poet/README.md

POET

POET is a coupled reactive transport simulator implementing a parallel architecture and a fast distributed hash table.

External Libraries

We use external libraries:

• argh - https://github.com/adishavit/argh (BSD license)

Installation

Requirements

To compile POET you need several software to be installed:

• C/C++ compiler (tested with GCC)
• MPI-Implementation (tested with OpenMPI and MVAPICH)
• R language and environment
• CMake 3.9+

If documantiation should be build during compilation doxygenand graphviz must be provided too.

The following R libraries must then be installed:

• devtools
• Rcpp
• RInside
• RedModRphree
• Rmufits

Compiling source code

The generation of makefiles is done with CMake. So, running

cmake . -B build

will create the directory build. cd into it and run make to start build process.

If everything went well you'll find the executable at build/src/poet.

During the generation of Makefiles, various options can be specified via cmake -D <option>=<value> [...]. Currently there are the following available options:

• DHT_Debug=boolean - toggles the output of detailed statistics about DHT usage (cmake -D DHT_Debug=ON). Defaults to OFF.
• BUIL_DOC=boolean - toggles the generation of documantiation during compilation process. Defaults to ON.

Example: Build from scratch

Assuming that only the C/C++ compiler, MPI libraries, R runtime environment and CMake have been installed, POET can be installed as follows:

# start R environment
$ R

# install R dependencies
> install.packages(c("devtools", "Rcpp", "RInside"))
> devtools::install_git("https://gitext.gfz-potsdam.de/delucia/RedModRphree.git")
> devtools::install_git("https://gitext.gfz-potsdam.de/delucia/Rmufits.git")
> q(save="no")

# cd into POET project root
$ cd <POET_dir>

# Build process
$ mkdir build && cd build
$ cmake -DCMAKE_INSTALL_PREFIX=/home/<user>/poet ..
$ make -j<max_numprocs>
$ make install

This will install a POET project structure into /home/<user>/poet which is called hereinafter <POET_INSTALL_DIR>. With this version of POET I would not recommend to install to hierarchies like /usr/local/ etc.

The correspondending directory tree would look like this:

.
└── poet/
    ├── bin/
    │   └── poet
    ├── data/
    │   └── SimDol2D.R
    ├── docs/ 
    │    └── html/
    │       ├── index.html
    │       └── ...
    └── R_lib/
        ├── kin_r_library.R
        └── parallel_r_library.R

The R libraries will be read in during runtime and the paths are hardcoded absolute paths inside poet.cpp. So, if you consider to move bin/poet either change paths of the R source files and recompile POET or also move R_lib/* according to the binary.

To display the generetated html documentation just open docs/html/index.html with the browser of your choice.

Running

Before POET is ready to run, a working directory must be created. In this directory you should find the executable file, the R scripts <POET_ROOT>/R_lib/kin_r_library.R and <POET_ROOT>/R_lib/parallel_r_library.R and the simulation description e.g. <POET_ROOT>/data/chem_problems/SimDol2D.R.

Run POET by mpirun ./poet <OPTIONS> <SIMFILE> <OUTPUT_DIRECTORY> where:

• OPTIONS - runtime parameters (explained below)
• SIMFILE - simulation described as R script (currently supported: <POET_INSTALL_DIR>/data/SimDol2D.R)
• OUTPUT_DIRECTORY - path, where all output of POET should be stored

Runtime options

The following parameters can be set:

Option	Value	Description
-work-package-size=	1..n	size of work packages (defaults to 5)
-ignore-result		disables store of simulation resuls
-dht		enabling DHT usage (defaults to OFF)
-dht-nolog		disabling applying of logarithm before rounding
-dht-signif=	1..n	set rounding to number of significant digits (defaults to 5)
-dht-strategy=	0-1	change DHT strategy. NOT IMPLEMENTED YET (Defaults to 0)
-dht-size=	1-n	size of DHT per process involved in byte (defaults to 1 GiB)
-dht-snaps=	0-2	disable or enable storage of DHT snapshots
-dht-file=	<SNAPSHOT>	initializes DHT with the given snapshot file

Additions to dht-signif

Only used if no vector is given in setup file. For individual valuies per column use R vector signif_vector in SIMFILE.

Additions to dht-snaps

Following values can be set: - 0 = snapshots are disabled - 1 = only stores snapshot at the end of the simulation with name <OUTPUT_DIRECTORY>.dht - 2 = stores snapshot at the end and after each iteration iteration snapshot files are stored in /iter.dht

Example: Running from scratch

We will continue the above example and start a simulation with SimDol2D.R, which is the only simulation supported at this moment. To start the simulation with 4 processes cd into your previously installed POET-dir <POET_INSTALL_DIR>/bin and run:

mpirun -n 4 ./poet ../data/SimDol2D.R output

After a finished simulation all data generated by POET will be found in the directory output.

You might want to use the DHT to cache previously simulated data points and reuse them in further time-steps. Just append -dht to the options of POET to activate the usage of the DHT. The resulting call would look like this:

mpirun -n 4 ./poet -dht SimDol2D.R output

Examples included (more to come)

• SimDol2D.R - simple chemistry (Calcite/Dolomite) on a 50x50 2D grid, 20 time steps 2)
• ~SimDolKtz.R - simple chemistry (Calcite/Dolomite) on Ketzin grid (650k elements), 20 time steps The flow snapshots are NOT INCLUDED in project directory but must be provided separately. At this moment SimDolKtz.R is not supported.

About the usage of MPI_Wtime()

Implemented time measurement functions uses MPI_Wtime(). Some important informations from the OpenMPI Man Page:

For example, on platforms that support it, the clock_gettime() function will be used to obtain a monotonic clock value with whatever precision is supported on that platform (e.g., nanoseconds).