From d540b701836dbcdef727947f52a0ca01430968a6 Mon Sep 17 00:00:00 2001
From: Adrian Kummerlaender
Date: Wed, 30 Oct 2019 19:45:39 +0100
Subject: Rename folder, add basic README.md
---
lid_driven_cavity/cpp/CMakeLists.txt | 44 +++++++++
lid_driven_cavity/cpp/README.md | 18 ++++
lid_driven_cavity/cpp/config.py | 13 +++
lid_driven_cavity/cpp/generate.py | 40 ++++++++
lid_driven_cavity/cpp/ldc.cpp.mako | 176 +++++++++++++++++++++++++++++++++++
5 files changed, 291 insertions(+)
create mode 100644 lid_driven_cavity/cpp/CMakeLists.txt
create mode 100644 lid_driven_cavity/cpp/README.md
create mode 100644 lid_driven_cavity/cpp/config.py
create mode 100755 lid_driven_cavity/cpp/generate.py
create mode 100644 lid_driven_cavity/cpp/ldc.cpp.mako
(limited to 'lid_driven_cavity/cpp')
diff --git a/lid_driven_cavity/cpp/CMakeLists.txt b/lid_driven_cavity/cpp/CMakeLists.txt
new file mode 100644
index 0000000..5b5fb90
--- /dev/null
+++ b/lid_driven_cavity/cpp/CMakeLists.txt
@@ -0,0 +1,44 @@
+cmake_minimum_required(VERSION 3.10)
+project(ldc LANGUAGES CXX)
+
+if(NOT CMAKE_BUILD_TYPE)
+ set(CMAKE_BUILD_TYPE Release)
+endif()
+
+set(CMAKE_CXX_FLAGS_RELEASE "-O3")
+
+add_custom_command(
+ OUTPUT
+ kernel.h
+ ldc.cpp
+ COMMAND
+ ${CMAKE_CURRENT_SOURCE_DIR}/generate.py --output ${CMAKE_CURRENT_BINARY_DIR}
+ WORKING_DIRECTORY
+ ${CMAKE_CURRENT_SOURCE_DIR}
+ DEPENDS
+ generate.py config.py ldc.cpp.mako
+)
+
+include_directories(
+ ${CMAKE_BINARY_DIR}
+)
+
+add_executable(
+ ldc
+ ${CMAKE_CURRENT_BINARY_DIR}/ldc.cpp
+)
+
+target_compile_features(
+ ldc
+ PUBLIC
+ cxx_std_17
+)
+
+find_package(OpenMP)
+if(OpenMP_CXX_FOUND)
+ target_link_libraries(
+ ldc
+ PUBLIC
+ OpenMP::OpenMP_CXX
+ )
+endif()
diff --git a/lid_driven_cavity/cpp/README.md b/lid_driven_cavity/cpp/README.md
new file mode 100644
index 0000000..8e84c83
--- /dev/null
+++ b/lid_driven_cavity/cpp/README.md
@@ -0,0 +1,18 @@
+# Lid driven cavity
+
+This example models the common lid driven cavity example.
+Note that the actual optimized C++ implementation is generated using the _boltzgen_ library.
+
+See `config.py` for various configuration options. Both 2D and 3D are supported.
+
+## Build instructions
+
+```
+mkdir build
+cd build
+cmake ..
+make
+./ldc
+```
+
+This should result in some summarizing CLI output in addition to a `test.vtk` file for visualization in Paraview.
diff --git a/lid_driven_cavity/cpp/config.py b/lid_driven_cavity/cpp/config.py
new file mode 100644
index 0000000..3ed8bd5
--- /dev/null
+++ b/lid_driven_cavity/cpp/config.py
@@ -0,0 +1,13 @@
+from boltzgen.lbm.model import *
+from boltzgen import Geometry
+
+descriptor = D2Q9
+geometry = Geometry(512, 512)
+tau = 0.52
+precision = 'single'
+
+## 3D LDC
+#descriptor = D3Q19
+#geometry = Geometry(64, 64, 64)
+#tau = 0.52
+#precision = 'single'
diff --git a/lid_driven_cavity/cpp/generate.py b/lid_driven_cavity/cpp/generate.py
new file mode 100755
index 0000000..4222e98
--- /dev/null
+++ b/lid_driven_cavity/cpp/generate.py
@@ -0,0 +1,40 @@
+#!/usr/bin/env python
+
+import argparse
+
+from boltzgen import LBM, Generator, Geometry
+from boltzgen.lbm.model import D2Q9
+
+import config
+
+argparser = argparse.ArgumentParser(
+ description = 'Generate a C++ implementation of a lid driven cavity simulation using LBM')
+argparser.add_argument(
+ '--output', required = False, help = 'Target directory for the generated sources')
+
+args = argparser.parse_args()
+
+lbm = LBM(config.descriptor)
+generator = Generator(
+ descriptor = config.descriptor,
+ moments = lbm.moments(),
+ collision = lbm.bgk(f_eq = lbm.equilibrium(), tau = config.tau),
+ target = 'cpp',
+ precision = config.precision,
+ index = 'XYZ',
+ layout = 'AOS')
+
+if args.output is None:
+ args.output = '.'
+
+functions = ['collide_and_stream', 'equilibrilize', 'collect_moments', 'momenta_boundary']
+
+with open('%s/kernel.h' % args.output, 'w') as kernel:
+ kernel.write(generator.kernel(config.geometry, functions))
+
+ldc_src = ''
+with open('ldc.cpp.mako', 'r') as template:
+ ldc_src = template.read()
+
+with open('%s/ldc.cpp' % args.output, 'w') as app:
+ app.write(generator.custom(config.geometry, ldc_src))
diff --git a/lid_driven_cavity/cpp/ldc.cpp.mako b/lid_driven_cavity/cpp/ldc.cpp.mako
new file mode 100644
index 0000000..5d480de
--- /dev/null
+++ b/lid_driven_cavity/cpp/ldc.cpp.mako
@@ -0,0 +1,176 @@
+#include <cstdint>
+#include <memory>
+#include <vector>
+#include <chrono>
+#include <iostream>
+#include <fstream>
+
+#include "kernel.h"
+
+void collect_moments_to_vtk(const std::string& path, ${float_type}* f) {
+ std::ofstream fout;
+ fout.open(path.c_str());
+
+ fout << "# vtk DataFile Version 3.0\n";
+ fout << "lbm_output\n";
+ fout << "ASCII\n";
+ fout << "DATASET RECTILINEAR_GRID\n";
+% if descriptor.d == 2:
+ fout << "DIMENSIONS " << ${geometry.size_x-2} << " " << ${geometry.size_y-2} << " 1" << "\n";
+% else:
+ fout << "DIMENSIONS " << ${geometry.size_x-2} << " " << ${geometry.size_y-2} << " " << ${geometry.size_z-2} << "\n";
+% endif
+
+ fout << "X_COORDINATES " << ${geometry.size_x-2} << " float\n";
+ for( std::size_t x = 1; x < ${geometry.size_x-1}; ++x ) {
+ fout << x << " ";
+ }
+
+ fout << "\nY_COORDINATES " << ${geometry.size_y-2} << " float\n";
+ for( std::size_t y = 1; y < ${geometry.size_y-1}; ++y ) {
+ fout << y << " ";
+ }
+
+% if descriptor.d == 2:
+ fout << "\nZ_COORDINATES " << 1 << " float\n";
+ fout << 0 << "\n";
+ fout << "POINT_DATA " << ${(geometry.size_x-2) * (geometry.size_y-2)} << "\n";
+% else:
+ fout << "\nZ_COORDINATES " << ${geometry.size_z-2} << " float\n";
+ for( std::size_t z = 1; z < ${geometry.size_z-1}; ++z ) {
+ fout << z << " ";
+ }
+ fout << "\nPOINT_DATA " << ${(geometry.size_x-2) * (geometry.size_y-2) * (geometry.size_z-2)} << "\n";
+% endif
+
+ ${float_type} rho;
+ ${float_type} u[${descriptor.d}];
+
+ fout << "VECTORS velocity float\n";
+% if descriptor.d == 2:
+ for ( std::size_t y = 1; y < ${geometry.size_y-1}; ++y ) {
+ for ( std::size_t x = 1; x < ${geometry.size_x-1}; ++x ) {
+ collect_moments(f, x*${geometry.size_y}+y, rho, u);
+ fout << u[0] << " " << u[1] << " 0\n";
+ }
+ }
+% else:
+ for ( std::size_t z = 1; z < ${geometry.size_z-1}; ++z ) {
+ for ( std::size_t y = 1; y < ${geometry.size_y-1}; ++y ) {
+ for ( std::size_t x = 1; x < ${geometry.size_x-1}; ++x ) {
+ collect_moments(f, x*${geometry.size_y*geometry.size_z}+y*${geometry.size_z}+z, rho, u);
+ fout << u[0] << " " << u[1] << " " << u[2] << "\n";
+ }
+ }
+ }
+% endif
+
+ fout << "SCALARS density float 1\n";
+ fout << "LOOKUP_TABLE default\n";
+% if descriptor.d == 2:
+ for ( std::size_t y = 1; y < ${geometry.size_y-1}; ++y ) {
+ for ( std::size_t x = 1; x < ${geometry.size_x-1}; ++x ) {
+ collect_moments(f, x*${geometry.size_y}+y, rho, u);
+ fout << rho << "\n";
+ }
+ }
+% else:
+ for ( std::size_t z = 1; z < ${geometry.size_z-1}; ++z ) {
+ for ( std::size_t y = 1; y < ${geometry.size_y-1}; ++y ) {
+ for ( std::size_t x = 1; x < ${geometry.size_x-1}; ++x ) {
+ collect_moments(f, x*${geometry.size_y*geometry.size_z}+y*${geometry.size_z}+z, rho, u);
+ fout << rho << "\n";
+ }
+ }
+ }
+% endif
+
+ fout.close();
+}
+
+void simulate(std::size_t nStep)
+{
+ auto f_a = std::make_unique<${float_type}[]>(${geometry.volume*descriptor.q});
+ auto f_b = std::make_unique<${float_type}[]>(${geometry.volume*descriptor.q});
+
+ ${float_type}* f_prev = f_a.get();
+ ${float_type}* f_next = f_b.get();
+
+ std::vector<std::size_t> bulk;
+ std::vector<std::size_t> lid_bc;
+ std::vector<std::size_t> box_bc;
+
+ for (int iX = 1; iX < ${geometry.size_x-1}; ++iX) {
+ for (int iY = 1; iY < ${geometry.size_y-1}; ++iY) {
+% if descriptor.d == 2:
+ const std::size_t iCell = iX*${geometry.size_y} + iY;
+ if (iY == ${geometry.size_y-2}) {
+ lid_bc.emplace_back(iCell);
+ } else if (iX == 1 || iX == ${geometry.size_x-2} || iY == 1) {
+ box_bc.emplace_back(iCell);
+ } else {
+ bulk.emplace_back(iCell);
+ }
+% elif descriptor.d == 3:
+ for (int iZ = 0; iZ < ${geometry.size_z}; ++iZ) {
+ const std::size_t iCell = iX*${geometry.size_y*geometry.size_z} + iY*${geometry.size_z} + iZ;
+ if (iZ == ${geometry.size_z-2}) {
+ lid_bc.emplace_back(iCell);
+ } else if (iX == 1 || iX == ${geometry.size_x-2} || iY == 1 || iY == ${geometry.size_y-2} || iZ == 1) {
+ box_bc.emplace_back(iCell);
+ } else {
+ bulk.emplace_back(iCell);
+ }
+ }
+% endif
+ }
+ }
+
+ std::cout << "#bulk : " << bulk.size() << std::endl;
+ std::cout << "#lid : " << lid_bc.size() << std::endl;
+ std::cout << "#wall : " << box_bc.size() << std::endl;
+ std::cout << "#steps : " << nStep << std::endl;
+ std::cout << std::endl;
+
+ for (std::size_t iCell = 0; iCell < ${geometry.volume}; ++iCell) {
+ equilibrilize(f_prev, f_next, iCell);
+ }
+
+ const auto start = std::chrono::high_resolution_clock::now();
+
+ for (std::size_t iStep = 0; iStep < nStep; ++iStep) {
+ if (iStep % 2 == 0) {
+ f_next = f_a.get();
+ f_prev = f_b.get();
+ } else {
+ f_next = f_b.get();
+ f_prev = f_a.get();
+ }
+
+#pragma omp parallel for
+ for (std::size_t i = 0; i < bulk.size(); ++i) {
+ collide_and_stream(f_next, f_prev, bulk[i]);
+ }
+ ${float_type} u[${descriptor.d}] { 0. };
+#pragma omp parallel for
+ for (std::size_t i = 0; i < box_bc.size(); ++i) {
+ velocity_momenta_boundary(f_next, f_prev, box_bc[i], u);
+ }
+ u[0] = 0.05;
+#pragma omp parallel for
+ for (std::size_t i = 0; i < lid_bc.size(); ++i) {
+ velocity_momenta_boundary(f_next, f_prev, lid_bc[i], u);
+ }
+ }
+
+ auto duration = std::chrono::duration_cast<std::chrono::duration<double>>(
+ std::chrono::high_resolution_clock::now() - start);
+
+ std::cout << "MLUPS : " << nStep*${geometry.volume}/(1e6*duration.count()) << std::endl;
+
+ collect_moments_to_vtk("test.vtk", f_next);
+}
+
+int main() {
+ simulate(10000);
+}
--
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