# include <float.h>
# include <math.h>
# include <stdio.h>
# include <stdlib.h>

# include "closest_point_brute.h"

//****************************************************************************80

void closest_point_brute ( int m, int nr, double r[], double s[], 
  int &near_index, double &near_dist )

//****************************************************************************80
//
//  Purpose:
//
//    closest_point_brute() finds the nearest R point to an S point.
//
//  Discussion:
//
//    We are given R, a set of NR points in M dimensions.
//
//    We are given S, a point in M dimensions.
//
//    We seek the index J of the point R(J)
//    which is nearest to S over all points in R.
//
//  Licensing:
//
//    This code is distributed under the MIT license.
//
//  Modified:
//
//    15 August 2024
//
//  Author:
//
//    John Burkardt
//
//  Input:
//
//    int M, the spatial dimension.
//
//    int NR, the number of data points.
//
//    double R[M*NR], the data points.
//
//    double S[M], the point whose nearest R value is desired.
//
//  Output:
//
//    int near_index: the index of the nearest data point.
//
//    double near_dist: the distance of the nearest data point.
//
{
  double dist_sq;
  int i;
  int jr;

  near_dist = DBL_MAX;
  near_index = -1;

  for ( jr = 0; jr < nr; jr++ )
  {
    dist_sq = 0.0;
    for ( i = 0; i < m; i++ )
    {
      dist_sq = dist_sq + pow ( r[i+jr*m] - s[i], 2 );
    }

    if ( dist_sq < near_dist )
    {
      near_dist = dist_sq;
      near_index = jr;
    }
  }

  near_dist = sqrt ( near_dist );

  return;
}