Pulsar formed from stellar merger product not recorded in BSE_Pulsar_Evolution

[SimonStevenson]

Describe the bug
Pulsar formed from stellar merger product not recorded in BSE_Pulsar_Evolution

This is similar to issue #1317 I posted recently.

I think I have tracked this down and have a solution. Will post a PR shortly.

The EVOLUTION_STATUS in BaseBinaryStar::Evolve was recorded as MASSLESS_REMNANT due to the IsMRandRemant() check. I have added an additional check to see if the user is evolving pulsars, and if so if the stellar remnant is a neutron star, then keep evolving.

Once I had done this, I found that I got hundreds of thousands of 1 Myr time steps. I tracked this down to MR.h which has CalculateTimestep rather than ChooseTimestep. Fixing this resolved this issue.

I have also added a check to see if the binary is bound to BaseBinaryStar::ChooseTimestep so that the GW and tides stuff is not evaluated for merged/unbound binaries.

Label the issue
Please label the 'severity' and 'urgency' of this issue. You can choose:

urgency_moderate - This is a moderately urgent issue
severity_moderate - This is a moderately severe bug

To Reproduce
This is the system I have been using to test this:

./COMPAS -n 1 --mode BSE --initial-mass-1 14.0 --initial-mass-2 1.0 --semi-major-axis 0.1 --evolve-main-sequence-merger TRUE --evolve-pulsars TRUE --pulsar-birth-magnetic-field-distribution LOGNORMAL --pulsar-birth-spin-period-distribution UNIFORM --radial-change-fraction 0.01 --remnant-mass-prescription FRYER2012

Expected behavior
Pulsar should be recorded in BSE_Pulsar_Evolution.

Versioning (please complete the following information):

• OS: MacOS v 12.4
• COMPAS v03.12.00

[ilyamandel]

Thank you for fixing this with #1325 , @SimonStevenson !