Climate models are normally built to do real science; that is not my aim. Rather, I want something which will form a component of an educational game which allows players to make policy decisions to attempt to maintain the climate within ‘safe’ limits, given constraints of population, consumption, demand for strategic materials and so on.
Consequently, I need the model to run on ordinary PCs that people may be expected to have, or even perhaps on something like an X Box. It also needs to be able to simulate a year in at most about twenty minutes, with enough processor cycles free to run user interface code.
It’s quite likely that no existing climate model will work under these constraints.
|ClimateMachine||Julia||Apache License v2.0||Released||Present||Failing, probably fixable.
|Community Earth System Model||Fortran, C, Python, Perl||BSD-style||Released||Present||Failing|
|Hector||C++, R||GPL v3||Released||Present||Apparently successful|
|E3SM||Fortran, C||BSD Style||Not suitable for consumer-grade machines||Present||Not attempted|
|atlas||C, Fortran||Apache License v2.0||Probably too low level||Minimal||Not attempted|
|Isca||Fortran, Python||GPL v3||Released||Present||Apparently successful, documentation slightly wrong|
Build failed with the following output:
ERROR: LoadError: UndefVarError: LLVMPtr not defined Stacktrace:  include(::Module, ::String) at ./Base.jl:377  top-level scope at none:2  eval at ./boot.jl:331 [inlined]  eval(::Expr) at ./client.jl:449  top-level scope at ./none:3 in expression starting at /home/simon/.julia/packages/CUDA/wTQsK/src/CUDA.jl:9 ERROR: LoadError: LoadError: Failed to precompile CUDA [052768ef-5323-5732-b1bb-66c8b64840ba] to /home/simon/.julia/compiled/v1.4/CUDA/oWw5k_BxRo2.ji. Stacktrace:  error(::String) at ./error.jl:33  compilecache(::Base.PkgId, ::String) at ./loading.jl:1272  _require(::Base.PkgId) at ./loading.jl:1029  require(::Base.PkgId) at ./loading.jl:927  require(::Module, ::Symbol) at ./loading.jl:922  include(::Module, ::String) at ./Base.jl:377  include(::String) at /home/simon/tmp/climate/ClimateMachine.jl/src/ClimateMachine.jl:1  top-level scope at /home/simon/tmp/climate/ClimateMachine.jl/src/ClimateMachine.jl:12  include(::Module, ::String) at ./Base.jl:377  top-level scope at none:2  eval at ./boot.jl:331 [inlined]  eval(::Expr) at ./client.jl:449  top-level scope at ./none:3 in expression starting at /home/simon/tmp/climate/ClimateMachine.jl/src/Arrays/MPIStateArrays.jl:3 in expression starting at /home/simon/tmp/climate/ClimateMachine.jl/src/ClimateMachine.jl:12
The error appears to be caused by a problem in Julia’s CUDA library, which should hand off computation to my graphics processor (which would be a good thing as this has some serious compute power).
All tests also fail, but that is almost certainly because the build failed.
This is probably fixable without a huge amount of effort.
Overall, although I have no experience with Julia, the codebase looks very clean and well designed. The installation process was big and complex, but ran commendably cleanly, with no installation problems.
Community Earth System Model
The build instructions appear to be incomplete. Nothing compiles. There is no executable product. I don’t even know where to start with attempting to investigate further.
Pure R build appeared to work cleanly, but I didn’t understand what I’d got sufficiently to carry out any meaningful tests. I think it worked.
Makefile (standalone) build also appeared to build satisfactory, produced an executable, and I was able to use this to do a test run, but again I don’t understand what I’m doing sufficiently to understand what I got. Still, this is promising.
From the documentation it appeared exceedingly unlikely that E3SM would run satisfactorily on the hardware available to me, so I didn’t attempt this
I think Atlas is probably a useful library for people who know how to build climate models, but I think it’s too low level for what I want to do. Build was not attempted.
Installation/build appeared to work correctly, but there was a slight error with the build documentation.
Where the documentation says to run
(isca_env)$ pip install -e .
I got the following error:
(isca_env) simon@mason:~/tmp/climate/Isca$ pip install -e . Obtaining file:///home/simon/tmp/climate/Isca ERROR: file:///home/simon/tmp/climate/Isca does not appear to be a Python project: neither 'setup.py' nor 'pyproject.toml' found.
I found a
setup.py file under
src/extra/python/, so I ran
pip install -e src/extra/python/
This gave the following output:
Obtaining file:///home/simon/tmp/climate/Isca/src/extra/python Preparing metadata (setup.py) ... done Requirement already satisfied: sh in /home/simon/bin/miniforge3/envs/isca_env/lib/python3.9/site-packages (from Isca==0.2) (1.13.1) Requirement already satisfied: jinja2 in /home/simon/bin/miniforge3/envs/isca_env/lib/python3.9/site-packages (from Isca==0.2) (3.0.3) Requirement already satisfied: f90nml in /home/simon/bin/miniforge3/envs/isca_env/lib/python3.9/site-packages (from Isca==0.2) (1.3.1) Requirement already satisfied: numpy in /home/simon/bin/miniforge3/envs/isca_env/lib/python3.9/site-packages (from Isca==0.2) (1.21.4) Requirement already satisfied: pandas in /home/simon/bin/miniforge3/envs/isca_env/lib/python3.9/site-packages (from Isca==0.2) (1.3.4) Requirement already satisfied: xarray in /home/simon/bin/miniforge3/envs/isca_env/lib/python3.9/site-packages (from Isca==0.2) (0.20.1) Requirement already satisfied: MarkupSafe>=2.0 in /home/simon/bin/miniforge3/envs/isca_env/lib/python3.9/site-packages (from jinja2->Isca==0.2) (2.0.1) Requirement already satisfied: python-dateutil>=2.7.3 in /home/simon/bin/miniforge3/envs/isca_env/lib/python3.9/site-packages (from pandas->Isca==0.2) (2.8.2) Requirement already satisfied: pytz>=2017.3 in /home/simon/bin/miniforge3/envs/isca_env/lib/python3.9/site-packages (from pandas->Isca==0.2) (2021.3) Requirement already satisfied: six>=1.5 in /home/simon/bin/miniforge3/envs/isca_env/lib/python3.9/site-packages (from python-dateutil>=2.7.3->pandas->Isca==0.2) (1.16.0) Installing collected packages: Isca Running setup.py develop for Isca Successfully installed Isca-0.2
So I think that worked satisfactorily. To test it I then attempted to run a test case, and this failed complaining about missing environment variables. So I think this is working and I just need to read the documentation better to get it running.
It needs to be said this was also a very big, complex installation process and the fact that it all ran cleanly is very commendable: this isn’t easy.
All climate models are complex bits of software, and, being mathematically intensive, tend to be written in relatively special purpose languages (R, Julia, Fortran) with which I’m not familiar. I’m also intensely prejudiced against Python, because I hate significant white space, so again where systems use Python as a front end scripting language, this isn’t familiar to me.
Hector and Isca built
satisfactorily without much difficulty. Hector
successfully ran test cases (and commendably quickly), although
it didn’t produce output I am able to interpret at this
stage. **Climate Machine** didn't build, but I think this is fixable with a little more work.
All three of these systems are promising and worthy of further investigation. Whether any will do what I need I am not yet certain.