Installation instructions

MetaWards is a Python package, but it does come with R wrappers. This means that you can choose to install MetaWards either via Python or via R. Note that MetaWards depends on data files that are held in MetaWardsData. To use MetaWards, you must install MetaWardsData following these instructions.

Installation via Python

MetaWards is compiled and tested on Windows, Linux and OS X, but should be able to compile and install on any operating system with a working Python >= 3.7 and a C compiler.

To install MetaWards, you first need to install Python >= 3.7. To check if you have Python 3.7 installed type;

python -V

This should print out the version number of the Python you have available. If the version number is 2.??? then you have a very old Python 2. If this is the case, try;

python3 -V

and see if you have a Python 3 that has a version number >= 3.7. If so, please use python3 instead of python.

If you don’t have Python >=3.7 installed, then you can install Python either via your package manager, or more simply, by using anaconda.

Once you have a working Python >= 3.7, the easiest way to install MetaWards is using pip.

pip install metawards

(if this doesn’t work, then you may need to use the command pip3, or you may have to install pip. If you have trouble installing pip then we recommend that you download and install anaconda, which has pip included)

To install a specific version, e.g. 1.5.1, type

pip install metawards==1.5.1

This will install a binary version of metawards if it is available for your operating system / processor / version of python. If not, then the metawards pyx code that was compiled into C using cython, will be compiled into an executable using your system C compiler (e.g. gcc or clang). You can control which C compiler to use by setting the CC environment variable, e.g.

CC=gcc pip install metawards

MetaWards is written in standard C, using OpenMP for parallelisation, and it has no external dependencies, so it should compile without issue. Note that the system C compiler on OS X (Mac) does not support OpenMP. In this case you the code will compile with OpenMP disabled. If you want to use all of the cores of your computer than you will need to install a different compiler, e.g. installing clang via homebrew. If you have any problems then please post an issue on GitHub.

Once installed, you can run metawards by typing

metawards --version

This should print out some version information about MetaWards, including whether or not it found MetaWardsData.

If this doesn’t work, then it is possible that the directory into which metawards has been placed is not in your PATH (this is quite common on Windows). You can find the location of the metawards executable by starting Python and typing;

> import metawards
> print(metawards.find_mw_exe())

You can then run metawards either by typing out the full path to the executable that is printed, or by adding the directory containing the executable to your PATH.

Installation via R

MetaWards can be used within R via the reticulate package. We have built a MetaWards R package that simplifies this use.

To use this, you must first have installed metawards as above, via the Python route. This is because the version of Python used by default in R is too old to run MetaWards (MetaWards needs Python 3.7 or newer, while the default in reticulate is to install and use Python 3.6).

Once you have MetaWards (and MetaWardsData) installed in Python, you first need to get the reticulate command that you will need to tell R which Python interpreter to use. We have written a function to do this for you. Open Python and type;

import metawards
print(metawards.get_reticulate_command())

You should see printed something like

reticulate::use_python("/path/to/python", required=TRUE)

where /path/to/python is the full path to the python executable that you are using.

Next, open R or RStudio and install reticulate (if you haven’t done that already).

> install.packages("reticulate")

Next, you should install the MetaWards R package from GitHub. You need to use the devtools library to do this.

> library(devtools)
> install_github("metawards/rpkg")

Next, you need to tell reticulate to use the Python executable you found earlier. Copy in the reticulate command exactly as it was printed by Python, e.g.

> reticulate::use_python("/path/to/python", required=TRUE)

Next, load the metawards package and use the py_metawards_available to check that MetaWards can be found and loaded.

> metawards::py_metawards_available()
[1] TRUE

Note

In the future, once reticulate defaults to Python 3.7 or above, you will be able to install MetaWards directly by calling metawards::py_install_metawards(). This command will install metawards into the default Python that comes with reticulate.

Once installed, you can check if there are any updates to MetaWards available directly in R, via;

> metawards::py_metawards_update_available()

and you can update to the lastest version using;

> metawards::py_update_metawards()

Source install

You can download a source release of MetaWards from the project release page.

Once you have downloaded the file you can unpack it and change into that directory using;

tar -zxvf MetaWards-X.Y.Z.tar.gz
cd MetaWards-X.Y.Z

where X.Y.Z is the version you downloaded. For the 1.4.0 release this would be;

tar -zxvf MetaWards-1.4.0.tar.gz
cd MetaWards-X.Y.Z

Next you need to install the dependencies of MetaWards. Do this by typing;

pip install -r requirements.txt

Now you are ready to compile and install MetaWards itself;

make
make install

You can choose the C compiler to use by setting the CC environment variable, e.g.

CC=clang make
CC=clang make install

MetaWards is written in standard C, using OpenMP for parallelisation, and it has no external dependencies, so it should compile without issue. Note that the system C compiler on OS X (Mac) does not support OpenMP. In this case you the code will compile with OpenMP disabled. If you want to use all of the cores of your computer than you will need to install a different compiler, e.g. installing clang via homebrew. If you have any problems then please post an issue on GitHub.

Just as for the normal Python install you may need to use the find_mw_exe() function to find the full path to the installed metawards executable if this hasn’t been placed in your PATH.

For developers

You can clone the MetaWards repository to your computer and install from there;

git clone https://github.com/metawards/MetaWards
cd MetaWards
pip install -r requirements-dev.txt

From this point you can compile as if you have downloaded from source. As a developer you may want to run the tests and create the website. To do this type;

pytest tests
make doc

There are shortcuts for running the quick or slow tests, e.g.

make test
make quicktest

Note that the tests assume that you have already downloaded the model data from MetaWardsData and configured this as described here.