updated default value listed in --maximum-evolution-time

[FloorBroekgaarden]

there is a minor type in the documentation and YAML file for --maximum-evolution-time

the default YAML file says "maximum-evolution-time: 14021.28" (https://github.com/TeamCOMPAS/COMPAS/blob/dev/compas_python_utils/preprocessing/compasConfigDefault.yaml ) but the online documentation says:
--maximum-evolution-time
Maximum time to evolve binaries (Myr). Evolution of the binary will stop if this number is reached. Default = 13700.0

The correct value is 14031, which is the value that one obtains when you take the HUBBLE_TIME value from src/constants.h (and use the default definition from src/Options.cpp which defines maximum-evolution-time as: m_MaxEvolutionTime > HUBBLE_TIME / SECONDS_IN_MYR, which leads to 14031 Myr as the default (The 14021.28 Myr value comes from doing the same calculations but rounding values early on). More precisely, the calculation is: 1/ (67.8 * 1000.0 / (3.0* 10^(22))) seconds to Myr = 14031 Myr , with 67.8 from WMAP from the constant.h defaults.

Again, not a big deal, just a rounding of the value/typo. So a very minor fix

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[ilyamandel]

Thanks, @FloorBroekgaarden !
Though it really shouldn't be the Hubble time -- it should be the age of the Universe, and the Hubble time is only an approximation to that (the integral in https://en.wikipedia.org/wiki/Age_of_the_universe#Definition is not quite 1).
The WMAP age of the Universe was closer to 13.7 Gyr.
Can I suggest we use 13.8 Gyr everywhere, consistent with both the WMPA and Planck values (see, e.g., the same wikipedia page)?

[FloorBroekgaarden]

I like that solution/suggestion! This also reduced the number of calculations.
I'm currently traveling without a laptop but will push it when Im back (before Monday).

[ilyamandel]

@FloorBroekgaarden -- gentle ping :)

[ilyamandel]

You haven't actually changed the code, @FloorBroekgaarden :

Options.cpp: m_MaxEvolutionTime = HUBBLE_TIME / SECONDS_IN_MYR; //13700.0;

[FloorBroekgaarden]

whoops, thanks!
Do we want to keep COMPLAIN_IF(m_MaxEvolutionTime > 13800, "Maximum evolution time in Myr (--maxEvolutionTime) must be <= " + std::to_string(13800) + " Myr");
?

On one hand it might be nice to keep this to stop the simulation from running for COMPAS users who accidentally set the max evolution to a too large value, though, of course, it's technically not forbidden to evolve binaries beyond this max evolution time (e.g., if someone wants to calculate population characteristics for the future Universe).

[ilyamandel]

I can see arguments for dropping the check if the user knows what they want; on the other hand, the check prevents confused readers from accidentally taking too long while running slow binaries, as you say... Let's leave it for now, since we haven't run into a case when it's a problem yet. One final request: since you've now (rightly) edited the C++ code, you should increase the version number and add a comment in changelog.h.

[jeffriley]

m_MaxEvolutionTime is declared as a double on Options.h. It's good c++ coding practice to
set the value to 13800.0 in Options.cpp rather than just 13800.

Similarly, the value in the yaml file should be a floating point number, not an integer.

[ilyamandel]

Note that you should auto-generate the yaml file with --create-YAML-file