Squashed 'third_party/ceres/' content from commit e51e9b4

Change-Id: I763587619d57e594d3fa158dc3a7fe0b89a1743b
git-subtree-dir: third_party/ceres
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diff --git a/include/ceres/internal/variadic_evaluate.h b/include/ceres/internal/variadic_evaluate.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)
+//         mierle@gmail.com (Keir Mierle)
+//         jodebo_beck@gmx.de (Johannes Beck)
+
+#ifndef CERES_PUBLIC_INTERNAL_VARIADIC_EVALUATE_H_
+#define CERES_PUBLIC_INTERNAL_VARIADIC_EVALUATE_H_
+
+#include <stddef.h>
+
+#include <type_traits>
+
+#include "ceres/cost_function.h"
+#include "ceres/internal/parameter_dims.h"
+
+namespace ceres {
+namespace internal {
+
+// For fixed size cost functors
+template <typename Functor, typename T, int... Indices>
+inline bool VariadicEvaluateImpl(const Functor& functor, T const* const* input,
+                                 T* output, std::false_type /*is_dynamic*/,
+                                 integer_sequence<int, Indices...>) {
+  static_assert(sizeof...(Indices),
+                "Invalid number of parameter blocks. At least one parameter "
+                "block must be specified.");
+  return functor(input[Indices]..., output);
+}
+
+// For dynamic sized cost functors
+template <typename Functor, typename T>
+inline bool VariadicEvaluateImpl(const Functor& functor, T const* const* input,
+                                 T* output, std::true_type /*is_dynamic*/,
+                                 integer_sequence<int>) {
+  return functor(input, output);
+}
+
+// For ceres cost functors (not ceres::CostFunction)
+template <typename ParameterDims, typename Functor, typename T>
+inline bool VariadicEvaluateImpl(const Functor& functor, T const* const* input,
+                                 T* output, const void* /* NOT USED */) {
+  using ParameterBlockIndices =
+      make_integer_sequence<int, ParameterDims::kNumParameterBlocks>;
+  using IsDynamic = std::integral_constant<bool, ParameterDims::kIsDynamic>;
+  return VariadicEvaluateImpl(functor, input, output, IsDynamic(),
+                              ParameterBlockIndices());
+}
+
+// For ceres::CostFunction
+template <typename ParameterDims, typename Functor, typename T>
+inline bool VariadicEvaluateImpl(const Functor& functor, T const* const* input,
+                                 T* output,
+                                 const CostFunction* /* NOT USED */) {
+  return functor.Evaluate(input, output, nullptr);
+}
+
+// Variadic evaluate is a helper function to evaluate ceres cost function or
+// functors using an input, output and the parameter dimensions. There are
+// several ways different possibilities:
+// 1) If the passed functor is a 'ceres::CostFunction' its evaluate method is
+// called.
+// 2) If the functor is not a 'ceres::CostFunction' and the specified parameter
+// dims is dynamic, the functor must have the following signature
+// 'bool(T const* const* input, T* output)'.
+// 3) If the functor is not a 'ceres::CostFunction' and the specified parameter
+// dims is not dynamic, the input is expanded by using the number of parameter
+// blocks. The signature of the functor must have the following signature
+// 'bool()(const T* i_1, const T* i_2, ... const T* i_n, T* output)'.
+template <typename ParameterDims, typename Functor, typename T>
+inline bool VariadicEvaluate(const Functor& functor, T const* const* input,
+                             T* output) {
+  return VariadicEvaluateImpl<ParameterDims>(functor, input, output, &functor);
+}
+
+}  // namespace internal
+}  // namespace ceres
+
+#endif  // CERES_PUBLIC_INTERNAL_VARIADIC_EVALUATE_H_