text: // Ceres Solver - A fast non-linear least squares minimizer
  // Copyright 2010, 2011, 2012 Google Inc. All rights reserved.
  // http://code.google.com/p/ceres-solver/
  //
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  // modification, are permitted provided that the following conditions are met:
  //
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  //   this list of conditions and the following disclaimer.
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  //   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
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  //
  // THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
  // AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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  // LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
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  //
  // Author: keir@google.com (Keir Mierle)
  //
  // A evaluate preparer which puts jacobian the evaluated jacobian blocks
  // directly into their final resting place in an overall block sparse matrix.
  // The evaluator takes care to avoid evaluating the jacobian for fixed
  // parameters.
  
  #ifndef CERES_INTERNAL_BLOCK_EVALUATE_PREPARER_H_
  #define CERES_INTERNAL_BLOCK_EVALUATE_PREPARER_H_
  
  #include "ceres/scratch_evaluate_preparer.h"
  
  namespace ceres {
  namespace internal {
  
  class ResidualBlock;
  class SparseMatrix;
  
  class BlockEvaluatePreparer {
   public:
    // Using Init() instead of a constructor allows for allocating this structure
    // with new[]. This is because C++ doesn't allow passing arguments to objects
    // constructed with new[] (as opposed to plain 'new').
    void Init(int const* const* jacobian_layout,
              int max_derivatives_per_residual_block);
  
    // EvaluatePreparer interface
  
    // Point the jacobian blocks directly into the block sparse matrix, if
    // jacobian is non-null. Otherwise, uses an internal per-thread buffer to
    // store the jacobians temporarily.
    void Prepare(const ResidualBlock* residual_block,
                 int residual_block_index,
                 SparseMatrix* jacobian,
                 double** jacobians);
  
   private:
    int const* const* jacobian_layout_;
  
    // For the case that the overall jacobian is not available, but the
    // individual jacobians are requested, use a pass-through scratch evaluate
    // preparer.
    ScratchEvaluatePreparer scratch_evaluate_preparer_;
  };
  
  }  // namespace internal
  }  // namespace ceres
  
  #endif  // CERES_INTERNAL_BLOCK_EVALUATE_PREPARER_H_
  