gz_fft_waves

• This gz package simulates realistic ocean waves generated using FFT.

• This is a modification of the original work done by srmainwaring.

• The goal is to simplify the code base for using only fft based waves and improve realistic reflections.

  

Dependencies

• A working installatin of gazebo sim (harmonic/garden/ionic)

• This package uses FFTW and CGAL, both of which are GPL-3.0 Licensed.

• Ubuntu-22.04 (Jammy)

Installing dependencies :

• Install gazebo harmonic from here.

• Install Colcon for building the package

  sudo apt install python3-pip
  pip install -U colcon-common-extensions

• Install fftw/intel-mkl (for fft) and cgal (for geometric computations) libraries

  sudo apt-get update
  sudo apt-get install libcgal-dev libfftw3-dev
  sudo apt install -y gpg-agent wget
  wget -O- https://apt.repos.intel.com/intel-gpg-keys/GPG-PUB-KEY-INTEL-SW-PRODUCTS.PUB | gpg --dearmor | sudo tee /usr/share/keyrings/oneapi-archive-keyring.gpg > /dev/null
  echo "deb [signed-by=/usr/share/keyrings/oneapi-archive-keyring.gpg] https://apt.repos.intel.com/oneapi all main" | sudo tee /etc/apt/sources.list.d/oneAPI.list
  sudo apt update
  sudo apt install intel-oneapi-mkl
  sudo apt install intel-oneapi-mkl-devel

  • run this onetime command to source the oneapi mkl

    source /opt/intel/oneapi/setvars.sh

Setting up this project

• Create a workspace and clone this repo

  mkdir -p ~/gz_waves_ws/src
  cd ~/gz_waves_ws/src
  git clone https://github.com/ab31mohit/gz_fft_waves.git

• Copy and paste the following lines of code in .bashrc file

  export GZ_VERSION=harmonic
  export GZ_IP=127.0.0.1
  export GZ_DISCOVERY_MULTICST=0
  
  # waves setup
  source ~/gz_waves_ws/install/setup.bash
  
  export GZ_SIM_RESOURCE_PATH=\
  $GZ_SIM_RESOURCE_PATH:\
  ~/gz_waves_ws/src/gz_fft_waves/models:\
  ~/gz_waves_ws/src/gz_fft_waves/worlds
  
  export GZ_SIM_SYSTEM_PLUGIN_PATH=\
  $GZ_SIM_SYSTEM_PLUGIN_PATH:\
  ~/workspace~/gz_waves_ws/install/lib

• Build the package

  cd ~/gz_waves_ws/
  colcon build --symlink-install --merge-install --cmake-args \
  -DCMAKE_BUILD_TYPE=RelWithDebInfo \
  -DBUILD_TESTING=ON \
  -DCMAKE_CXX_STANDARD=17
  source ~/.bashrc

  In case yout system gets stuck during the build process again and again, you can use

  cd ~/gz_waves_ws/
  rm -rf build/ install/ log/
  LDFLAGS="-Wl,--no-keep-memory" MAKEFLAGS="-j1" colcon build \
  --executor sequential \
  --parallel-workers 1 \
  --cmake-args \  
  -DBUILD_TESTING=OFF \  
  -DCMAKE_BUILD_TYPE=RelWithDebInfo \
  -DCMAKE_INTERPROCEDURAL_OPTIMIZATION=OFF
  source ~/.bashrc

• The simply run the ocean.sdf world file directly from the terminal

  gz sim -v4 ocean.sdf

• By default the current code uses Intel MKL oneapi for fft computation.

• For using FFTW3, just interchange the code between these 2 set of files

  LinearRandomFFTWaveSimulationImpl.hh <-----> LinearRandomFFTWaveSimulationImpl_backup.hh

  LinearRandomFFTWaveSimulation.cc <-----> LinearRandomFFTWaveSimulation_backup.cc

• the backup files contain fft computation code using fftw3 library and the current version contains fft computation code using intel mkl oneapi.