// Ceres Solver - A fast non-linear least squares minimizer
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// Author: sameeragarwal@google.com (Sameer Agarwal)

#include "ceres/normal_prior.h"

#include <cstddef>
#include <utility>
#include <vector>

#include "absl/log/check.h"
#include "ceres/internal/eigen.h"
#include "ceres/types.h"

namespace ceres {

NormalPrior::NormalPrior(const Matrix& A, Vector b) : A_(A), b_(std::move(b)) {
  CHECK_GT(b_.rows(), 0);
  CHECK_GT(A_.rows(), 0);
  CHECK_EQ(b_.rows(), A.cols());
  set_num_residuals(A_.rows());
  mutable_parameter_block_sizes()->push_back(b_.rows());
}

bool NormalPrior::Evaluate(double const* const* parameters,
                           double* residuals,
                           double** jacobians) const {
  ConstVectorRef p(parameters[0], parameter_block_sizes()[0]);
  VectorRef r(residuals, num_residuals());
  // The following line should read
  // r = A_ * (p - b_);
  // The extra eval is to get around a bug in the Eigen library.
  r = A_ * (p - b_).eval();
  if ((jacobians != nullptr) && (jacobians[0] != nullptr)) {
    MatrixRef(jacobians[0], num_residuals(), parameter_block_sizes()[0]) = A_;
  }
  return true;
}

}  // namespace ceres