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Save more than 20 percent execution time by avoiding multiple calculation of properties.

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This commit is contained in:
torsten 2009-05-31 10:18:45 +00:00 committed by Tim Moore
parent 6de19758a5
commit 5917e80bf0
2 changed files with 101 additions and 37 deletions
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62
src/Environment/environment.cxx
View file

@ -140,7 +140,7 @@ void FGEnvironment::_init()
_setup_tables();
_recalc_density();
_recalc_relative_humidity();
live_update = true;
}
FGEnvironment::FGEnvironment()
@ -386,18 +386,22 @@ FGEnvironment::set_temperature_sea_level_degc (double t)
temperature_sea_level_degc = t;
if (dewpoint_sea_level_degc > t)
dewpoint_sea_level_degc = t;
if( live_update ) {
_recalc_alt_temperature();
_recalc_density();
}
}
void
FGEnvironment::set_temperature_degc (double t)
{
temperature_degc = t;
if( live_update ) {
_recalc_sl_temperature();
_recalc_density();
_recalc_relative_humidity();
}
}
void
FGEnvironment::set_dewpoint_sea_level_degc (double t)
@ -405,83 +409,105 @@ FGEnvironment::set_dewpoint_sea_level_degc (double t)
dewpoint_sea_level_degc = t;
if (temperature_sea_level_degc < t)
temperature_sea_level_degc = t;
if( live_update ) {
_recalc_alt_dewpoint();
_recalc_density();
}
}
void
FGEnvironment::set_dewpoint_degc (double t)
{
dewpoint_degc = t;
if( live_update ) {
_recalc_sl_dewpoint();
_recalc_density();
_recalc_relative_humidity();
}
}
void
FGEnvironment::set_pressure_sea_level_inhg (double p)
{
pressure_sea_level_inhg = p;
if( live_update ) {
_recalc_alt_pressure();
_recalc_density();
}
}
void
FGEnvironment::set_pressure_inhg (double p)
{
pressure_inhg = p;
if( live_update ) {
_recalc_sl_pressure();
_recalc_density();
}
}
void
FGEnvironment::set_wind_from_heading_deg (double h)
{
wind_from_heading_deg = h;
if( live_update ) {
_recalc_ne();
}
}
void
FGEnvironment::set_wind_speed_kt (double s)
{
wind_speed_kt = s;
if( live_update ) {
_recalc_ne();
}
}
void
FGEnvironment::set_wind_from_north_fps (double n)
{
wind_from_north_fps = n;
if( live_update ) {
_recalc_hdgspd();
}
}
void
FGEnvironment::set_wind_from_east_fps (double e)
{
wind_from_east_fps = e;
if( live_update ) {
_recalc_hdgspd();
}
}
void
FGEnvironment::set_wind_from_down_fps (double d)
{
wind_from_down_fps = d;
if( live_update ) {
_recalc_hdgspd();
}
}
void
FGEnvironment::set_thermal_lift_fps (double th)
{
thermal_lift_fps = th;
if( live_update ) {
_recalc_updraft();
}
}
void
FGEnvironment::set_ridge_lift_fps (double ri)
{
ridge_lift_fps = ri;
if( live_update ) {
_recalc_updraft();
}
}
void
FGEnvironment::set_turbulence_magnitude_norm (double t)
@ -499,26 +525,32 @@ void
FGEnvironment::set_elevation_ft (double e)
{
elevation_ft = e;
if( live_update ) {
_recalc_alt_temperature();
_recalc_alt_dewpoint();
_recalc_alt_pressure();
_recalc_density();
_recalc_relative_humidity();
}
}
void
FGEnvironment::set_altitude_half_to_sun_m (double alt)
{
altitude_half_to_sun_m = alt;
if( live_update ) {
_recalc_density_tropo_avg_kgm3();
}
}
void
FGEnvironment::set_altitude_tropo_top_m (double alt)
{
altitude_tropo_top_m = alt;
if( live_update ) {
_recalc_density_tropo_avg_kgm3();
}
}
void
@ -670,12 +702,26 @@ FGEnvironment::_recalc_density_tropo_avg_kgm3 ()
void
FGEnvironment::_recalc_relative_humidity ()
{
/*
double vaporpressure = 6.11 * pow(10.0, ((7.5 * dewpoint_degc) / ( 237.7 + dewpoint_degc)));
double sat_vaporpressure = 6.11 * pow(10.0, ((7.5 * temperature_degc)
/ ( 237.7 + temperature_degc)) );
relative_humidity = 100 * vaporpressure / sat_vaporpressure ;
with a little algebra, this gets the same result and spares two multiplications and one pow()
*/
double a = (7.5 * dewpoint_degc) / ( 237.7 + dewpoint_degc);
double b = (7.5 * temperature_degc) / ( 237.7 + temperature_degc);
relative_humidity = 100 * pow(10,a-b);
}
bool
FGEnvironment::set_live_update( bool _live_update )
{
bool b = live_update;
live_update = _live_update;
return b;
}
////////////////////////////////////////////////////////////////////////
@ -707,6 +753,10 @@ void
interpolate (const FGEnvironment * env1, const FGEnvironment * env2,
double fraction, FGEnvironment * result)
{
// don't calculate each internal property every time we set a single value
// we trigger that at the end of the interpolation process
bool live_update = result->set_live_update( false );
result->set_visibility_m
(do_interp(env1->get_visibility_m(),
env2->get_visibility_m(),
@ -751,6 +801,16 @@ interpolate (const FGEnvironment * env1, const FGEnvironment * env2,
(do_interp(env1->get_turbulence_rate_hz(),
env2->get_turbulence_rate_hz(),
fraction));
// calculate derived properties here to avoid duplicate expensive computations
result->_recalc_ne();
result->_recalc_alt_temperature();
result->_recalc_alt_dewpoint();
result->_recalc_alt_pressure();
result->_recalc_density();
result->_recalc_relative_humidity();
result->set_live_update(live_update);
}
// end of environment.cxx

16
src/Environment/environment.hxx
View file

@ -101,22 +101,24 @@ public:
virtual void set_altitude_half_to_sun_m (double alt);
virtual void set_altitude_tropo_top_m (double alt);
virtual bool set_live_update(bool live_update);
void _recalc_ne ();
void _recalc_alt_temperature ();
void _recalc_alt_dewpoint ();
void _recalc_alt_pressure ();
void _recalc_density ();
void _recalc_relative_humidity ();
private:
void _init();
void _recalc_hdgspd ();
void _recalc_ne ();
void _recalc_updraft ();
void _recalc_sl_temperature ();
void _recalc_alt_temperature ();
void _recalc_sl_dewpoint ();
void _recalc_alt_dewpoint ();
void _recalc_sl_pressure ();
void _recalc_alt_pressure ();
void _recalc_density ();
void _recalc_density_tropo_avg_kgm3 ();
void _recalc_relative_humidity ();
double elevation_ft;
double visibility_m;
@ -147,6 +149,8 @@ private:
double thermal_lift_fps;
double ridge_lift_fps;
bool live_update;
};
void interpolate (const FGEnvironment * env1, const FGEnvironment * env2,