This project is a template that demonstrates how to use RAJA and BLT in an application project that uses CMake or Make.

Clone this repository, and all the submodules:

git clone --recursive https://github.com/llnl/raja-project-template

Before we describe how to build the project, it is important to note that it requires out-of-source builds.

To configure and build this project using a default compiler on your system, first create a build subdirectory in the top-level directory of this repo and then run CMake and make:

mkdir build && cd build
cmake ../
make

This will create the binary example.exe in the ./bin directory.

When you run the executable, you will see that it runs a sequential CPU kernel. You can also run an OpenMP multithreaded CPU kernel or a CUDA GPU kernel by enabling those features when you run CMake, specifically, passing the following options to CMake:

• -DENABLE_OPENMP=On will enable the OpenMP back-end (RAJA default: On)
• -DENABLE_CUDA=On will enable the CUDA back-end (RAJA default: Off)

If you want to experiment with RAJA before trying it in your application, you can modify the file ./src/example.cpp, and rebuild the code by running make in the build directory you created earlier.

This project can also be configured to use a pre-installed version of RAJA. This is the recommended method for using RAJA in most applications. Please see the RAJA documentation for details on building and installing RAJA.

Once you have RAJA installed, configure the project by specifying the RAJA location using the CMake option RAJA_DIR:

cmake -DRAJA_DIR=<path to RAJA install directory>/share/raja/cmake ../

Then build as before:

make

If you are building your application against an installed version of RAJA, it's important to make sure that the options you passed to CMake to build RAJA match the options you use to build this project, apart from the one indicated above.

To use RAJA in a project with a make-based build system, you need to add the include directory where RAJA is installed to your compile flags and link against the installed RAJA library. You must also ensure that you add the appropriate flags for any RAJA features you have enabled (e.g. -fopenmp or equivalent if you built RAJA with OpenMP enabled).

For completeness, to compile and link the example in this project using the g++ compiler, you could do the following on the command line:

g++ -I <path to RAJA install directory>/include -std=c++11 -fopenmp ./src/example.cpp -o example.exe <path to RAJA install directory>/lib/libRAJA.a

Since most applications contain more than one source file, you probably want to create a Makefile to use to build your project. Here are the contents of a simple Makefile that builds the example in this project:

CXX=<compiler executable>
CXXFLAGS=-I$(INC_DIR) -std=c++11 -fopenmp

INC_DIR =<path to RAJA install directory>/include
LIB_DIR =<path to RAJA install directory>/include/lib

LIBS=-lRAJA

SRC_DIR=./src
OBJ_DIR=$(SRC_DIR)

OBJ = example.o

$(OBJ_DIR)/%.o: $(SRC_DIR)/%.cpp
     $(CXX) -c -o $@ $< $(CXXFLAGS)

example.exe: $(OBJ_DIR)/$(OBJ)
     $(CXX) -o $@ $^ $(CXXFLAGS) -L $(LIB_DIR) $(LIBS)

.PHONY: clean

clean:
     rm -f $(OBJ_DIR)/*.o example.exe

To try it out, you can copy these lines into a file called Makefile in the top-level project directory and type 'make'. The executable example.exe will be generated in the same directory.

• For more information on RAJA, check out the RAJA tutorial
• For more information on using BLT and CMake, check out the BLT tutorial

If you have questions, comments or ideas, please join the RAJA mailing list on Google Groups here.

RAJA is licensed under the BSD 3-Clause license, (BSD-3-Clause or https://opensource.org/licenses/BSD-3-Clause).

Copyrights and patents in the RAJA project are retained by contributors. No copyright assignment is required to contribute to RAJA.

Unlimited Open Source - BSD 3-clause Distribution LLNL-CODE-689114 OCEC-16-063

Individual files contain SPDX tags instead of the full license text. This enables machine processing of license information based on the SPDX License Identifiers that are available here: https://spdx.org/licenses/

Files that are licensed as BSD 3-Clause contain the following text in the license header:

SPDX-License-Identifier: (BSD-3-Clause)