PAnEn: Parallel Analog Ensemble

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About Parallel Analog Ensemble

Parallel Analog Ensemble (PAnEn) is a parallel implementation for Analog Ensemble (AnEn) which generates uncertainty information for a deterministic predictive model. Analogs are generated by using the predictive model and the corresponding historical observations. An introduction to Analog Ensemble technique can be found in this post. It has been successfully applied to forecasts of several weather variables, for example, short-term temperature and wind speed predictions. Publications can be found in the references.

PAnEn is developed by Geoinformatics and Earth Observation Laboratory at Penn State University. This website contains information for installing and using the PAnEn programs and packages. R and C++ documentation can be found on the right. Posts for various topics can also be found there, and are organized by tags. If you have any questions, please open an issue here.

This package contains several libraries and applications:

Requirement and Dependencies

A list of requirement and dependency is provided below. Note that you don’t necessarily have to install them all because some of them can be automatically installed or you simply are not installing some components of the program. For example, you won’t need R if you only need the C++ program; and you won’t need Boost C++ and NetCDF-C if you are only installing the R package RAnEn.

Dependency Description
CMake Required for the C++ program.
GCC/Clang Required for the C++ program.
NetCDF-C Optional for the C++ program. If it is not found, the project will try to build it.
Boost C++ Optional for the C++ program. It is recommended to let the project build it for the C++ program.
CppUnit Required for the C++ program when building tests.
R Required for the R library.
OpenMP Optional for both R and C++.


C++ PAnEn

First, make sure you have already installed the dependencies. Typically GNU compilers with a version later than 4.9, netCDF-C, and CMake is required. If you are using MacOS, you probably need to install GNU compilers in order to have OpenMP multithreading available.

Then, please clone or download the repository here and create a build/ folder under the repository directory.

git clone
cd AnalogsEnsemble
mkdir build
cd build
cmake ..

# If you would like to change the default compiler, specify the compilers like this
# CC=[full path to CC] CXX=[full path to CXX] cmake ..

# You can scoll down to explore more parameters for cmake
# cmake -DCMAKE_INSTALL_PREFIX=/some/folder/ -DBOOST_TYPE=SYSTEM [other parameters] ..

Read the output messages and make sure there are no errors. If you would like to change parameters for cmake, please delete all files in build/ folder and rerun the cmake command.

Then, please compile the programs and the libraries.


# Or if you are using UNIX system, use the flag -j[number of cores] to parallelize the make process
make -j4

# Build document if needed. The /html and the /man folders will be in your build directory
# make document

# If you want to install the program to your machine
# make install

After the compilation, the programs and libraries should be in the folder AnalogsEnsemble/output. Please cd into the binary folder [Where your repository folder is]/AnalogsEnsemble/output/bin/ and run the following command to see help messages.

# Analog Ensemble program --- Analog Generator
# Available options:
#  -h [ --help ]             Print help information for options.
#  -c [ --config ] arg       Set the configuration file path. Command line 
#                            options overwrite options in configuration file. 
# ... [subsequent texts ignored]

If you want to clean up the folder, please do the following.

make clean


The command is the same for RAnEn installation and update.

Generally, R version should be later than or equal to 3.3.0. And the following R packages are needed:

If your operating system is Windows, please also install Rtools.

One-Line Solution

The following R command installs the latest version of RAnEn.

# Read more if OpenMP is not supported
install.packages("", repos = NULL)
Solution for a Specific Version

If you want to install a specific version of RAnEn, you can go to the release folder, copy the full name of the tarball file, replace the following part [tarball name] (including the square bracket) with it, and run the command in R.

# Read more if OpenMP is not supported
install.packages("[tarball name]", repos = NULL)

If Openmp multithreading is not supported, or if you simply want to use a different compiler, please create a Makevars file under ~/.R, with the following content.

CXX1X=[C++11 compiler]

# required on Mac OS
CXX11=[C++11 compiler]

CMake Tunable Parameters Look-up

Parameter Explanation Default
CC The C compiler to use. [System dependent]
CXX The C++ compiler to use. [System dependent]
INSTALL_RAnEn Build and install the RAnEn library. OFF
BOOST_TYPE BUILD for building Boost library; SYSTEM for using the library on the system. BUILD
NETCDF_CXX4_TYPE BUILD for building Netcdf C++4 library; SYSTEM for using the library on the system. BUILD
CPPUNIT_TYPE BUILD for building CppUnit library; SYSTEM for using the CppUnit library from the system. BUILD
CMAKE_BUILD_TYPE Release for release mode; Debug for debug mode. Release
CMAKE_PREFIX_PATH Which folder(s) should cmake search for packages besides the default. Paths are surrounded by double quotes and separated with semicolons. [Empty]
CMAKE_INSTALL_PREFIX The installation directory. [System dependent]
BUILD_NETCDF Build NetCDF library regardless of its existence. OFF
USE_NCCONFIG Use the nc_config program if found. This might cause problems sometimes if not properly setup. ON
BUILD_HDF5 Build HDF5 library regardless of its existence. OFF
VERBOSE Print detailed messages during the compiling process. OFF
CODE_PROFILING Print time profiling information. OFF
ENABLE_MPI Build the MPI version of the CAnEnIO library for parallel I/O. But this is still underdevelopment. OFF
BUILD_GRIBCONVERTER Build the GRIB Converter utility. Eccodes library required. OFF


Known Issues

Please see known issues in this post. If you could not find solutions to your issue, please submit an issue. Thank you.


We appreciate collaborations and feedbacks from users. Please contact maintainer Weiming Hu through or submit tickets if you have any problems.

Thank you!

# "`-''-/").___..--''"`-._
#  (`6_ 6  )   `-.  (     ).`-.__.`)   WE ARE ...
#  (_Y_.)'  ._   )  `._ `. ``-..-'    PENN STATE!
#    _ ..`--'_..-_/  /--'_.' ,'
#  (il),-''  (li),'  ((!.-'
# Authors: 
#     Weiming Hu <>
#     Guido Cervone <>
# Contributors: 
#     Laura Clemente-Harding <>
#     Martina Calovi <>
#     Luca Delle Monache
# Geoinformatics and Earth Observation Laboratory (
# Department of Geography and Institute for CyberScience
# The Pennsylvania State University