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diff --git a/extern/ceres/internal/ceres/block_evaluate_preparer.cc b/extern/ceres/internal/ceres/block_evaluate_preparer.cc
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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: keir@google.com (Keir Mierle)
+
+#include "ceres/block_evaluate_preparer.h"
+
+#include <vector>
+#include "ceres/block_sparse_matrix.h"
+#include "ceres/casts.h"
+#include "ceres/parameter_block.h"
+#include "ceres/residual_block.h"
+#include "ceres/sparse_matrix.h"
+
+namespace ceres {
+namespace internal {
+
+void BlockEvaluatePreparer::Init(int const* const* jacobian_layout,
+                                 int max_derivatives_per_residual_block) {
+  jacobian_layout_ = jacobian_layout;
+  scratch_evaluate_preparer_.Init(max_derivatives_per_residual_block);
+}
+
+// Point the jacobian blocks directly into the block sparse matrix.
+void BlockEvaluatePreparer::Prepare(const ResidualBlock* residual_block,
+                                    int residual_block_index,
+                                    SparseMatrix* jacobian,
+                                    double** jacobians) {
+  // If the overall jacobian is not available, use the scratch space.
+  if (jacobian == NULL) {
+    scratch_evaluate_preparer_.Prepare(residual_block,
+                                       residual_block_index,
+                                       jacobian,
+                                       jacobians);
+    return;
+  }
+
+  double* jacobian_values =
+      down_cast<BlockSparseMatrix*>(jacobian)->mutable_values();
+
+  const int* jacobian_block_offset = jacobian_layout_[residual_block_index];
+  const int num_parameter_blocks = residual_block->NumParameterBlocks();
+  for (int j = 0; j < num_parameter_blocks; ++j) {
+    if (!residual_block->parameter_blocks()[j]->IsConstant()) {
+      jacobians[j] = jacobian_values + *jacobian_block_offset;
+
+      // The jacobian_block_offset can't be indexed with 'j' since the code
+      // that creates the layout strips out any blocks for inactive
+      // parameters. Instead, bump the pointer for active parameters only.
+      jacobian_block_offset++;
+    } else {
+      jacobians[j] = NULL;
+    }
+  }
+}
+
+}  // namespace internal
+}  // namespace ceres