286 lines
11 KiB
C++
286 lines
11 KiB
C++
/*%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
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Header: FGFunction.h
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Author: Jon Berndt
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Date started: August 25 2004
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------------- Copyright (C) 2001 Jon S. Berndt (jon@jsbsim.org) -------------
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This program is free software; you can redistribute it and/or modify it under
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the terms of the GNU Lesser General Public License as published by the Free Software
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Foundation; either version 2 of the License, or (at your option) any later
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version.
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This program is distributed in the hope that it will be useful, but WITHOUT
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ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
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FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public License for more
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details.
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You should have received a copy of the GNU Lesser General Public License along with
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this program; if not, write to the Free Software Foundation, Inc., 59 Temple
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Place - Suite 330, Boston, MA 02111-1307, USA.
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Further information about the GNU Lesser General Public License can also be found on
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the world wide web at http://www.gnu.org.
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%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
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SENTRY
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%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%*/
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#ifndef FGFUNCTION_H
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#define FGFUNCTION_H
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/*%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
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INCLUDES
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%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%*/
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#include <vector>
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#include <string>
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#include "FGParameter.h"
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/*%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
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DEFINITIONS
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%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%*/
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#define ID_FUNCTION "$Id: FGFunction.h,v 1.26 2012/09/25 12:43:13 jberndt Exp $"
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/*%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
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FORWARD DECLARATIONS
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%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%*/
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namespace JSBSim {
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class FGPropertyManager;
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class Element;
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/*%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
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CLASS DOCUMENTATION
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%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%*/
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/** Represents a mathematical function.
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The FGFunction class is a powerful and versatile resource that allows
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algebraic functions to be defined in a JSBSim configuration file. It is
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similar in concept to MathML (Mathematical Markup Language, www.w3.org/Math/),
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but simpler and more terse.
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A function definition consists of an operation, a value, a table, or a property
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(which evaluates to a value). The currently supported operations are:
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- sum (takes n args)
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- difference (takes n args)
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- product (takes n args)
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- quotient (takes 2 args)
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- pow (takes 2 args)
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- exp (takes 2 args)
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- log2 (takes 1 arg)
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- ln (takes 1 arg)
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- log10 (takes 1 arg)
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- abs (takes n args)
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- sin (takes 1 arg)
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- cos (takes 1 arg)
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- tan (takes 1 arg)
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- asin (takes 1 arg)
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- acos (takes 1 arg)
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- atan (takes 1 arg)
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- atan2 (takes 2 args)
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- min (takes n args)
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- max (takes n args)
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- avg (takes n args)
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- fraction
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- mod
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- lt (less than, takes 2 args)
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- le (less equal, takes 2 args)
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- gt (greater than, takes 2 args)
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- ge (greater than, takes 2 args)
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- eq (equal, takes 2 args)
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- nq (not equal, takes 2 args)
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- and (takes n args)
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- or (takes n args)
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- not (takes 1 args)
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- if-then (takes 2-3 args)
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- switch (takes 2 or more args)
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- random (Gaussian distribution random number)
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- urandom (Uniform random number between -1 and +1)
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- pi
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- integer
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- interpolate 1-dimensional (takes a minimum of five arguments, odd number)
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An operation is defined in the configuration file as in the following example:
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@code
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<sum>
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<value> 3.14159 </value>
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<property> velocities/qbar </property>
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<product>
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<value> 0.125 </value>
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<property> metrics/wingarea </property>
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</product>
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</sum>
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@endcode
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A full function definition, such as is used in the aerodynamics section of a
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configuration file includes the function element, and other elements. It should
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be noted that there can be only one non-optional (non-documentation) element -
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that is, one operation element - in the top-level function definition.
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Multiple value and/or property elements cannot be immediate child
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members of the function element. Almost always, the first operation within the
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function element will be a product or sum. For example:
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@code
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<function name="aero/coefficient/Clr">
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<description>Roll moment due to yaw rate</description>
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<product>
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<property>aero/qbar-area</property>
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<property>metrics/bw-ft</property>
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<property>aero/bi2vel</property>
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<property>velocities/r-aero-rad_sec</property>
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<table>
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<independentVar>aero/alpha-rad</independentVar>
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<tableData>
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0.000 0.08
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0.094 0.19
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</tableData>
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</table>
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</product>
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</function>
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@endcode
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The "lowest level" in a function is always a value or a property, which cannot
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itself contain another element. As shown, operations can contain values,
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properties, tables, or other operations. In the first above example, the sum
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element contains all three. What is evaluated is written algebraically as:
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@code 3.14159 + qbar + (0.125 * wingarea) @endcode
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Some operations can take only a single argument. That argument, however, can be
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an operation (such as sum) which can contain other items. The point to keep in
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mind is that it evaluates to a single value - which is just what the trigonometric
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functions require (except atan2, which takes two arguments).
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@author Jon Berndt
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*/
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/*%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
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DECLARATION: FGFunction
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%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%*/
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// Todo: Does this class need a copy constructor, like FGLGear?
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class FGFunction : public FGParameter
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{
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public:
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/** Constructor.
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When this constructor is called, the XML element pointed to in memory by the
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element argument is traversed. If other FGParameter-derived objects (values,
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functions, properties, or tables) are encountered, this instance of the
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FGFunction object will store a pointer to the found object and pass the relevant
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Element pointer to the constructor for the new object. In other words, each
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FGFunction object maintains a list of "child" FGParameter-derived objects which
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in turn may each contain its own list, and so on. At runtime, each object
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evaluates its child parameters, which each may have its own child parameters to
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evaluate.
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@param PropertyManager a pointer to the property manager instance.
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@param element a pointer to the Element object containing the function definition.
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@param prefix an optional prefix to prepend to the name given to the property
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that represents this function (if given).
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*/
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FGFunction(FGPropertyManager* PropertyManager, Element* element, const std::string& prefix="");
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/// Destructor.
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virtual ~FGFunction();
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/** Retrieves the value of the function object.
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@return the total value of the function. */
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double GetValue(void) const;
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/** The value that the function evaluates to, as a string.
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@return the value of the function as a string. */
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std::string GetValueAsString(void) const;
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/// Retrieves the name of the function.
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std::string GetName(void) const {return Name;}
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/** Specifies whether to cache the value of the function, so it is calculated only
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once per frame.
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If shouldCache is true, then the value of the function is calculated, and
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a flag is set so further calculations done this frame will use the cached value.
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In order to turn off caching, cacheValue must be called with a false argument.
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@param shouldCache specifies whether the function should cache the computed value. */
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void cacheValue(bool shouldCache);
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private:
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std::vector <FGParameter*> Parameters;
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FGPropertyManager* const PropertyManager;
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bool cached;
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double invlog2val;
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std::string Prefix;
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static const std::string description_string;
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static const std::string property_string;
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static const std::string value_string;
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static const std::string table_string;
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static const std::string p_string;
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static const std::string v_string;
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static const std::string t_string;
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static const std::string function_string;
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static const std::string sum_string;
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static const std::string difference_string;
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static const std::string product_string;
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static const std::string quotient_string;
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static const std::string pow_string;
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static const std::string exp_string;
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static const std::string log2_string;
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static const std::string ln_string;
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static const std::string log10_string;
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static const std::string abs_string;
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static const std::string sign_string;
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static const std::string sin_string;
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static const std::string cos_string;
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static const std::string tan_string;
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static const std::string asin_string;
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static const std::string acos_string;
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static const std::string atan_string;
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static const std::string atan2_string;
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static const std::string pi_string;
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static const std::string min_string;
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static const std::string max_string;
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static const std::string avg_string;
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static const std::string fraction_string;
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static const std::string mod_string;
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static const std::string random_string;
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static const std::string urandom_string;
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static const std::string integer_string;
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static const std::string rotation_alpha_local_string;
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static const std::string rotation_beta_local_string;
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static const std::string rotation_gamma_local_string;
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static const std::string rotation_bf_to_wf_string;
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static const std::string rotation_wf_to_bf_string;
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static const std::string lessthan_string;
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static const std::string lessequal_string;
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static const std::string greatthan_string;
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static const std::string greatequal_string;
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static const std::string equal_string;
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static const std::string notequal_string;
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static const std::string and_string;
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static const std::string or_string;
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static const std::string not_string;
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static const std::string ifthen_string;
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static const std::string switch_string;
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static const std::string interpolate1d_string;
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double cachedValue;
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enum functionType {eTopLevel=0, eProduct, eDifference, eSum, eQuotient, ePow,
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eExp, eAbs, eSign, eSin, eCos, eTan, eASin, eACos, eATan, eATan2,
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eMin, eMax, eAvg, eFrac, eInteger, eMod, eRandom, eUrandom, ePi,
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eLog2, eLn, eLog10, eLT, eLE, eGE, eGT, eEQ, eNE, eAND, eOR, eNOT,
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eIfThen, eSwitch, eInterpolate1D, eRotation_alpha_local,
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eRotation_beta_local, eRotation_gamma_local, eRotation_bf_to_wf,
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eRotation_wf_to_bf} Type;
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std::string Name;
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std::string sCopyTo; // Property name to copy function value to
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FGPropertyManager* pCopyTo; // Property node for CopyTo property string
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unsigned int GetBinary(double) const;
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void bind(void);
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void Debug(int from);
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};
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} // namespace JSBSim
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#endif
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