flightgear/src/FDM/JSBSim/math/FGTable.h

/*%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%

 Header:       FGTable.h
 Author:       Jon S. Berndt
 Date started: 1/9/2001

 ------------- Copyright (C) 2001  Jon S. Berndt (jsb@hal-pc.org) --------------

 This program is free software; you can redistribute it and/or modify it under
 the terms of the GNU Lesser General Public License as published by the Free Software
 Foundation; either version 2 of the License, or (at your option) any later
 version.

 This program is distributed in the hope that it will be useful, but WITHOUT
 ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
 FOR A PARTICULAR PURPOSE.  See the GNU Lesser General Public License for more
 details.

 You should have received a copy of the GNU Lesser General Public License along with
 this program; if not, write to the Free Software Foundation, Inc., 59 Temple
 Place - Suite 330, Boston, MA  02111-1307, USA.

 Further information about the GNU Lesser General Public License can also be found on
 the world wide web at http://www.gnu.org.

HISTORY
--------------------------------------------------------------------------------
JSB  1/9/00          Created

%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
SENTRY
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%*/

#ifndef FGTABLE_H
#define FGTABLE_H

/*%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
INCLUDES
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%*/

#include <input_output/FGXMLElement.h>
#include "FGParameter.h"
#include <input_output/FGPropertyManager.h>
#include <sstream>
#include <vector>

/*%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
DEFINITIONS
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%*/

#define ID_TABLE "$Id$"

/*%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
FORWARD DECLARATIONS
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%*/

using std::vector;
using std::stringstream;

namespace JSBSim {

/*%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
CLASS DOCUMENTATION
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%*/

/** 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:

@code
<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>
@endcode

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:

@code
<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>
@endcode

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:

@code
<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>
@endcode

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

@code
<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>
@endcode

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

@code
<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>
@endcode

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

Here's an example:

@code
<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>
@endcode

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:

@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;
@endcode

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:

@code
combustion_efficiency = Lookup_Combustion_Efficiency->GetValue(equivalence_ratio);
@endcode

@author Jon S. Berndt
@version $Id$
*/

/*%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
CLASS DECLARATION
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%*/

class FGTable : public FGParameter
{
public:
  /// Destructor
  ~FGTable();

  /** This is the very important copy constructor.
      @param table a const reference to a table.*/
  FGTable(const FGTable& table);

  /// The constructor for a table
  FGTable (FGPropertyManager* propMan, Element* el);
  FGTable (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;
  /** 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:
      <pre>
           0  10  20 30 ...
      -5   1  2   3  4  ...
       ...
       </pre>

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

      <pre>
       0.0
           0  10  20 30 ...
      -5   1  2   3  4  ...
       ...
       </pre>
       */

  void operator<<(stringstream&);
  FGTable& operator<<(const double n);
  FGTable& operator<<(const int n);

  inline double GetElement(int r, int c) {return Data[r][c];}
  inline double GetElement(int r, int c, int t);

  void SetRowIndexProperty(FGPropertyManager *node) {lookupProperty[eRow] = node;}
  void SetColumnIndexProperty(FGPropertyManager *node) {lookupProperty[eColumn] = node;}

  void Print(void);

private:
  enum type {tt1D, tt2D, tt3D} Type;
  enum axis {eRow=0, eColumn, eTable};
  bool internal;
  FGPropertyManager *lookupProperty[3];
  double** Data;
  vector <FGTable*> Tables;
  int  FindNumColumns(string);
  int nRows, nCols, nTables, dimension;
  int colCounter, rowCounter, tableCounter;
  mutable int lastRowIndex, lastColumnIndex, lastTableIndex;
  double** Allocate(void);
  FGPropertyManager* const PropertyManager;
  string Name;
  void bind(void);

  void Debug(int from);
};
}
//%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%

#endif