gidx_distance()

static double gidx_distance ( const GIDX *  a, const GIDX *  b, int  m_is_time  )

static

Calculate the centroid->centroid distance between the boxes.

Calculate the box->box distance.

Definition at line 647 of file gserialized_gist_nd.c.

Referenced by gserialized_gist_distance(), and gserialized_gist_geog_distance().

{
  int ndims, i;
  double sum = 0;

  /* Base computation on least available dimensions */
  ndims = Min(GIDX_NDIMS(b), GIDX_NDIMS(a));
  for ( i = 0; i < ndims; ++i )
  {
    double d;
    double amin = GIDX_GET_MIN(a,i);
    double amax = GIDX_GET_MAX(a,i);
    double bmin = GIDX_GET_MIN(b,i);
    double bmax = GIDX_GET_MAX(b,i);
    POSTGIS_DEBUGF(3, "A %g - %g", amin, amax);
    POSTGIS_DEBUGF(3, "B %g - %g", bmin, bmax);

    if ( ( amin <= bmax && amax >= bmin ) )
    {
      /* overlaps */
      d = 0;
    }
    else if ( i == 4 && m_is_time )
    {
      return FLT_MAX;
    }
    else if ( bmax < amin )
    {
      /* is "left" */
      d = amin - bmax;
    }
    else
    {
      /* is "right" */
      assert( bmin > amax );
      d = bmin - amax;
    }
    if ( ! isfinite(d) )
    {
      /* Can happen if coordinates are corrupted/NaN */
      continue;
    }
    sum += d * d;
    POSTGIS_DEBUGF(3, "dist %g, squared %g, grows sum to %g", d, d*d, sum);
  }
  return sqrt(sum);
}

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