Hello. I gave a look to the manual; the many new features of v54 are scattered throughout the document, so not very clear at first glance.
So, beside this new manual, I think it would be helpful a short summary document (just few pages) outlining all the differences v54/cv50 in few points, e.g.:
1) Physics processes. Is the description of CR physical processes (transport, interactions) changed? Where?
2) Physics inputs. Nuclear data files changes (which channel added), ISRF, HI, CO files. Quantities in E-loss routines.
3) Parametrizations. Differences in source spectra & spatial distribution, gas distribution, B-field models, cross section parametrization routines.
4) Technical aspects. (less important) Memory management or code organization; interfaces with eg. Galdef format.

thanks for the comments, this feedback on the Explanatory Supplement is very useful.
as before there is place for this under BUGS, goto galprop code and category Manual.
Meanwhile some answers...
I don't want to make a separate document since 'do everything in one place' seems a good motto.
But there can be special sections for what you suggest, e.g. summaries of differences.

You are right that the differences are scattered, just as they are throughout in code.
I thought they were most usefully described at the places in the document where they come up.
It would be hard now to list all the differences since v54 has been going on a few years now.
I will revise the relevant sections as far as possible, but really should go now for v54 and not worry too much about what changed.

1) physics processes are not changed.
2) nuclear physics channels have been updated but not documented in the Exp.Supp. There is a paper which can be referenced meanwhile.
the ISRF changed at lot, but has not been written up yet.
HI, CO changed, not yet written up.
E-loss routines unchanged.

3) some of these are documented, some not.
4) a start has been made on the code architecture, at a high level.
also some more very detailed description of the more important propagation routines has been added.
for the GALDEF parameters, this is done per parameter which I think is most useful.

Note that documentation is a never-ending task especially with code being steadily updated, and people find it more fun to write code than to write it up.

I am going to cc this to BUGS, stay tuned.

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Andy Strong, MPE

Yes; I see section 8 of the present manual is something like what I meant, but it should bee expanded and more detailed (I assume it is in progress, anyway).
NB - these are just my comments/suggestions. Not "requests".

comments/suggestions or even requests are all welcome !

_________________
Andy Strong, MPE

shifting to BUGS here:
http://galprop.stanford.edu/bugs/show_bug.cgi?id=40

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Andy Strong, MPE