};

Thanks - we have some documentation updates, so I'll include that.

[ilyamandel]

Note on this.
--use-mass-loss false kills all mass loss, not just winds, including pulsational mass loss from TPAGB stars (which leads to very unphysical behaviour for these stars, since they need to reduce their mass to become WDs, but aren't allowed to).
I presume that --mass-loss-prescription NONE/ZERO would only kill wind mass loss, not pulsational mass loss. I think that's actually a "healthier" option, since it doesn't have the same non-physical artefacts.

[ilyamandel]

@jeffriley -- are you planning to deprecate --use-mass-loss and instead include --mass-loss-prescription ZERO?

[ilyamandel]

@jeffriley -- are you still planning to deprecate --use-mass-loss and instead include --mass-loss-prescription ZERO?