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element.h

/***************************************************************************
 *   Copyright (C) 2003-2004 by David Saxton                               *
 *   david@bluehaze.org                                                    *
 *                                                                         *
 *   This program is free software; you can redistribute it and/or modify  *
 *   it under the terms of the GNU General Public License as published by  *
 *   the Free Software Foundation; either version 2 of the License, or     *
 *   (at your option) any later version.                                   *
 ***************************************************************************/

#ifndef ELEMENT_H
#define ELEMENT_H

#include "elementset.h"
#include "matrix.h"

class ElementSet;
class Vector;
typedef unsigned int uint;

const double T = 300.; // Temperature in Kelvin
const double K = 1.38e-23; // Boltzmann's constant
const double q = 1.602e-19; // Charge on an electron
const double V_T = K*T/q; // Thermal voltage
const double gmin = 1e-12; // Minimum parallel conductance used in dc domain

class CNode
{
public:
      CNode();
      void set_n( const uint n ) { m_n=n; }
      uint n() { return m_n; }
      double v; // Voltage on node. This is set from the last calculated voltage.
      bool isGround; // True for ground nodes. Obviously, you should ignore n and v if this is true
private:
      uint m_n; // CNode number
};

class CBranch
{
public:
      CBranch();
      void set_n( const uint n ) { m_n=n; }
      uint n() { return m_n; }
      double i; // Current flowing through branch. This is set from the last calculated current.
private:
      uint m_n; // CBranch number
};

const int MAX_CNODES = 4;

// Default node number that represents no node (remember that
// Ground node is -1, and the rest are numbered from 0 to n-1
const int noCNode = -2;
// Likewise for branch (although there is no "ground" branch;
// it is merely -2 for likeness with noCNode)
const int noBranch = -2;

/**
@short Represents a circuit element (such as resistance)
@author David Saxton
*/
00063 class Element
{
public:
      enum Type
      {
            Element_BJT,
            Element_Capacitance,
            Element_CCCS,
            Element_CCVS,
            Element_CurrentSignal,
            Element_CurrentSource,
            Element_Diode,
            Element_Inductance,
            Element_LogicIn,
            Element_LogicOut,
            Element_OpAmp,
            Element_Resistance,
            Element_VCCS,
            Element_VCVS,
            Element_VoltagePoint,
            Element_VoltageSignal,
            Element_VoltageSource
      };
      
      Element();
      virtual ~Element();
      /**
       * This must be called when the circuit is changed. The function will get
       * all the required pointers from ElementSet
       */
      virtual void setElementSet( ElementSet *c );
      /**
       * Returns a pointer to the current element set
       */
00097       ElementSet *elementSet() { return p_eSet; }
      /**
       * Tells the element which nodes to use. Remember that -1 is ground. You
       * should refer to the individual elements for which nodes are used for what.
       */
      void setCNodes( const int n0 = noCNode, const int n1 = noCNode, const int n2 = noCNode, const int n3 = noCNode );
      /**
       * Tells the element it's branch numbers (if it should have one). Not
       * all elements use this.
       */
      void setCBranches( const int b0 = noBranch, const int b1 = noBranch, const int b2 = noBranch, const int b3 = noBranch );
      /**
       * Returns a pointer to the given CNode
       */
00111       CNode *cnode( const uint num ) { return p_cnode[num]; }
      /**
       * Returns a pointer to the given CNode
       */
00115       CBranch *cbranch( const uint num ) { return p_cbranch[num]; }
      /**
       * Returns the number of branches used by the element
       */
00119       int numCBranches() { return m_numCBranches; }
      /**
       * Returns the number of circuit nodes used by the element
       */
00123       int numCNodes() { return m_numCNodes; }
      /**
       * Call this function to tell the element to calculate the
       * current flowing *into* it's cnodes *from* the element. You
       * can get the currents with m_cnodeI. Child class must implement this function.
       */
      virtual void updateCurrents() = 0;
      /**
       * Returns true for reactive elements that need stepping for numerical-integration
       * (such as capacitors)
       */
00134       virtual bool isReactive() { return false; }
      /**
       * Returns true for NonLinear elements that need iteration to converge to a solution
       * as the matrix A is a function of x.
       */
00139       virtual bool isNonLinear() { return false; }
      /**
       * Returns the type of element
       */
      virtual Type type() const = 0;
      /**
       * Call this function to tell the element to add its map to the matrix in use
       */
00147       virtual void add_map() {};
      /**
       * Does the required MNA stuff. This should be called from ElementSet when necessary.
       */
      virtual void add_initial_dc() = 0;
      /**
       * This is called from the Component destructor. When elementSetDeleted has
       * also been called, this class will delete itself.
       */
       void componentDeleted();
       void elementSetDeleted();
      
00159       double m_cnodeI[8]; ///< Current flowing into the cnodes from the element
      double cbranchCurrent( const int branch );
      double cnodeVoltage( const int node );
      
protected:
      /**
       * Resets all calculated currents in the nodes to 0
       */
      void resetCurrents();
      
      inline double & A_g( uint i, uint j );
      inline double & A_b( uint i, uint j );
      inline double & A_c( uint i, uint j );
      inline double & A_d( uint i, uint j );
      
      inline double & b_i( uint i );
      inline double & b_v( uint i );
      
      ElementSet *p_eSet;
      Matrix *p_A;
      Vector *p_b;
      CNode *p_cnode[MAX_CNODES];
      CBranch *p_cbranch[4];
      
      /**
       * True when the element can do add_initial_dc(), i.e. when it has
       * pointers to the circuit, and at least one of its nodes is not ground.
       */
00187       bool b_status;
      /**
       * Update the status, returning b_status
       */
      virtual bool updateStatus();
      /**
       * Set by child class - the number of branches that the element uses
       * Typically, this is 0, but could be 1 (e.g. independent voltage source)
       * or 2 (e.g. cccs)
       */
00197       int m_numCBranches;
      /**
       * Set by child class - the number of circuit nodes that the element uses
       */
00201       int m_numCNodes;
      
private:
      bool b_componentDeleted;
      bool b_eSetDeleted; 
      double m_temp;
};


double & Element::A_g( uint i, uint j )
{
      if ( p_cnode[i]->isGround || p_cnode[j]->isGround )
            return m_temp;
      return p_A->g( p_cnode[i]->n(), p_cnode[j]->n() );
}


double & Element::A_b( uint i, uint j )
{
      if ( p_cnode[i]->isGround )
            return m_temp;
      return p_A->b( p_cnode[i]->n(), p_cbranch[j]->n() );
}


double & Element::A_c( uint i, uint j )
{
      if ( p_cnode[j]->isGround )
            return m_temp;
      return p_A->c( p_cbranch[i]->n(), p_cnode[j]->n() );
}


double & Element::A_d( uint i, uint j )
{
      return p_A->d( p_cbranch[i]->n(), p_cbranch[j]->n() );
}



double & Element::b_i( uint i )
{
      if ( p_cnode[i]->isGround )
            return m_temp;
      
      return (*p_b)[ p_cnode[i]->n() ];
}


double & Element::b_v( uint i )
{
      return (*p_b)[ p_eSet->cnodeCount() + p_cbranch[i]->n() ];
}

#endif

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