JSBSim::FGTable Class Reference

Lookup table class. More...

#include <FGTable.h>

Inherits JSBSim::FGParameter, and JSBSim::FGJSBBase.

Inherited by FGTurbulenceSeverityTable.

Public Member Functions
	~FGTable ()
	Destructor.
	FGTable (const FGTable &table)
	This is the very important copy constructor.
	FGTable (FGPropertyManager *propMan, Element *el, const std::string &prefix="")
	The constructor for a table.
	FGTable (int)
	FGTable (int, int)
double	GetValue (void) const
double	GetValue (double key) const
double	GetValue (double rowKey, double colKey) const
double	GetValue (double rowKey, double colKey, double TableKey) const
void	operator<< (std::istream &)
	Read the table in.
FGTable &	operator<< (const double n)
FGTable &	operator<< (const int n)
double	GetElement (int r, int c) const
double	operator() (unsigned int r, unsigned int c) const
void	SetRowIndexProperty (FGPropertyNode *node)
void	SetColumnIndexProperty (FGPropertyNode *node)
unsigned int	GetNumRows () const
void	Print (void)
std::string	GetName (void) const
Public Member Functions inherited from JSBSim::FGParameter
virtual	~FGParameter (void)
virtual bool	IsConstant (void) const
double	getDoubleValue (void) const
Public Member Functions inherited from JSBSim::FGJSBBase
	FGJSBBase ()
	Constructor for FGJSBBase.
virtual	~FGJSBBase ()
	Destructor for FGJSBBase.
void	PutMessage (const Message &msg)
	Places a Message structure on the Message queue.
void	PutMessage (const std::string &text)
	Creates a message with the given text and places it on the queue.
void	PutMessage (const std::string &text, bool bVal)
	Creates a message with the given text and boolean value and places it on the queue.
void	PutMessage (const std::string &text, int iVal)
	Creates a message with the given text and integer value and places it on the queue.
void	PutMessage (const std::string &text, double dVal)
	Creates a message with the given text and double value and places it on the queue.
int	SomeMessages (void) const
	Reads the message on the queue (but does not delete it).
void	ProcessMessage (void)
	Reads the message on the queue and removes it from the queue.
Message *	ProcessNextMessage (void)
	Reads the next message on the queue and removes it from the queue.
void	disableHighLighting (void)
	Disables highlighting in the console output.

Additional Inherited Members
Public Types inherited from JSBSim::FGJSBBase
enum	{ eL = 1 , eM , eN }
	Moments L, M, N. More...
enum	{ eP = 1 , eQ , eR }
	Rates P, Q, R. More...
enum	{ eU = 1 , eV , eW }
	Velocities U, V, W. More...
enum	{ eX = 1 , eY , eZ }
	Positions X, Y, Z. More...
enum	{ ePhi = 1 , eTht , ePsi }
	Euler angles Phi, Theta, Psi. More...
enum	{ eDrag = 1 , eSide , eLift }
	Stability axis forces, Drag, Side force, Lift. More...
enum	{ eRoll = 1 , ePitch , eYaw }
	Local frame orientation Roll, Pitch, Yaw. More...
enum	{ eNorth = 1 , eEast , eDown }
	Local frame position North, East, Down. More...
enum	{ eLat = 1 , eLong , eRad }
	Locations Radius, Latitude, Longitude. More...
enum	{   inNone = 0 , inDegrees , inRadians , inMeters ,   inFeet }
	Conversion specifiers. More...
static const std::string &	GetVersion (void)
	Returns the version number of JSBSim.
static constexpr double	KelvinToFahrenheit (double kelvin)
	Converts from degrees Kelvin to degrees Fahrenheit.
static constexpr double	CelsiusToRankine (double celsius)
	Converts from degrees Celsius to degrees Rankine.
static constexpr double	RankineToCelsius (double rankine)
	Converts from degrees Rankine to degrees Celsius.
static constexpr double	KelvinToRankine (double kelvin)
	Converts from degrees Kelvin to degrees Rankine.
static constexpr double	RankineToKelvin (double rankine)
	Converts from degrees Rankine to degrees Kelvin.
static constexpr double	FahrenheitToCelsius (double fahrenheit)
	Converts from degrees Fahrenheit to degrees Celsius.
static constexpr double	CelsiusToFahrenheit (double celsius)
	Converts from degrees Celsius to degrees Fahrenheit.
static constexpr double	CelsiusToKelvin (double celsius)
	Converts from degrees Celsius to degrees Kelvin.
static constexpr double	KelvinToCelsius (double kelvin)
	Converts from degrees Kelvin to degrees Celsius.
static constexpr double	FeetToMeters (double measure)
	Converts from feet to meters.
static double	PitotTotalPressure (double mach, double p)
	Compute the total pressure in front of the Pitot tube.
static double	MachFromImpactPressure (double qc, double p)
	Compute the Mach number from the differential pressure (qc) and the static pressure.
static double	VcalibratedFromMach (double mach, double p)
	Calculate the calibrated airspeed from the Mach number.
static double	MachFromVcalibrated (double vcas, double p)
	Calculate the Mach number from the calibrated airspeed.Based on the formulas in the US Air Force Aircraft Performance Flight Testing Manual (AFFTC-TIH-99-01).
static bool	EqualToRoundoff (double a, double b)
	Finite precision comparison.
static bool	EqualToRoundoff (float a, float b)
	Finite precision comparison.
static bool	EqualToRoundoff (float a, double b)
	Finite precision comparison.
static bool	EqualToRoundoff (double a, float b)
	Finite precision comparison.
static constexpr double	Constrain (double min, double value, double max)
	Constrain a value between a minimum and a maximum value.
static constexpr double	sign (double num)
static double	GaussianRandomNumber (void)
Static Public Attributes inherited from JSBSim::FGJSBBase
static char	highint [5] = {27, '[', '1', 'm', '\0' }
	highlights text
static char	halfint [5] = {27, '[', '2', 'm', '\0' }
	low intensity text
static char	normint [6] = {27, '[', '2', '2', 'm', '\0' }
	normal intensity text
static char	reset [5] = {27, '[', '0', 'm', '\0' }
	resets text properties
static char	underon [5] = {27, '[', '4', 'm', '\0' }
	underlines text
static char	underoff [6] = {27, '[', '2', '4', 'm', '\0' }
	underline off
static char	fgblue [6] = {27, '[', '3', '4', 'm', '\0' }
	blue text
static char	fgcyan [6] = {27, '[', '3', '6', 'm', '\0' }
	cyan text
static char	fgred [6] = {27, '[', '3', '1', 'm', '\0' }
	red text
static char	fggreen [6] = {27, '[', '3', '2', 'm', '\0' }
	green text
static char	fgdef [6] = {27, '[', '3', '9', 'm', '\0' }
	default text
static short	debug_lvl = 1
static std::string	CreateIndexedPropertyName (const std::string &Property, int index)
static Message	localMsg
static std::queue< Message >	Messages
static unsigned int	messageId = 0
static constexpr double	radtodeg = 180. / 3.14159265358979323846
static constexpr double	degtorad = 3.14159265358979323846 / 180.
static constexpr double	hptoftlbssec = 550.0
static constexpr double	psftoinhg = 0.014138
static constexpr double	psftopa = 47.88
static constexpr double	ktstofps = 1.68781
static constexpr double	fpstokts = 1.0 / ktstofps
static constexpr double	inchtoft = 1.0/12.0
static constexpr double	fttom = 0.3048
static constexpr double	m3toft3 = 1.0/(fttom*fttom*fttom)
static constexpr double	in3tom3 = inchtoft*inchtoft*inchtoft/m3toft3
static constexpr double	inhgtopa = 3386.38
static constexpr double	slugtolb = 32.174049
	Note that definition of lbtoslug by the inverse of slugtolb and not to a different constant you can also get from some tables will make lbtoslug*slugtolb == 1 up to the magnitude of roundoff.
static constexpr double	lbtoslug = 1.0/slugtolb
static constexpr double	kgtolb = 2.20462
static constexpr double	kgtoslug = 0.06852168
static const std::string	needed_cfg_version = "2.0"
static const std::string	JSBSim_version = JSBSIM_VERSION " " __DATE__ " " __TIME__
static int	gaussian_random_number_phase = 0

Detailed Description

Lookup table class.

Models a one, two, or three dimensional lookup table for use in aerodynamics and function definitions.

For a single "vector" lookup table, the format is as follows:

<table name="property_name">
  <independentVar lookup="row"> property_name </independentVar>
  <tableData>
    key_1 value_1
    key_2 value_2
    ...  ...
    key_n value_n
  </tableData>
</table>

The lookup="row" attribute in the independentVar element is option in this case; it is assumed that the independentVar is a row variable.

A "real life" example is as shown here:

<table>
  <independentVar lookup="row"> aero/alpha-rad </independentVar>
  <tableData>
   -1.57  1.500
   -0.26  0.033
    0.00  0.025
    0.26  0.033
    1.57  1.500
  </tableData>
</table>

The first column in the data table represents the lookup index (or "key"). In this case, the lookup index is aero/alpha-rad (angle of attack in radians). If alpha is 0.26 radians, the value returned from the lookup table would be 0.033.

The definition for a 2D table, is as follows:

<table name="property_name">
  <independentVar lookup="row"> property_name </independentVar>
  <independentVar lookup="column"> property_name </independentVar>
  <tableData>
                {col_1_key   col_2_key   ...  col_n_key }
    {row_1_key} {col_1_data  col_2_data  ...  col_n_data}
    {row_2_key} {...         ...         ...  ...       }
    { ...     } {...         ...         ...  ...       }
    {row_n_key} {...         ...         ...  ...       }
  </tableData>
</table>

The data is in a gridded format.

A "real life" example is as shown below. Alpha in radians is the row lookup (alpha breakpoints are arranged in the first column) and flap position in degrees is

<table>
  <independentVar lookup="row">aero/alpha-rad</independentVar>
  <independentVar lookup="column">fcs/flap-pos-deg</independentVar>
  <tableData>
                0.0         10.0        20.0         30.0
    -0.0523599  8.96747e-05 0.00231942  0.0059252    0.00835082
    -0.0349066  0.000313268 0.00567451  0.0108461    0.0140545
    -0.0174533  0.00201318  0.0105059   0.0172432    0.0212346
     0.0        0.0051894   0.0168137   0.0251167    0.0298909
     0.0174533  0.00993967  0.0247521   0.0346492    0.0402205
     0.0349066  0.0162201   0.0342207   0.0457119    0.0520802
     0.0523599  0.0240308   0.0452195   0.0583047    0.0654701
     0.0698132  0.0333717   0.0577485   0.0724278    0.0803902
     0.0872664  0.0442427   0.0718077   0.088081     0.0968405
  </tableData>
</table>

The definition for a 3D table in a coefficient would be (for example):

<table name="property_name">
  <independentVar lookup="row"> property_name </independentVar>
  <independentVar lookup="column"> property_name </independentVar>
  <tableData breakpoint="table_1_key">
                {col_1_key   col_2_key   ...  col_n_key }
    {row_1_key} {col_1_data  col_2_data  ...  col_n_data}
    {row_2_key} {...         ...         ...  ...       }
    { ...     } {...         ...         ...  ...       }
    {row_n_key} {...         ...         ...  ...       }
  </tableData>
  <tableData breakpoint="table_2_key">
                {col_1_key   col_2_key   ...  col_n_key }
    {row_1_key} {col_1_data  col_2_data  ...  col_n_data}
    {row_2_key} {...         ...         ...  ...       }
    { ...     } {...         ...         ...  ...       }
    {row_n_key} {...         ...         ...  ...       }
  </tableData>
  ...
  <tableData breakpoint="table_n_key">
                {col_1_key   col_2_key   ...  col_n_key }
    {row_1_key} {col_1_data  col_2_data  ...  col_n_data}
    {row_2_key} {...         ...         ...  ...       }
    { ...     } {...         ...         ...  ...       }
    {row_n_key} {...         ...         ...  ...       }
  </tableData>
</table>

[Note the "breakpoint" attribute in the tableData element, above.]

Here's an example:

<table>
  <independentVar lookup="row">fcs/row-value</independentVar>
  <independentVar lookup="column">fcs/column-value</independentVar>
  <independentVar lookup="table">fcs/table-value</independentVar>
  <tableData breakPoint="-1.0">
           -1.0     1.0
    0.0     1.0000  2.0000
    1.0     3.0000  4.0000
  </tableData>
  <tableData breakPoint="0.0000">
            0.0     10.0
    2.0     1.0000  2.0000
    3.0     3.0000  4.0000
  </tableData>
  <tableData breakPoint="1.0">
           0.0     10.0     20.0
     2.0   1.0000   2.0000   3.0000
     3.0   4.0000   5.0000   6.0000
    10.0   7.0000   8.0000   9.0000
  </tableData>
</table>

In addition to using a Table for something like a coefficient, where all the row and column elements are read in from a file, a Table could be created and populated completely within program code:

// First column is thi, second is neta (combustion efficiency)
Lookup_Combustion_Efficiency = new FGTable(12);
 
*Lookup_Combustion_Efficiency << 0.00 << 0.980;
*Lookup_Combustion_Efficiency << 0.90 << 0.980;
*Lookup_Combustion_Efficiency << 1.00 << 0.970;
*Lookup_Combustion_Efficiency << 1.05 << 0.950;
*Lookup_Combustion_Efficiency << 1.10 << 0.900;
*Lookup_Combustion_Efficiency << 1.15 << 0.850;
*Lookup_Combustion_Efficiency << 1.20 << 0.790;
*Lookup_Combustion_Efficiency << 1.30 << 0.700;
*Lookup_Combustion_Efficiency << 1.40 << 0.630;
*Lookup_Combustion_Efficiency << 1.50 << 0.570;
*Lookup_Combustion_Efficiency << 1.60 << 0.525;
*Lookup_Combustion_Efficiency << 2.00 << 0.345;

The first column in the table, above, is thi (the lookup index, or key). The second column is the output data - in this case, "neta" (the Greek letter referring to combustion efficiency). Later on, the table is used like this:

combustion_efficiency = Lookup_Combustion_Efficiency->GetValue(equivalence_ratio);

Author

Jon S. Berndt

Definition at line 233 of file FGTable.h.

Constructor & Destructor Documentation

~FGTable()

JSBSim::FGTable::~FGTable

(

)

Destructor.

Definition at line 399 of file FGTable.cpp.

FGTable() [1/4]

JSBSim::FGTable::FGTable

(

const FGTable &

table

)

This is the very important copy constructor.

Parameters

table

a const reference to a table.

Definition at line 82 of file FGTable.cpp.

FGTable() [2/4]

JSBSim::FGTable::FGTable	(	FGPropertyManager *	propMan,
		Element *	el,
		const std::string &	prefix = "" )

The constructor for a table.

Definition at line 126 of file FGTable.cpp.

FGTable() [3/4]

JSBSim::FGTable::FGTable

(

int

NRows

)

Definition at line 52 of file FGTable.cpp.

FGTable() [4/4]

JSBSim::FGTable::FGTable	(	int	NRows,
		int	NCols )

Definition at line 67 of file FGTable.cpp.

Member Function Documentation

GetElement()

double JSBSim::FGTable::GetElement ( int r, int c ) const

inline

Definition at line 277 of file FGTable.h.

GetName()

std::string JSBSim::FGTable::GetName ( void ) const

inlinevirtual

Implements JSBSim::FGParameter.

Definition at line 291 of file FGTable.h.

GetNumRows()

unsigned int JSBSim::FGTable::GetNumRows ( ) const

inline

Definition at line 287 of file FGTable.h.

GetValue() [1/4]

double JSBSim::FGTable::GetValue

(

double

key

)

const

Definition at line 453 of file FGTable.cpp.

GetValue() [2/4]

double JSBSim::FGTable::GetValue	(	double	rowKey,
		double	colKey ) const

Definition at line 496 of file FGTable.cpp.

GetValue() [3/4]

double JSBSim::FGTable::GetValue	(	double	rowKey,
		double	colKey,
		double	TableKey ) const

Definition at line 530 of file FGTable.cpp.

GetValue() [4/4]

double JSBSim::FGTable::GetValue ( void ) const

virtual

Implements JSBSim::FGParameter.

Definition at line 422 of file FGTable.cpp.

operator()()

double JSBSim::FGTable::operator() ( unsigned int r, unsigned int c ) const

inline

Definition at line 279 of file FGTable.h.

operator<<() [1/3]

FGTable & JSBSim::FGTable::operator<<

(

const double

n

)

Definition at line 594 of file FGTable.cpp.

operator<<() [2/3]

FGTable & JSBSim::FGTable::operator<<

(

const int

n

)

Definition at line 608 of file FGTable.cpp.

operator<<() [3/3]

void JSBSim::FGTable::operator<<

(

std::istream &

)

Read the table in.

Data in the config file should be in matrix format with the row independents as the first column and the column independents in the first row. The implication of this layout is that there should be no value in the upper left corner of the matrix e.g:

     0  10  20 30 ...
-5   1  2   3  4  ...
 ...
 

For multiple-table (i.e. 3D) data sets there is an additional number key in the table definition. For example:

 0.0
     0  10  20 30 ...
-5   1  2   3  4  ...
 ...
 

Print()

void JSBSim::FGTable::Print

(

void

)

Definition at line 616 of file FGTable.cpp.

SetColumnIndexProperty()

void JSBSim::FGTable::SetColumnIndexProperty ( FGPropertyNode * node )

inline

Definition at line 284 of file FGTable.h.

SetRowIndexProperty()

void JSBSim::FGTable::SetRowIndexProperty ( FGPropertyNode * node )

inline

Definition at line 282 of file FGTable.h.

---

The documentation for this class was generated from the following files:

• FGTable.h
• FGTable.cpp