mirror of
https://github.com/ceres-solver/ceres-solver.git
synced 2026-08-30 00:50:37 +08:00
Sameer Agarwal
92 lines
3.8 KiB
C++
92 lines
3.8 KiB
C++
// 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 "absl/log/check.h"
|
|
#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_
|