// 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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// Author: sameeragarwal@google.com (Sameer Agarwal)
//
// Base classes for access to an linear operator.

#ifndef CERES_INTERNAL_LINEAR_OPERATOR_H_
#define CERES_INTERNAL_LINEAR_OPERATOR_H_

#include "ceres/types.h"

namespace ceres {
namespace internal {

// This is an abstract base class for linear operators. It supports
// access to size information and left and right multiply operators.
class LinearOperator {
 public:
  virtual ~LinearOperator();

  // y = y + Ax;
  virtual void RightMultiply(const double* x, double* y) const = 0;
  // y = y + A'x;
  virtual void LeftMultiply(const double* x, double* y) const = 0;

  virtual int num_rows() const = 0;
  virtual int num_cols() const = 0;
};

}  // namespace internal
}  // namespace ceres

#endif  // CERES_INTERNAL_LINEAR_OPERATOR_H_