Reorganize ParallelFor source files

Change-Id: Ic4941919e59210b48e447cbb61e539200c8c89df
2026-08-29 16:40:38 +08:00 · 2022-12-19 18:24:54 +03:00
parent ba360ab074
commit 54ad3dd03c
23 changed files with 461 additions and 399 deletions
@@ -0,0 +1,87 @@
+// 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 {
+
+// 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);
+              });
+}
+
+// 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_