// Ceres Solver - A fast non-linear least squares minimizer

// Copyright 2015 Google Inc. All rights reserved.

// http://ceres-solver.org/

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// Author: keir@google.com (Keir Mierle)

//

// A scratch evaluate preparer provides temporary storage for the jacobians that

// are created when running user-provided cost functions. The evaluator takes

// care to avoid evaluating the jacobian for fixed parameters.

#ifndef CERES_INTERNAL_SCRATCH_EVALUATE_PREPARER_H_

#define CERES_INTERNAL_SCRATCH_EVALUATE_PREPARER_H_

#include "ceres/internal/scoped_ptr.h"

namespace ceres {

namespace internal {

class Program;

class ResidualBlock;

class SparseMatrix;

class ScratchEvaluatePreparer {

 public:

  // Create num_threads ScratchEvaluatePreparers.

  static ScratchEvaluatePreparer* Create(const Program &program,

                                         int num_threads);

  // EvaluatePreparer interface

  void Init(int max_derivatives_per_residual_block);

  void Prepare(const ResidualBlock* residual_block,

               int residual_block_index,

               SparseMatrix* jacobian,

               double** jacobians);

 private:

  // Scratch space for the jacobians; each jacobian is packed one after another.

  // There is enough scratch to hold all the jacobians for the largest residual.

  scoped_array<double> jacobian_scratch_;

};

}  // namespace internal

}  // namespace ceres

#endif  // CERES_INTERNAL_SCRATCH_EVALUATE_PREPARER_H_