Getting Started

Easylambda is a header only libray. The library can be downloaded from the repository (download link). The application that includes the library can be built with parallelism features or without. In non-parallel mode the compilation does not require MPI and boost libraries, making it easier to try and test the library. Follow the instructions given below for quick installation and usage.


  • C++14 compliant compiler.
    • Tested with gcc-6.0, Apple LLVM version 7.0.0 (clang-700.0.72).
  • For parallel build: C++ Boost library 1.58 or later with boost-mpi else boost 1.55 or later header only is sufficient.
  • For parallel build: MPI wrapper compiler (mpic++/mpicxx) and mpirun.

Getting on AWS Elastic

  • Use ami ami-1bad0978 publicly available on Asia-Pacific(Singapore). The ami can be launched for a single node or in a cluster of nodes with starcluster.
  • SSH with username ubuntu.
  • Clone the easyLambda github repository in the home directory and you are ready to compile and run the examples or your applications.


Extract the downloaded zip and place the contents of the include directory in the compiler include path so that it is available to the compiler. If the directory is not added to the include path then the path of the include directory with compiler flag -I can be given while compiling.

  • To install newest gcc on Ubuntu or related distros, check link.
  • For parallel builds: To install boost with mpi follow the link.


There are no linking requirements of ezl library but in parallel build it uses boost::serialization and boost::mpi that need to be linked. Here is how to compile a program in general:

  • For non parallel compilation: g++ file.cpp -Wall -std=c++14 -DNOMPI -O3 -I path_to_ezl_include
  • For parallel compilation: mpic++ file.cpp -Wall -std=c++14 -O3 -I path_to_ezl_include -lboost_mpi -lboost_serialization

Replace path_to_ezl_include with the actual path of ezl include directory in your system. If you have added the contents of include directory to your source tree or global include path then you don’t need to pass -I path_to_ezl_include flag.

For non parallel build -DNOMPI flag is added to the compilation and linking to boost libraries is not required.

To build tests and examples any of the two CMake or Make can be used.

For using CMake follow the following steps:

  • Make a new directory _build or any other name inside the easyLambda main project directory. Go to this directory and run cmake .. for build with parallelism or cmake -DENABLE_MPI=NO .. for non parallel build.
  • Run cmake --build .. Now you can run any test or example that are built. You can use mpirun to run examples if built with parallelism.

For compiling with Make on unix based systems:

  • Unit tests can be compiled with make bin/test and run with ./bin/test.

  • You can compile an example using make with make example fname=name, replace name with the name of the example file for e.g. make example fname=wordcount to compile wordcount example. You can compile all the examples with make examples.


After compiling, the executable can be run with mpirun mpirun -n 4 path_to_exe args… or simply as path_to_exe args….

Using ezl

For all of the core functionality only ezl.hpp is needed to be included in the program. To use generic function objects like ezl::count etc header files from ezl/algorithms/ directory need to be included. The function objects are grouped according to their use case. The algorithms for use with reduce are in reduces.hpp, with filter are in filters.hpp and so on.

There are many examples and demonstrations given in the examples directory, pick an example of your interest to begin with. You can check reference for information on a specific easyLambda call. Learn by example gives a humble introduction to ezl with examples showing many essential features.

For any help please let us know via mail or github issues.