Nektar++

Nektar++ is an open-source software framework designed to support the development of high-performance scalable solvers for partial differential equations (PDEs) using the spectral/hp element method.

This package consists of a set of libraries (the framework) and a number of pre-written PDE solvers for a selection of application domains.

The software and User Guide is available for download from http://www.nektar.info/.

User Guide

Detailed information on compiling, installing and using the software is available in the User Guide. This document is available as a pre-compiled PDF from the downloads section of the project website.

Tutorials

A number of tutorials are available, designed to walk the user through the basics of spectral/hp element methods, through the use of individual solvers and performing specific types of calculations.

The tutorials are available from http://doc.nektar.info/tutorials/latest.

Pre-requisites

Nektar++ requires the following software to be installed on the users system:

• CMake
• BLAS/LAPACK

Additional software is also required. This can either be installed system-wide or it can be downloaded and compiled automatically during the build process.

For more detailed information, please see the User Guide.

Compilation

On most UNIX-based systems a default compilation can be performed using the following commands from the top-level of the source tree:

mkdir build
cd build
cmake ..
make

To alter the build configuration (for example, to enable parallel execution support) we recommend using the ccmake command instead of cmake.

For more detailed operating-system specific instructions, please see the User Guide.

Redesign

A minimalist compilation command example is shown below for each available backend:

Serial

cmake .. -DNEKTAR_BUILD_REDESIGN=ON 

AVX2

cmake .. -DNEKTAR_BUILD_REDESIGN=ON \
         -DNEKTAR_ENABLE_SIMD_AVX2=ON 

AVX512

cmake .. -DNEKTAR_BUILD_REDESIGN=ON \
         -DNEKTAR_ENABLE_SIMD_AVX512=ON 

CUDA

cmake .. -DNEKTAR_BUILD_REDESIGN=ON \
         -DNEKTAR_ENABLE_CUDA=ON \
         -DNEKTAR_DEVICE_ARCH=sm_xx \ 

Note:

• For H100, please use sm_xx=sm_90
• For A40, please use sm_xx=sm_86
• For A100, please use sm_xx=sm_80
• For V100, please use sm_xx=sm_70

HIP

cmake .. -DNEKTAR_BUILD_REDESIGN=ON \
         -DNEKTAR_ENABLE_HIP=ON \
         -DCMAKE_CXX_COMPILER=hipcc \
         -DNEKTAR_DEVICE_ARCH=gfxzzz \

Note:

• For MI100, please use gfxzzz=gfx908
• For MI210, please use gfxzzz=gfx90a
• For MI250, please use gfxzzz=gfx90a
• For MI300, please use gfxzzz=gfx942
• For MI325, please use gfxzzz=gfx942

SYCL (Default)

export CL_CONFIG_CPU_FORCE_LOCAL_MEM_SIZE=64K

cmake .. -DNEKTAR_BUILD_REDESIGN=ON \
         -DNEKTAR_ENABLE_SYCL=Default \
         -DCMAKE_CXX_COMPILER="/path-to-intel-compiler/bin/icpx" 

SYCL (CUDA)

cmake .. -DNEKTAR_BUILD_REDESIGN=ON \
         -DNEKTAR_ENABLE_SYCL=CUDA \
         -DNEKTAR_DEVICE_ARCH=sm_xx \ 
         -DCMAKE_CXX_COMPILER="/path-to-intel-compiler/bin/icpx" 

Note:

• For H100, please use sm_xx=sm_90
• For A40, please use sm_xx=sm_86
• For A100, please use sm_xx=sm_80
• For V100, please use sm_xx=sm_70

Installation

The default installation location is in a dist subdirectory of the build directory. This can be changed by setting the CMAKE_INSTALL_PREFIX option using ccmake. To install the compiled libraries, solvers and header files, on UNIX-based systems run:

make install