// 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
