// Ceres Solver - A fast non-linear least squares minimizer
// Copyright 2017 Google Inc. All rights reserved.
// http://ceres-solver.org/
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// Author: sameeragarwal@google.com (Sameer Agarwal)
//
// A solver for sparse linear least squares problem based on solving
// the normal equations via a sparse cholesky factorization.

#ifndef CERES_INTERNAL_DYNAMIC_SPARSE_NORMAL_CHOLESKY_SOLVER_H_
#define CERES_INTERNAL_DYNAMIC_SPARSE_NORMAL_CHOLESKY_SOLVER_H_

// This include must come before any #ifndef check on Ceres compile options.
#include "ceres/internal/port.h"

#include "ceres/internal/macros.h"
#include "ceres/linear_solver.h"

namespace ceres {
namespace internal {

class CompressedRowSparseMatrix;

// A variant of SparseNormalCholeskySolver in the case where matrix
// sparsity is not constant across calls to Solve. This means that
// there is no benefit to symbolically factorizing the matrix and
// caching this factorization.
class DynamicSparseNormalCholeskySolver
    : public CompressedRowSparseMatrixSolver {
 public:
  explicit DynamicSparseNormalCholeskySolver(
      const LinearSolver::Options& options);
  virtual ~DynamicSparseNormalCholeskySolver() {}

 private:
  virtual LinearSolver::Summary SolveImpl(
      CompressedRowSparseMatrix* A,
      const double* b,
      const LinearSolver::PerSolveOptions& options,
      double* x);

  LinearSolver::Summary SolveImplUsingSuiteSparse(
      CompressedRowSparseMatrix* A,
      double* rhs_and_solution);

  LinearSolver::Summary SolveImplUsingCXSparse(
      CompressedRowSparseMatrix* A,
      double* rhs_and_solution);

  LinearSolver::Summary SolveImplUsingEigen(
      CompressedRowSparseMatrix* A,
      double* rhs_and_solution);

  const LinearSolver::Options options_;
  CERES_DISALLOW_COPY_AND_ASSIGN(DynamicSparseNormalCholeskySolver);
};

}  // namespace internal
}  // namespace ceres

#endif  // CERES_INTERNAL_DYNAMIC_SPARSE_NORMAL_CHOLESKY_SOLVER_H_