static RtreeValue rtreeValueDown(sqlite3_value *v){
  double d = sqlite3_value_double(v);
  float f = (float)d;
  if( f>d ){
    f = (float)(d*(d<0 ? RNDAWAY : RNDTOWARDS));
  }
  return f;
}
static RtreeValue rtreeValueDown(sqlite3_value *v){
  double d = sqlite3_value_double(v);
  float f = (float)d;
  if( f>d ){
    f = (float)(d*(d<0 ? RNDAWAY : RNDTOWARDS));
  }
  return f;
}