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- // -*- mode: c++; coding: utf-8 -*-
- // ra-ra/bench - Stencil-as-view (rank 2).
- // (c) Daniel Llorens - 2016-2023
- // This library is free software; you can redistribute it and/or modify it under
- // the terms of the GNU Lesser General Public License as published by the Free
- // Software Foundation; either version 3 of the License, or (at your option) any
- // later version.
- #include <iostream>
- #include <iomanip>
- #include <random>
- #include "ra/test.hh"
- using std::cout, std::endl, std::flush, ra::TestRecorder, ra::Benchmark;
- using real = double;
- int nx = 1000;
- int ny = 1000;
- int ts = 10;
- auto I = ra::iota(nx-2, 1);
- auto J = ra::iota(ny-2, 1);
- constexpr ra::Small<real, 3, 3> mask = { 0, 1, 0,
- 1, -4, 1,
- 0, 1, 0 };
- #define THEOP template <class A_, class Anext_, class Astencil_> __attribute__((noinline)) \
- auto operator()(A_ & A, Anext_ & Anext, Astencil_ & Astencil)
- // sensitive to RA_DO_CHECK.
- struct f_raw
- {
- THEOP
- {
- for (int i=1; i+1<nx; ++i) {
- for (int j=1; j+1<ny; ++j) {
- Anext(i, j) = -4*A(i, j)
- + A(i+1, j) + A(i, j+1)
- + A(i-1, j) + A(i, j-1);
- }
- }
- std::swap(A.cp, Anext.cp);
- };
- };
- // about as fast as f_raw, but no stencil. Insensitive to RA_DO_CHECK.
- struct f_slices
- {
- THEOP
- {
- Anext(I, J) = -4*A(I, J)
- + A(I+1, J) + A(I, J+1)
- + A(I-1, J) + A(I, J-1);
- std::swap(A.cp, Anext.cp);
- };
- };
- // with stencil, about as fast as f_raw. Sensitive to RA_DO_CHECK.
- struct f_stencil_explicit
- {
- THEOP
- {
- Astencil.cp = A.data();
- Anext(I, J) = map([](auto && A) { return -4*A(1, 1)
- + A(2, 1) + A(1, 2)
- + A(0, 1) + A(1, 0); },
- iter<2>(Astencil));
- std::swap(A.cp, Anext.cp);
- };
- };
- // sum() inside uses run time sizes and 2-dim ply_ravel loop which is slower (2x w/gcc). TODO
- struct f_stencil_arrayop
- {
- THEOP
- {
- Astencil.cp = A.data();
- Anext(I, J) = map([](auto && s) { return sum(s*mask); }, iter<2>(Astencil));
- std::swap(A.cp, Anext.cp);
- };
- };
- // allows traversal order to be chosen between all 6 axes in ply_ravel. 30x slower. TODO
- struct f_sumprod
- {
- THEOP
- {
- Astencil.cp = A.data();
- Anext(I, J) = 0; // TODO miss notation for sum-of-axes without preparing destination...
- Anext(I, J) += map(ra::wrank<2, 2>(std::multiplies<>()), Astencil, mask);
- std::swap(A.cp, Anext.cp);
- };
- };
- // variant of the above, much faster (TODO).
- struct f_sumprod2
- {
- THEOP
- {
- Astencil.cp = A.data();
- Anext(I, J) = 0;
- ply_fixed(map(ra::wrank<0, 2, 2>([](auto && A, auto && B, auto && C) { A += B*C; }), Anext(I, J), Astencil, mask));
- std::swap(A.cp, Anext.cp);
- };
- };
- int main()
- {
- TestRecorder tr(std::cout);
- std::random_device rand;
- real value = rand();
- auto bench = [&](auto & A, auto & Anext, auto & Astencil, auto && ref, auto && tag, auto && f)
- {
- auto bv = Benchmark().repeats(ts).runs(3)
- .once_f([&](auto && repeat)
- {
- Anext = 0.;
- A = value;
- repeat([&]() { f(A, Anext, Astencil); });
- });
- tr.info(std::setw(5), std::fixed, Benchmark::avg(bv)/A.size()/1e-9, " ns [",
- Benchmark::stddev(bv)/A.size()/1e-9 ,"] ", tag)
- .test_rel(ref, A, 1e-10);
- };
- ra::Big<real, 2> Aref;
- tr.section("static rank");
- {
- ra::Big<real, 2> A({nx, ny}, 1.);
- ra::Big<real, 2> Anext({nx, ny}, 0.);
- auto Astencil = stencil(A, 1, 1);
- cout << "Astencil " << format_array(Astencil(0, 0, ra::dots<2>), { .sep0 = "|" }) << endl;
- #define BENCH(ref, op) bench(A, Anext, Astencil, ref, STRINGIZE(op), op {});
- BENCH(A, f_raw);
- Aref = ra::Big<real, 2>(A);
- BENCH(Aref, f_slices);
- BENCH(Aref, f_stencil_explicit);
- BENCH(Aref, f_stencil_arrayop);
- BENCH(Aref, f_sumprod);
- BENCH(Aref, f_sumprod2);
- #undef BENCH
- }
- tr.section("dynamic rank");
- {
- ra::Big<real> B({nx, ny}, 1.);
- ra::Big<real> Bnext({nx, ny}, 0.);
- auto Bstencil = stencil(B, 1, 1);
- cout << "Bstencil " << format_array(Bstencil(0, 0, ra::dots<2>), { .sep0 = "|" }) << endl;
- #define BENCH(ref, op) bench(B, Bnext, Bstencil, ref, STRINGIZE(op), op {});
- // BENCH(Aref, f_raw); // TODO very slow
- BENCH(Aref, f_slices);
- BENCH(Aref, f_stencil_explicit);
- BENCH(Aref, f_stencil_arrayop);
- #undef BENCH
- }
- return tr.summary();
- }
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