// 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: sameeragarwal@google.com (Sameer Agarwal)

#include "ceres/gradient_problem.h"

#include "ceres/local_parameterization.h"

#include "glog/logging.h"

namespace ceres {

GradientProblem::GradientProblem(FirstOrderFunction* function)

    : function_(function),

      parameterization_(

          new IdentityParameterization(function_->NumParameters())),

      scratch_(new double[function_->NumParameters()]) {

}

GradientProblem::GradientProblem(FirstOrderFunction* function,

                                 LocalParameterization* parameterization)

      : function_(function),

        parameterization_(parameterization),

        scratch_(new double[function_->NumParameters()]) {

  CHECK_EQ(function_->NumParameters(), parameterization_->GlobalSize());

}

int GradientProblem::NumParameters() const {

  return function_->NumParameters();

}

int GradientProblem::NumLocalParameters() const {

  return parameterization_->LocalSize();

}

bool GradientProblem::Evaluate(const double* parameters,

                               double* cost,

                               double* gradient) const {

  if (gradient == NULL) {

    return function_->Evaluate(parameters, cost, NULL);

  }

  return (function_->Evaluate(parameters, cost, scratch_.get()) &&

          parameterization_->MultiplyByJacobian(parameters,

                                                1,

                                                scratch_.get(),

                                                gradient));

}

bool GradientProblem::Plus(const double* x,

                           const double* delta,

                           double* x_plus_delta) const {

  return parameterization_->Plus(x, delta, x_plus_delta);

}

}  // namespace ceres