Installation

Obtaining `chombo-discharge`

chombo-discharge can be freely obtained from https://github.com/chombo-discharge/chombo-discharge. The following packages are required:

Chombo, which is supplied with chombo-discharge.
The C++ JSON file parser https://github.com/nlohmann/json.
The EBGeometry package, see https://github.com/rmrsk/EBGeometry.
LAPACK and BLAS

The Chombo, nlohmann/json, and EBGeometry dependencies are automatically handled by chombo-discharge through git submodules.

Warning

Our version of Chombo is hosted at https://github.com/chombo-discharge/Chombo-3.3.git. chombo-discharge has made substantial changes to the embedded boundary generation in Chombo. It will not compile with other versions of Chombo than the one above.

Optional packages are

A serial or parallel version of HDF5, which is used for writing plot and checkpoint files.
An MPI installation, which is used for parallelization.
https://visit-dav.github.io/visit-website/ visualization, which used for visualization.

Cloning `chombo-discharge`

When compiling chombo-discharge, makefiles must be able to find both chombo-discharge and Chombo. In our makefiles the paths to these are supplied through the environment variables

DISCHARGE_HOME, pointing to the chombo-discharge root directory.
CHOMBO_HOME, pointing to your Chombo library

Note that DISCHARGE_HOME must point to the root folder in the chombo-discharge source code, while CHOMBO_HOME must point to the lib/ folder in your Chombo root directory. When cloning with submodules, both Chombo and nlohmann/json will be placed in the Submodules folder in $DISCHARGE_HOME.

Tip

To clone chombo-discharge directly to $DISCHARGE_HOME, set the environment variables and clone (using --recursive to fetch submodules):

export DISCHARGE_HOME=/home/foo/chombo-discharge
export CHOMBO_HOME=$DISCHARGE_HOME/Submodules/Chombo-3.3/lib

git clone --recursive git@github.com:chombo-discharge/chombo-discharge.git ${DISCHARGE_HOME}

Alternatively, if cloning using https:

export DISCHARGE_HOME=/home/foo/chombo-discharge
export CHOMBO_HOME=$DISCHARGE_HOME/Submodules/Chombo-3.3/lib

git clone --recursive https://github.com/chombo-discharge/chombo-discharge.git ${DISCHARGE_HOME}

chombo-discharge is built using a configuration file supplied to Chombo. This file must reside in $CHOMBO_HOME/mk. Some standard configuration files are supplied with chombo-discharge, and reside in $DISCHARGE_HOME/Lib/Local. These files may or may not work right off the bat.

Test build

For a quick compilation test the user can use the GNU configuration file supplied with chombo-discharge by following the steps below.

Copy the GNU configuration file

cp $DISCHARGE_HOME/Lib/Local/Make.defs.GNU $CHOMBO_HOME/mk/Make.defs.local

If you do not have the GNU compiler suite, install it by
```
sudo apt install csh gfortran g++ libblas-dev liblapack-dev
```
This will install
- LAPACK and BLAS
- GNU compilers for Fortran and C++
Compile chombo-discharge
```
cd $DISCHARGE_HOME
make -s -j4
```

This will compile the chombo-discharge source code in serial and without HDF5 (using four cores for the compilation). If successful, chombo-discharge libraries will appear in $DISCARGE_HOME/Lib.

Full configuration

chombo-discharge is compiled using GNU Make, following the Chombo configuration methods.

Important

Compilers, libraries, and configuration options are defined in a file Make.defs.local which resides in $CHOMBO_HOME/mk. Users need to supply this file in order to compile chombo-discharge.

Typically, a full configuration consists of specifying

Fortran and C++ compilers
Specifying configurations. E.g., serial or parallel builds, and compiler flags.
Library paths (in particular for HDF5).

Main settings

The main variables that the user needs to set are

DIM = 2/3 The dimensionality (must be 2 or 3).
DEBUG = TRUE/FALSE This enables or disables debugging flags and code checks/assertions.
OPT = FALSE/TRUE/HIGH. Setting OPT=TRUE/HIGH enables optimization flags that will speed up Chombo and chombo-discharge.
PRECISION = DOUBLE Currently, chombo-discharge has not been wetted with single precision. Many algorithms (like conjugate gradient) depend on the use of double precision.
CXX = <C++ compiler>
FC = <Fortran compiler>
MPI = TRUE/FALSE This enables/disables MPI.
MPICXX = <MPI compiler> This sets the MPI compiler.
CXXSTD = 14 For specifying the C++ standard. We are currently at C++14. Sets the C++ standard - we are currently at C++14.
USE_EB=TRUE Configures Chombo with embedded boundary functionality. This is a requirement.
USE_MF=TRUE Configures Chombo with multifluid functionality. This is a requirement.
USE_MT=TRUE/FALSE Configures Chombo with memory tracking functionality. Not supported with OpenMP.
USE_HDF5 = TRUE/FALSE This enables and disables HDF5 code.
OPENMPCC = TRUE/FALSE Turn on/off OpenMP threading.

MPI

To enable MPI, make sure that MPI is set to true and that the MPICXX compiler is set. For GNU installations, one will usually have MPICXX = mpicxx or MPICXX = mpic++, while for Intel builds one will usually have MPICXX = mpiicpc.

Note

The MPI layer distributes grid patches among processes, i.e. uses domain decomposition.

HDF5

If using HDF5, one must also set the following flags:

HDFINCFLAGS = -I<path to hdf5-serial>/include (for serial HDF5).
HDFLIBFLAGS = -L<path to hdf5-serial>/lib -lhdf5 -lz (for serial HDF5)
HDFMPIINCFLAGS = -I<path to hdf5-parallel>/include (for parallel HDF5)
HDFMPILIBFLAGS = -L<path to hdf5-parallel>/lib -lhdf5 -lz (for parallel HDF5).

Warning

Chombo only supports HDF5 APIs at version 1.10 and below. To use a newer version of HDF5 together with the 1.10 API, add -DH5_USE_110_API to the HDFINC flags.

OpenMP

To turn on OpenMP threading one can set the OPENMPCC to TRUE. When compiled with OpenMP all loops over grid patches uses threading in the form

#pragma omp parallel for schedule(runtime)
for (int mybox = 0; mybox < nbox; mybox++) {

}

Warning

Memory tracking is currently not supported together with threading. When compiling chombo-discharge make sure that memory tracking is turned off (see MainSettings).

Compiler flags

Compiler flags are set through

cxxoptflags = <C++ compiler flags
foptflags = <Fortran compiler flags
syslibflags = <system library flags>

Note that LAPACK and BLAS are requirements in chombo-discharge. Linking to these can often be done using

syslibflag = -llapack -lblas (for GNU compilers)
syslibflag = -mkl=sequential (for Intel compilers)

Pre-defined configuration files

Some commonly used configuration files are found in $DISCHARGE_HOME/Lib/Local. chombo-discharge can be compiled in serial or with MPI, and with or without HDF5. The user need to configure the Chombo makefile to ensure that the chombo-discharge is properly configured. Below, we include brief instructions for compilation on a Linux workstation and for a cluster.

GNU configuration for workstations

Here, we provide a more complete installation example using GNU compilers for a workstation. These steps are intended for users that do not have MPI or HDF5 installed. If you already have installed MPI and/or HDF5, the steps below might require modifications.

Ensure that $DISCHARGE_HOME and $CHOMBO_HOME point to the correct locations:
```
echo $DISCHARGE_HOME
echo $CHOMBO_HOME
```
Install GNU compiler dependencies by
```
sudo apt install csh gfortran g++ libblas-dev liblapack-dev
```
This will install
- LAPACK and BLAS
- GNU compilers for Fortran and C++
To also install OpenMPI and HDF5:
```
sudo apt install libhdf5-dev libhdf5-openmpi-dev openmpi-bin
```
This will install
- OpenMPI
- HDF5, both serial and parallel.
Both serial and parallel HDF5 will be installed, and these are usually found in folders
- /usr/lib/x86_64-linux-gnu/hdf5/serial/ for serial HDF5
- /usr/lib/x86_64-linux-gnu/hdf5/openmpi/ for parallel HDF5 (using OpenMPI).
Before proceeding further, the user need to locate the HDF5 libraries (if building with HDF5).

After installing the dependencies, copy the desired configuration file to $CHOMBO_HOME/mk:

Serial build without HDF5:

cp $DISCHARGE_HOME/Lib/Local/Make.defs.GNU $CHOMBO_HOME/mk/Make.defs.local

Serial build with HDF5:

cp $DISCHARGE_HOME/Lib/Local/Make.defs.HDF5.GNU $CHOMBO_HOME/mk/Make.defs.local

MPI build without HDF5:

cp $DISCHARGE_HOME/Lib/Local/Make.defs.MPI.GNU $CHOMBO_HOME/mk/Make.defs.local

MPI build with HDF5:

cp $DISCHARGE_HOME/Lib/Local/Make.defs.MPI.HDF5.GNU $CHOMBO_HOME/mk/Make.defs.local

Compile the chombo-discharge

cd $DISCHARGE_HOME
make -s -j4 discharge-lib

This will compile the chombo-discharge source code using the configuration settings set by the user. To compile chombo-discharge in 3D, do make -s -j4 DIM=3 discharge-lib. If successful, chombo-discharge libraries will appear in $DISCARGE_HOME/Lib.

Configuration on clusters

To configure chombo-discharge for executation on a cluster, use one of the makefiles supplied in $DISCHARGE_HOME/Lib/Local if it exists for your computer. Alternatively, copy $DISCHARGE_HOME/Lib/Local/Make.defs.local.template to $CHOMBO_HOME/mk/Make.defs.local and set the compilers, optimization flags, and paths to HDF5 library.

On clusters, MPI and HDF5 are usually already installed, but must usually be loaded (e.g. as modules) before compilation.

Configuration files for GitHub

chombo-discharge uses GitHub actions for continuous integration and testing. These tests run on Linux for a selection of GNU and Intel compilers. The configuration files are located in $DISCHARGE_HOME/Lib/Local/GitHub.

Troubleshooting

If the prerequisites are in place, compilation of chombo-discharge is usually straightforward. However, due to dependencies on Chombo and HDF5, compilation can sometimes be an issue. Our experience is that if Chombo compiles, so does chombo-discharge.

If experiencing issues, try cleaning chombo-discharge by

cd $DISCHARGE_HOME
make pristine

Note

Do not hesitate to contact us at GitHub regarding installation issues.

Recommended configurations

Production runs

For production runs, we generally recommend that the user compiles with DEBUG=FALSE and OPT=HIGH. These settings can be set directly in Make.defs.local. Alternatively, they can be included directly on the command line when compiling problems.

Debugging

If you believe that there might be a bug in the code, one can compile with DEBUG=TRUE and OPT=TRUE. This will turn on some assertions throughout Chombo and chombo-discharge.

Common problems

Missing library paths:
On some installations the linker can not find the HDF5 library. To troubleshoot, make sure that the the environment variable LD_LIBRARY_PATH can find the HDF5 libraries:
echo $LD_LIBRARY_PATH
If the path is not included, it can be defined by:
export LD_LIBRARY_PATH=$LD_LIBRARY_PATH:/<path_to_hdf5_installation>/lib
Incomplete perl installations.

Chombo may occasionally complain about incomplete perl modules. These error messages are unrelated to Chombo and chombo-discharge, but the user may need to install additional perl modules before compiling chombo-discharge.

Installation

Obtaining chombo-discharge

Cloning chombo-discharge

Test build

Full configuration

Main settings

MPI

HDF5

OpenMP

Compiler flags

Pre-defined configuration files

GNU configuration for workstations

Configuration on clusters

Configuration files for GitHub

Troubleshooting

Recommended configurations

Production runs

Debugging

Common problems

Obtaining `chombo-discharge`

Cloning `chombo-discharge`