| // Ceres Solver - A fast non-linear least squares minimizer |
| // Copyright 2023 Google Inc. All rights reserved. |
| // http://ceres-solver.org/ |
| // |
| // Redistribution and use in source and binary forms, with or without |
| // modification, are permitted provided that the following conditions are met: |
| // |
| // * Redistributions of source code must retain the above copyright notice, |
| // this list of conditions and the following disclaimer. |
| // * Redistributions in binary form must reproduce the above copyright notice, |
| // this list of conditions and the following disclaimer in the documentation |
| // and/or other materials provided with the distribution. |
| // * Neither the name of Google Inc. nor the names of its contributors may be |
| // used to endorse or promote products derived from this software without |
| // specific prior written permission. |
| // |
| // THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" |
| // AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE |
| // IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE |
| // ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE |
| // LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR |
| // CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF |
| // SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS |
| // INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN |
| // CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) |
| // ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE |
| // POSSIBILITY OF SUCH DAMAGE. |
| // |
| // Authors: vitus@google.com (Michael Vitus), |
| // dmitriy.korchemkin@gmail.com (Dmitriy Korchemkin) |
| |
| #ifndef CERES_INTERNAL_PARALLEL_VECTOR_OPS_H_ |
| #define CERES_INTERNAL_PARALLEL_VECTOR_OPS_H_ |
| |
| #include <mutex> |
| #include <vector> |
| |
| #include "ceres/context_impl.h" |
| #include "ceres/internal/eigen.h" |
| #include "ceres/internal/export.h" |
| #include "ceres/parallel_for.h" |
| |
| namespace ceres::internal { |
| |
| // Lower bound on block size for parallel vector operations. |
| // Operations with vectors of less than kMinBlockSizeParallelVectorOps elements |
| // will be executed in a single thread. |
| constexpr int kMinBlockSizeParallelVectorOps = 1 << 16; |
| // Evaluate vector expression in parallel |
| // Assuming LhsExpression and RhsExpression are some sort of column-vector |
| // expression, assignment lhs = rhs is eavluated over a set of contiguous blocks |
| // in parallel. This is expected to work well in the case of vector-based |
| // expressions (since they typically do not result into temporaries). This |
| // method expects lhs to be size-compatible with rhs |
| template <typename LhsExpression, typename RhsExpression> |
| void ParallelAssign(ContextImpl* context, |
| int num_threads, |
| LhsExpression& lhs, |
| const RhsExpression& rhs) { |
| static_assert(LhsExpression::ColsAtCompileTime == 1); |
| static_assert(RhsExpression::ColsAtCompileTime == 1); |
| CHECK_EQ(lhs.rows(), rhs.rows()); |
| const int num_rows = lhs.rows(); |
| ParallelFor( |
| context, |
| 0, |
| num_rows, |
| num_threads, |
| [&lhs, &rhs](const std::tuple<int, int>& range) { |
| auto [start, end] = range; |
| lhs.segment(start, end - start) = rhs.segment(start, end - start); |
| }, |
| kMinBlockSizeParallelVectorOps); |
| } |
| |
| // Set vector to zero using num_threads |
| template <typename VectorType> |
| void ParallelSetZero(ContextImpl* context, |
| int num_threads, |
| VectorType& vector) { |
| ParallelSetZero(context, num_threads, vector.data(), vector.rows()); |
| } |
| void ParallelSetZero(ContextImpl* context, |
| int num_threads, |
| double* values, |
| int num_values); |
| |
| } // namespace ceres::internal |
| |
| #endif // CERES_INTERNAL_PARALLEL_FOR_H_ |