Squashed 'third_party/ceres/' content from commit e51e9b4

Change-Id: I763587619d57e594d3fa158dc3a7fe0b89a1743b
git-subtree-dir: third_party/ceres
git-subtree-split: e51e9b46f6ca88ab8b2266d0e362771db6d98067
diff --git a/internal/ceres/execution_summary.h b/internal/ceres/execution_summary.h
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+// Ceres Solver - A fast non-linear least squares minimizer
+// Copyright 2015 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.
+//
+// Author: sameeragarwal@google.com (Sameer Agarwal)
+
+#ifndef CERES_INTERNAL_EXECUTION_SUMMARY_H_
+#define CERES_INTERNAL_EXECUTION_SUMMARY_H_
+
+#include <map>
+#include <mutex>
+#include <string>
+
+#include "ceres/internal/port.h"
+#include "ceres/wall_time.h"
+
+namespace ceres {
+namespace internal {
+
+struct CallStatistics {
+  CallStatistics() : time(0.), calls(0) {}
+  double time;
+  int calls;
+};
+
+// Struct used by various objects to report statistics about their
+// execution.
+class ExecutionSummary {
+ public:
+  void IncrementTimeBy(const std::string& name, const double value) {
+    std::lock_guard<std::mutex> l(mutex_);
+    CallStatistics& call_stats = statistics_[name];
+    call_stats.time += value;
+    ++call_stats.calls;
+  }
+
+  const std::map<std::string, CallStatistics>& statistics() const {
+    return statistics_;
+  }
+
+ private:
+  std::mutex mutex_;
+  std::map<std::string, CallStatistics> statistics_;
+};
+
+class ScopedExecutionTimer {
+ public:
+  ScopedExecutionTimer(const std::string& name, ExecutionSummary* summary)
+      : start_time_(WallTimeInSeconds()), name_(name), summary_(summary) {}
+
+  ~ScopedExecutionTimer() {
+    summary_->IncrementTimeBy(name_, WallTimeInSeconds() - start_time_);
+  }
+
+ private:
+  const double start_time_;
+  const std::string name_;
+  ExecutionSummary* summary_;
+};
+
+}  // namespace internal
+}  // namespace ceres
+
+#endif  // CERES_INTERNAL_EXECUTION_SUMMARY_H_