internal/ceres/parallel_for.h

// Ceres Solver - A fast non-linear least squares minimizer
// Copyright 2018 Google Inc. All rights reserved.
// http://ceres-solver.org/
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// Author: vitus@google.com (Michael Vitus)

#ifndef CERES_INTERNAL_PARALLEL_FOR_
#define CERES_INTERNAL_PARALLEL_FOR_

#include <functional>

#include "ceres/context_impl.h"

namespace ceres {
namespace internal {

// Returns the maximum number of threads supported by the threading backend
// Ceres was compiled with.
int MaxNumThreadsAvailable();

// Execute the function for every element in the range [start, end) with at most
// num_threads. It will execute all the work on the calling thread if
// num_threads is 1.
void ParallelFor(ContextImpl* context,
                 int start,
                 int end,
                 int num_threads,
                 const std::function<void(int)>& function);

// Execute the function for every element in the range [start, end) with at most
// num_threads. It will execute all the work on the calling thread if
// num_threads is 1.  Each invocation of function() will be passed a thread_id
// in [0, num_threads) that is guaranteed to be distinct from the value passed
// to any concurrent execution of function().
void ParallelFor(ContextImpl* context,
                 int start,
                 int end,
                 int num_threads,
                 const std::function<void(int thread_id, int i)>& function);
}  // namespace internal
}  // namespace ceres

#endif  // CERES_INTERNAL_PARALLEL_FOR_H_