CSCWireGeometry Class Reference

#include <CSCWireGeometry.h>

Inheritance diagram for CSCWireGeometry:

Public Member Functions
virtual CSCWireGeometry *	clone () const =0
	CSCWireGeometry (double wireSpacing, double yOfFirstWire, double narrowWidthOfPlane, double wideWidthOfPlane, double lengthOfPlane)
std::pair< float, float >	equationOfWire (float wire) const
LocalPoint	intersection (float m1, float c1, float m2, float c2) const
double	lengthOfPlane () const
double	narrowWidthOfPlane () const
virtual int	nearestWire (const LocalPoint &lp) const =0
double	wideWidthOfPlane () const
virtual float	wireAngle () const =0
std::pair< LocalPoint, LocalPoint >	wireEnds (float wire) const
double	wireSpacing () const
std::vector< float >	wireValues (float wire) const
std::pair< float, float >	yLimitsOfWirePlane () const
double	yOfFirstWire () const
virtual float	yOfWire (float wire, float x=0.) const =0
virtual	~CSCWireGeometry ()

Private Attributes
double	theLengthOfPlane
double	theNarrowWidthOfPlane
double	theWideWidthOfPlane
double	theWireSpacing
double	theYOfFirstWire

Detailed Description

An ABC defining interface for geometry related to angle which wires of a detector modelled by a WireTopology make with the local x axis.

Author

Tim Cox

Definition at line 17 of file CSCWireGeometry.h.

Constructor & Destructor Documentation

virtual CSCWireGeometry::~CSCWireGeometry ( )

inlinevirtual

Definition at line 19 of file CSCWireGeometry.h.

{}

CSCWireGeometry::CSCWireGeometry ( double  wireSpacing, double  yOfFirstWire, double  narrowWidthOfPlane, double  wideWidthOfPlane, double  lengthOfPlane  )

inline

Constructor from wire spacing (in cm)

Definition at line 24 of file CSCWireGeometry.h.

                                                                                :
     theWireSpacing( wireSpacing ), theYOfFirstWire( yOfFirstWire ),
     theNarrowWidthOfPlane( narrowWidthOfPlane ), theWideWidthOfPlane( wideWidthOfPlane ),
     theLengthOfPlane( lengthOfPlane ) {}

Member Function Documentation

virtual CSCWireGeometry* CSCWireGeometry::clone ( ) const

pure virtual

Allow proper copying of derived classes via base pointer

Implemented in CSCNonslantedWireGeometry, and CSCSlantedWireGeometry.

Referenced by CSCWireTopology::CSCWireTopology(), and CSCWireTopology::operator=().

std::pair< float, float > CSCWireGeometry::equationOfWire

(

float

wire

)

const

Return slope and intercept of straight line representing a wire in 2-dim local coordinates.

The return value is a pair p with p.first = m, p.second = c, where y=mx+c.

Definition at line 176 of file CSCWireGeometry.cc.

References LogTrace, funct::tan(), wireAngle(), and yOfWire().

Referenced by CSCWireTopology::equationOfWire().

                                                                        {
  
  const float fprec = 1.E-06;

  // slope of wire
  float wangle = wireAngle(); 
  float mw = 0;
  if ( fabs(wangle) > fprec ) mw = tan( wangle );

  // intercept of wire
  float cw = yOfWire( wire );

  LogTrace("CSCWireGeometry|CSC") << "CSCWireGeometry: wire=" << wire <<
    ", wire angle = " << wangle <<
    ", intercept on y axis=" << cw;

  return std::pair<float,float>(mw, cw);
}

LocalPoint CSCWireGeometry::intersection	(	float	m1,
		float	c1,
		float	m2,
		float	c2
	)		const

2D point of intersection of two straight lines defined by
y = m1*x + c1 and y = m2*x + c2
(in local coordinates x, y)

Definition at line 7 of file CSCWireGeometry.cc.

References alignmentValidation::c1, x, and detailsBasic3DVector::y.

Referenced by wireEnds().

                                                 {

  // Calculate the point of intersection of two straight lines (in 2-dim)
  // BEWARE! Do not call with m1 = m2 ! No trapping !

  float x = (c2-c1)/(m1-m2);
  float y = (m1*c2-m2*c1)/(m1-m2);
  return LocalPoint( x, y );
}

double CSCWireGeometry::lengthOfPlane ( ) const

inline

Extent of wire plane along long axis of trapezoid

Definition at line 57 of file CSCWireGeometry.h.

References theLengthOfPlane.

Referenced by CSCWireTopology::lengthOfPlane(), wireEnds(), and yLimitsOfWirePlane().

                               {
    return theLengthOfPlane; }

double CSCWireGeometry::narrowWidthOfPlane ( ) const

inline

Extent of wire plane at narrow end of trapezoid

Definition at line 45 of file CSCWireGeometry.h.

References theNarrowWidthOfPlane.

Referenced by CSCWireTopology::narrowWidthOfPlane(), wireEnds(), and yLimitsOfWirePlane().

                                    {
    return theNarrowWidthOfPlane; }

virtual int CSCWireGeometry::nearestWire ( const LocalPoint &  lp ) const

pure virtual

The nearest (virtual) wire to a given LocalPoint. Beware that this wire might not exist or be read out!

Implemented in CSCNonslantedWireGeometry, and CSCSlantedWireGeometry.

Referenced by CSCWireTopology::channel(), and CSCWireTopology::nearestWire().

double CSCWireGeometry::wideWidthOfPlane ( ) const

inline

Extent of wire plane at wide end of trapezoid

Definition at line 51 of file CSCWireGeometry.h.

References theWideWidthOfPlane.

Referenced by CSCWireTopology::wideWidthOfPlane(), and wireEnds().

                                  {
    return theWideWidthOfPlane; }

virtual float CSCWireGeometry::wireAngle ( ) const

pure virtual

The angle of the wires w.r.t local x axis (in radians)

Implemented in CSCNonslantedWireGeometry, and CSCSlantedWireGeometry.

Referenced by equationOfWire(), CSCWireTopology::wireAngle(), wireEnds(), and yLimitsOfWirePlane().

std::pair< LocalPoint, LocalPoint > CSCWireGeometry::wireEnds

(

float

wire

)

const

Return 2-dim local coords of the two ends of a wire

The returned value is a pair of LocalPoints.

Definition at line 35 of file CSCWireGeometry.cc.

References alignmentValidation::c1, i, intersection(), j, lengthOfPlane(), LogTrace, narrowWidthOfPlane(), funct::tan(), wideWidthOfPlane(), wireAngle(), PV3DBase< T, PVType, FrameType >::x(), PV3DBase< T, PVType, FrameType >::y(), yOfFirstWire(), and yOfWire().

Referenced by CSCWireTopology::wireEnds(), and wireValues().

                                                                              {

  // return local (x, y) of each end of wire.
  // If wire does not intersect active area set all values to 0.
  
  const float fprec = 1.E-06;

  // slope of wire
  float wangle = wireAngle();
  float mw = 0;
  if ( fabs(wangle) > fprec ) mw = tan( wireAngle() );

  // intercept of wire
  float cw = yOfWire( wire );
  
  LogTrace("CSCWireGeometry|CSC") << "CSCWireGeometry: wire=" << wire <<
    ", wire angle = " << wangle <<
    ", intercept on y axis=" << cw;
  
  // Find extent of wire plane
  double ww = wideWidthOfPlane();
  double nw = narrowWidthOfPlane();
  double len = lengthOfPlane();
  
  // slope & intercept of line defining one non-parallel edge of wire-plane trapezoid
  float m1 = 2.*len/(ww-nw);
  float c1 = 0.;
  if ( fabs(wangle) < fprec ) {
    c1 = yOfFirstWire() - nw*len/(ww-nw) ; // non-ME11
  }
  else {
    c1 = -len/2. - nw*len/(ww-nw); // ME11
  }

  // slope & intercept of other non-parallel edge of wire-plane trapezoid
  float m2 = -m1;
  float c2 =  c1;

  // wire intersects edge 1 at
  LocalPoint pw1 = intersection(mw, cw, m1, c1);
  // wire intersects edge 2 at
  LocalPoint pw2 = intersection(mw, cw, m2, c2);

  float x1 = pw1.x();
  float y1 = pw1.y();

  float x2 = pw2.x();
  float y2 = pw2.y();

  LogTrace("CSCWireGeometry|CSC") << "CSCWireGeometry: wire intersects edges of plane at " <<
    "\n  x1=" << x1 << " y1=" << y1 <<
    " x2=" << x2 << " y2=" << y2;
  
  // WIRES ARE NOT TILTED?

  if ( fabs(wangle) < fprec ) {

    LogTrace("CSCWireGeometry|CSC") << "CSCWireGeometry: wires are not tilted ";
    return std::pair< LocalPoint, LocalPoint >( LocalPoint(x1,y1), LocalPoint(x2,y2) );  
  }
  
  // WIRES ARE TILTED

  // ht and hb will be used to check where wire intersects edges of wire plane
  float ht = ww/2. ;
  float hb = nw/2. ;
  float mt = 0.; // slope of top edge
  float mb = 0.; //slope of bottom edge
  float cb = -len/2.; // intercept bottom edge of wire plane
  float ct =  len/2.; // intercept top edge of wire plane
  
  LogTrace("CSCWireGeometry|CSC") <<  "CSCWireGeometry: slopes & intercepts " <<
    "\n  mt=" << mt << " ct=" << ct << " mb=" << mb << " cb=" << cb <<
    "\n  m1=" << m1 << " c1=" << c1 << " m2=" << m2 << " c2=" << c2 <<
    "\n  mw=" << mw << " cw=" << cw;
  
  // wire intersects top edge at
  LocalPoint pwt = intersection(mw, cw, mt, ct);
  // wire intersects bottom edge at
  LocalPoint pwb = intersection(mw, cw, mb, cb);
  
  // get the local coordinates
  float xt = pwt.x();
  float yt = pwt.y();
  
  float xb = pwb.x();
  float yb = pwb.y();
  
  LogTrace("CSCWireGeometry|CSC") << "CSCWireGeometry: wire intersects top & bottom of wire plane at " <<
    "\n  xt=" << xt << " yt=" << yt <<
    " xb=" << xb << " yb=" << yb ;
  
  float xWireEnd[4], yWireEnd[4];
  
  int i = 0;
  if ( fabs(x1) >= hb && fabs(x1) <= ht ) {
    // wire does intersect side edge 1 of wire plane
    xWireEnd[i] = x1;
    yWireEnd[i] = y1;
    i++;
  }
  if ( fabs(xb) <= hb ) {
    // wire does intersect bottom edge of wire plane
    xWireEnd[i] = xb;
    yWireEnd[i] = yb;
    i++;
  }
  if ( fabs(x2) >= hb && fabs(x2) <= ht ) {
    // wire does intersect side edge 2 of wire plane
    xWireEnd[i] = x2;
    yWireEnd[i] = y2;
    i++;
  }
  if ( fabs(xt) <= ht ) {
    // wire does intersect top edge of wire plane
    xWireEnd[i] = xt;
    yWireEnd[i] = yt;
    i++;
  }
  
  if ( i != 2 ) {
    // the wire does not intersect the wire plane (!)

    LogTrace("CSCWireGeometry|CSC") << "CSCWireGeometry: wire does not intersect wire plane!!";
    //     throw cms::Exception("BadCSCGeometry") << "the wire has " << i <<
    //       " ends!" << "\n";

    return std::pair< LocalPoint, LocalPoint >( LocalPoint(0.,0.), LocalPoint(0.,0.) ); 
  }
  
  LogTrace("CSCWireGeometry|CSC") << "CSCWireGeometry: ME11 wire ends ";
  for ( int j = 0; j<i; j++ ) {
    LogTrace("CSCWireGeometry|CSC") << "  x = " << xWireEnd[j] << " y = " << yWireEnd[j];
  }

  return std::pair< LocalPoint, LocalPoint >
   ( LocalPoint(xWireEnd[0],yWireEnd[0]), LocalPoint(xWireEnd[1],yWireEnd[1]) );  
}

double CSCWireGeometry::wireSpacing ( ) const

inline

The spacing between wires (cm)

Definition at line 33 of file CSCWireGeometry.h.

References theWireSpacing.

Referenced by CSCSlantedWireGeometry::nearestWire(), CSCNonslantedWireGeometry::nearestWire(), CSCWireTopology::wireSpacing(), CSCSlantedWireGeometry::yOfWire(), and CSCNonslantedWireGeometry::yOfWire().

                             {
    return theWireSpacing; }

std::vector< float > CSCWireGeometry::wireValues

(

float

wire

)

const

Return mid-point of a wire in local coordinates, and its length across the chamber volume, in a vector as x, y, length

Definition at line 18 of file CSCWireGeometry.cc.

References mathSSE::sqrt(), and wireEnds().

Referenced by CSCWireTopology::wireValues().

                                                               {

  // return x and y of mid-point of wire, and length of wire, as 3-dim vector.
  // If wire does not intersect active area the returned vector is filled with 0's.

  std::pair< LocalPoint, LocalPoint > ends = wireEnds( wire );

  std::vector<float> buf(3); // note all elem init to 0
  
  buf[0] = (ends.first.x() + ends.second.x())/2.; // x is first elem of first & second pairs
  buf[1] = (ends.first.y() + ends.second.y())/2.; // y is second elem of first & second pairs
  float d2 = (ends.first.x() - ends.second.x()) * (ends.first.x() - ends.second.x()) +
             (ends.first.y() - ends.second.y()) * (ends.first.y() - ends.second.y());
  buf[2] = sqrt(d2) ;
  return buf;
}

std::pair< float, float > CSCWireGeometry::yLimitsOfWirePlane

(

)

const

Return pair containing y extremes of wire-plane: p.first = low y, p.second= high y

This is supposed to approximate the 'sensitive' region covered by wires (and strips) but there is no sophisticated handling of edge effects, or attempt to estimate a precise region overlapped by both wires and strips.

Definition at line 197 of file CSCWireGeometry.cc.

References lengthOfPlane(), narrowWidthOfPlane(), funct::tan(), wireAngle(), and yOfFirstWire().

Referenced by CSCWireTopology::insideYOfWirePlane(), and CSCWireTopology::restrictToYOfWirePlane().

                                                               {

  const float fprec = 0.1; // wire angle is either 0 or 29 degrees = 0.506 rads
  float ylow = yOfFirstWire(); // non-ME11 chambers
  float wangle = wireAngle();  
  if ( fabs(wangle) > fprec ) {
    ylow += tan( wangle ) * narrowWidthOfPlane()/2.; // correction for ME11
  }
  float yhigh = ylow + lengthOfPlane(); // add extent of wire plane in y
  
  return std::pair<float, float>(ylow, yhigh);
}

double CSCWireGeometry::yOfFirstWire ( ) const

inline

The local y of the first wire

Definition at line 39 of file CSCWireGeometry.h.

References theYOfFirstWire.

Referenced by CSCNonslantedWireGeometry::nearestWire(), wireEnds(), yLimitsOfWirePlane(), and CSCNonslantedWireGeometry::yOfWire().

                              {
    return theYOfFirstWire; }

virtual float CSCWireGeometry::yOfWire ( float  wire, float  x = 0.  ) const

pure virtual

Local y of a given wire 'number' (float) at given x

Implemented in CSCNonslantedWireGeometry, and CSCSlantedWireGeometry.

Referenced by equationOfWire(), wireEnds(), CSCWireTopology::yOfWire(), and CSCWireTopology::yOfWireGroup().

Member Data Documentation

double CSCWireGeometry::theLengthOfPlane

private

Definition at line 119 of file CSCWireGeometry.h.

Referenced by lengthOfPlane().

double CSCWireGeometry::theNarrowWidthOfPlane

private

Definition at line 117 of file CSCWireGeometry.h.

Referenced by narrowWidthOfPlane().

double CSCWireGeometry::theWideWidthOfPlane

private

Definition at line 118 of file CSCWireGeometry.h.

Referenced by wideWidthOfPlane().

double CSCWireGeometry::theWireSpacing

private

Definition at line 115 of file CSCWireGeometry.h.

Referenced by wireSpacing().

double CSCWireGeometry::theYOfFirstWire

private

Definition at line 116 of file CSCWireGeometry.h.

Referenced by yOfFirstWire().