GEOS-Chem version numbering system

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This page describes the version numbering systems used by GEOS-Chem. We will transition from an alphanumeric system to a purely numeric versioning system with the v11-02-final release.

Alphanumeric versioning system (now retired)

GEOS-Chem versions v9-02 through v11-02 have used an alphanumeric version number system to denote major versions as opposed to intermediate checkpoint versions. The table below lists several previous GEOS-Chem versions that used the this system.

Action Resulting version #
GEOS-Chem 10 public release v10-01-public
First intermediate checkpoint of v11-01
  • New features and/or fixes added and validated with 1-month benchmark
v11-01a
Second intermediate checkpoint of v11-01
  • New features and/or fixes added and validated with 1-month benchmark
v11-01b
...etc Intermediate checkpoint versions... v11-02c thru v11-01k
v11-01 "provisional" release
  • The version prior to the final v11-01 release
  • Users were encouraged to download, test, report bugs
v11-01-provisional
GEOS-Chem v11-01 "public" release v11-01-public
First intermediate checkpoint version of v11-02
  • New features and/or fixes added and validated with 1-month benchmark
v11-02a
Second intermediate checkpoint version of v11-02
  • New features and/or fixes added and validated with 1-month benchmark
v11-02b
...etc intermediate checkpoint versions ... v11-02c thru v11-01f
v11-02 "release candidate"
  • Formerly called "provisional"
  • Users were encouraged to download, test, report bugs
v11-02-release-candidate
GEOS-Chem v11-02 final release
  • Formerly called "public", but this practice has been discontinued
v11-02-final


NOTES:

  1. All intermediate checkpoint versions were validated with a 1-month benchmark. Some intermediate checkpoint versions were validated with both 1-month and 1-year benchmarks. For clarity, we have not denoted the checkpoint releases for which 1-year benchmarks were also done.
  2. We have listed the version numbers in the table from oldest at the top to newest at the bottom. This more clearly shows the progression of version numbers. Note that this is the opposite of how versions are displayed in the Git history.

Limitations of the alphanumeric system

Prior to GEOS-Chem v11-02, intermediate checkpoint versions were not made available to GEOS-Chem users. Because of this, the last version in a series was always denoted as the "public" release (e.g v9-02-public, v10-01-public, etc.). This made sense at the time, because the "public" version was the version that GEOS-Chem users would would be able to download. The GEOS-Chem manual was only updated for each "public" version.

We have since discontinued the term "public version", as GEOS-Chem users are now invited to download any intermediate checkpoint release when starting a research project. The last version in the v11-02 series will now be named v11-02-final.

The practice of issuing a "provisional" or "release candidate" version immediately prior to the "final" release in a series began with GEOS-Chem v9-02. This was intended as a way of allowing users to take the "release candidate" version for a test-drive and to report any bugs or issues to the GEOS-Chem Support Team. The GCST would then be able to fix the issues for the "final" release.

While this versioning system worked well, it is not in line with accepted software industry best practice. Also the change in terminology from "public" to "final" and from "provisional" to "release candidate", while well-intentioned, can lead to confusion. Furthermore, an intermediate checkpoint version number such as v11-02c does not distinguish between the addition of new features as opposed to bug fixes. For these reasons, we are migrating to a purely numeric version numbering system, as discussed in the following section.

--Bob Yantosca (talk) 20:47, 14 June 2018 (UTC)

Numeric versioning system

In order to transition between the alphanumeric and numeric versioning systems, the upcoming GEOS-Chem release v11-02-final will also carry the version number 12.0.0.

In order to conform more closely to industry-standard software versioning protocol, we shall retire the use of alphanumeric version numbers (e.g. v11-02a) for GEOS-Chem. Instead we shall adopt purely numeric version descriptors of the form X.Y.Z, as described in the table below. (This system is loosely based on the idea of Semantic Versioning.)

Number Description When is this digit incremented?
X Major version number.
  • Analogous to previously-termed "public" releases
X is incremented when we introduce an update that immediately breaks backward compatibility with the previous series of GEOS-Chem versions.

Examples of when the major number was changed in past versions of GEOS-Chem:

  • Replacing old emissions code (v9-02) with HEMCO (v10-01)
  • Replacing the SMVGEAR chemistry solver (v10-01) to FlexChem/KPP (v11-01)
Y Benchmark number (aka feature number)
  • Denotes a collection of new features
  • Analogous to previous lettered versions
Y changes when a new set of features is validated with a 1-month benchmark.
  • Some (but not all) Y versions will have an associated 1-year benchmark.

NOTE: Any change to a GEOS-Chem run directory (that is, modifying input.geos, HEMCO_Config.rc, HISTORY.rc, etc.) necessitates that Y be incremented.

Z Bug fix number (aka patch number) Z changes when the following types of updates are added to the code:
  • Fixes for specialty simulations that do not affect the full-chemistry benchmark simulations
  • Fixes for bugs or technical issues that do not break backwards compatibility with the last benchmarked version (e.g. X.Y.0)

NOTE: All patched X.Y.Z versions of GEOS-Chem will remain compatible with the run directories from the last benchmarked version (X.Y.0).

--Bob Yantosca (talk) 18:59, 14 June 2018 (UTC)

Example

A sample progression of GEOS-Chem version numbers using the purely numeric versioning system is illustrated in the table below.

Action Resulting version #
The GEOS-Chem v11-02 major release is issued v11-02-final, aka 12.0.0
A bug is fixed, but does not break backwards compatibility 12.0.1
A collection of new features is added
  • and validated with a 1-month benchmark
  • and maybe with a 1-year benchmark (if necessary)
12.1.0
A bug identified during the benchmark is fixed 12.1.1
Another bug dentified during the benchmark is fixed 12.1.2
Another collection of new features is added
  • and validated with a 1-month benchmark
  • and maybe with a 1-year benchmark (if necessary)
12.2.0
A bug identified during the benchmark is fixed 12.2.1
...etc. 12.Y.Z
The next GEOS-Chem "release candidate" is issued
  • aka The version immediately preceding the next major release
  • Users are encouraged to download and test and report bugs/issues
12.N.0 (N is TBD)
The next major version of GEOS-Chem is released 13.0.0


NOTES:

  1. We have listed the version numbers in the table from oldest at the top to newest at the bottom. This more clearly shows the progression of version numbers. Note that this is the opposite of how versions are displayed in the Git history.

--Bob Yantosca (talk) 14:40, 15 June 2018 (UTC)

Documentation

The GEOS-Chem manual will be rewritten for each "major" release X.0.0. But the GEOS-Chem wiki will be updated for each benchmark and patch version X.Y.Z. Since GEOS-Chem v11-01, much of the GEOS-Chem manual now points to information on the GEOS-Chem wiki.

GEOS-Chem users will no longer need to wait for a major release (X.0.0), but instead can download the most recent version (X.Y.Z) when starting a new research project.

--Bob Yantosca (talk) 20:56, 14 June 2018 (UTC)