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#include <array>
#include <cstdint>
#include <memory>
#include <chrono>
#include <iostream>
<%
def pop_offset(i):
return i * geometry.volume
%>
void equilibrilize(${float_type}* f_next,
${float_type}* f_prev,
const std::size_t gid)
{
${float_type}* preshifted_f_next = f_next + gid;
${float_type}* preshifted_f_prev = f_prev + gid;
% for i, w_i in enumerate(descriptor.w):
preshifted_f_next[${pop_offset(i)}] = ${w_i}.f;
preshifted_f_prev[${pop_offset(i)}] = ${w_i}.f;
% endfor
}
<%
def neighbor_offset(c_i):
return {
2: lambda: c_i[1]*geometry.size_x + c_i[0],
3: lambda: c_i[2]*geometry.size_x*geometry.size_y + c_i[1]*geometry.size_x + c_i[0]
}.get(descriptor.d)()
%>
void collide_and_stream( ${float_type}* f_next,
const ${float_type}* f_prev,
const int* material,
const std::size_t gid)
{
const int m = material[gid];
if ( m == 0 ) {
return;
}
${float_type}* preshifted_f_next = f_next + gid;
const ${float_type}* preshifted_f_prev = f_prev + gid;
% for i, c_i in enumerate(descriptor.c):
const ${float_type} f_curr_${i} = preshifted_f_prev[${pop_offset(i) + neighbor_offset(-c_i)}];
% endfor
% for i, expr in enumerate(moments_subexpr):
const ${float_type} ${expr[0]} = ${ccode(expr[1])};
% endfor
% for i, expr in enumerate(moments_assignment):
${float_type} ${ccode(expr)}
% endfor
% for i, expr in enumerate(collide_subexpr):
const ${float_type} ${expr[0]} = ${ccode(expr[1])};
% endfor
% for i, expr in enumerate(collide_assignment):
preshifted_f_next[${pop_offset(i)}] = ${ccode(expr.rhs)};
% endfor
}
int main()
{
auto f_a = std::make_unique<${float_type}[]>(${geometry.volume*descriptor.q});
auto f_b = std::make_unique<${float_type}[]>(${geometry.volume*descriptor.q});
auto material = std::make_unique<int[]>(${geometry.volume});
${float_type}* f_prev = f_a.get();
${float_type}* f_next = f_b.get();
for (int iX = 0; iX < ${geometry.size_x}; ++iX) {
for (int iY = 0; iY < ${geometry.size_y}; ++iY) {
for (int iZ = 0; iZ < ${geometry.size_z}; ++iZ) {
if (iX == 0 || iY == 0 || iZ == 0 || iX == ${geometry.size_x-1} || iY == ${geometry.size_y-1} || iZ == ${geometry.size_z-1}) {
material[iZ*${geometry.size_x*geometry.size_y} + iY*${geometry.size_x} + iX] = 0;
} else {
material[iZ*${geometry.size_x*geometry.size_y} + iY*${geometry.size_x} + iX] = 1;
}
}
}
}
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 < ${steps}; ++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();
}
for (std::size_t iCell = 0; iCell < ${geometry.volume}; ++iCell) {
collide_and_stream(f_next, f_prev, material.get(), iCell);
}
}
auto duration = std::chrono::duration_cast<std::chrono::duration<double>>(
std::chrono::high_resolution_clock::now() - start);
std::cout << "MLUPS: " << ${steps*geometry.volume}/(1e6*duration.count()) << std::endl;
return 0;
}
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