BLCMDcornerarc Class Reference

Inheritance diagram for BLCMDcornerarc:

List of all members.

---

Detailed Description

class BLCMDcornerarc - implements a cornerarc in the centerline.

A cornerarc is an approximation to an arc in the centerline, implemented by 3 corners such that the overall bend angle and centerline path length are the same as the arc would be.

The error (largest distance between the arc and the actual centerline) increases with angle, but is less than 10% of radius for 90 degrees.

Public Member Functions
	BLCMDcornerarc ()
	Default constructor.
	~BLCMDcornerarc ()
	Destructor.
	BLCMDcornerarc (const BLCMDcornerarc &r)
	Copy constructor.
G4String	commandName ()
	commandName() returns "cornerarc".
int	command (BLArgumentVector &argv, BLArgumentMap &namedArgs)
	command() implements the cornerarc command.
void	defineNamedArgs ()
	defineNamedArgs() defines the named arguments for the command.
Private Attributes
G4double	z
G4double	centerRadius
G4double	angle
G4String	rotation
G4double	radiusCut
G4double	finalZ

---

Constructor & Destructor Documentation

BLCMDcornerarc::BLCMDcornerarc

(

)

Default constructor.

References angle, BLCMDTYPE_LAYOUT, centerRadius, finalZ, radiusCut, BLCommand::registerCommand(), rotation, BLCommand::setDescription(), BLCommand::setSynopsis(), and z.

Referenced by command().

                               : BLCommand(), rotation()
{
        registerCommand(BLCMDTYPE_LAYOUT);
        setSynopsis("Implement a cornerarc in the centerline.");
        setDescription("The centerline is bent by a rotation.\n"
                "Three corners are used to approximate an arc; the total\n"
                "angle and path-length are equal to those for the arc.\n"
                "Should be used immediately after an idealsectorbend or\n"
                "a genericbend.\n"
                "The z value is for the front face of the arc.\n"
                "\nNOTE: This command is self-placing, do not use the place\n"
                "command; it also affects all following placements, and\n"
                "it cannot be issued inside a group.\n\n"
                "This command is well matched to a sector bend, but can also "
                "be used with a normal bending magnet -- normally the magnet "
                "is placed before the cornerarc and is rotated by half the "
                "bend angle.\n\n"
                "The only useful rotations are those around the centerline Z.\n"
                "\nz, angle, and centerRadius are required parameters.\n"
                "\nNOTE: all placements before this command must have z\n"
                "values before the corner, and all placements after this\n"
                "command must have z values after the corner. Note also\n"
                "that the angle is limited to 90 degrees.\n\n"
                "Note that the radiusCut is important to reduce or eliminate "
                "ambiguities in the global to centerline coordinate transform. "
                "It can also be used to 'shield' the beamline to prevent "
                "particles from taking unusual paths around the outside "
                "of beamline elements.");
        // initial field values
        z = 0.0;
        centerRadius=0.0;
        angle = 0.0;
        rotation = "";
        radiusCut = 0.0;
        finalZ = 0.0;
}

BLCMDcornerarc::~BLCMDcornerarc

(

)

Destructor.

{
}

BLCMDcornerarc::BLCMDcornerarc

(

const BLCMDcornerarc &

r

)

Copy constructor.

References angle, centerRadius, finalZ, radiusCut, rotation, and z.

                                                      : BLCommand(r), rotation(r.rotation)
{
        z = r.z;
        centerRadius = r.centerRadius;
        angle = r.angle;
        rotation = r.rotation;
        radiusCut = r.radiusCut;
        finalZ = 0.0;
}

---

Member Function Documentation

G4String BLCMDcornerarc::commandName

(

)

[inline, virtual]

commandName() returns "cornerarc".

Implements BLCommand.

{ return "cornerarc"; }

int BLCMDcornerarc::command	(	BLArgumentVector &	argv,
		BLArgumentMap &	namedArgs
	)			[virtual]

command() implements the cornerarc command.

Implements BLCommand.

References angle, BLCMDcornerarc(), centerRadius, BLCoordinates::corner(), finalZ, BLGroup::getCurrent(), BLGroup::getWorld(), BLCommand::handleNamedArgs(), Param, BLCommand::print(), BLCommand::printError(), radiusCut, rotation, BLParam::setParam(), BLCommand::stringToRotationMatrix(), and z.

{
        if(argv.size() >= 1 && argv[0] == "default") {
                return defaultCornerArc.handleNamedArgs(namedArgs);
        }

        if(BLGroup::getWorld() != BLGroup::getCurrent()) {
                printError("cornerarc: cannot be issued inside a group.");
                return -1;
        }

        BLCMDcornerarc *t = new BLCMDcornerarc(defaultCornerArc);
        t->z = -DBL_MAX;
        int retval = t->handleNamedArgs(namedArgs);

        if(t->z == -DBL_MAX) {
                printError("cornerarc: z must be specified");
                return -1;
        }

        G4double angleAbs = fabs(t->angle);

        if(angleAbs < 0.001 || angleAbs > 3.1416/2.0) {
                printError("cornerarc: invalid angle (0<|angle|<=90 degrees)");
                return -1;
        }
        if(t->centerRadius < 0.001*mm) {
                printError("cornerarc: invalid centerRadius");
                return -1;
        }

        // Compute the angles for the 3 corners that approximate the arc
        G4double beta = acos(sin(angleAbs/2.0)/(angleAbs/2.0));
        G4double phi1 = angleAbs/2.0 - beta;
        G4double phi2 = beta + beta;
        G4double deltaz = t->centerRadius * angleAbs / 2.0;

        // get the rotationMatrix-s
        char temp[64];
        int i = sprintf(temp,"Y%.6f",(t->angle>0.0 ? phi1 : -phi1)/deg);
        if(t->rotation.size() > 0)
                sprintf(temp+i,",%s",t->rotation.c_str());
        G4RotationMatrix matrix1 = *stringToRotationMatrix(temp);
        i = sprintf(temp,"Y%.6f",(t->angle>0.0 ? phi2 : -phi2)/deg);
        G4RotationMatrix matrix2 = *stringToRotationMatrix(temp);
        i = sprintf(temp,"Y%.6f",(t->angle>0.0 ? phi1 : -phi1)/deg);
        G4RotationMatrix matrix3 = *stringToRotationMatrix(temp);

        BLCoordinates::corner(t->z,&matrix1,t->radiusCut);
        BLCoordinates::corner(t->z+deltaz,&matrix2,t->radiusCut);
        BLCoordinates::corner(t->z+deltaz+deltaz,&matrix3,t->radiusCut);

        t->finalZ = t->z+deltaz+deltaz;

        Param.setParam("Zcl",t->finalZ);

        t->print("");

        return retval;
}

void BLCMDcornerarc::defineNamedArgs

(

)

[virtual]

defineNamedArgs() defines the named arguments for the command.

Reimplemented from BLCommand.

References angle, BLCommand::argDouble(), BLCommand::argString(), centerRadius, radiusCut, rotation, and z.

{
        argDouble(z,"z","The centerline Z of the cornerarc (mm).",mm);
        argDouble(centerRadius,"centerRadius","The radius of the centerline arc (mm).",mm);
        argDouble(angle,"angle","The angle of bend, >0=left, <0=right (degrees).",deg);
        argString(rotation,"rotation","The rotation of the cornerarc (see above).");
        argDouble(radiusCut,"radiusCut","The radius cut for this following segment (mm).",mm);
}

---

Member Data Documentation

G4double BLCMDcornerarc::z [private]

Referenced by BLCMDcornerarc(), command(), and defineNamedArgs().

G4double BLCMDcornerarc::centerRadius [private]

Referenced by BLCMDcornerarc(), command(), and defineNamedArgs().

G4double BLCMDcornerarc::angle [private]

Referenced by BLCMDcornerarc(), command(), and defineNamedArgs().

G4String BLCMDcornerarc::rotation [private]

Referenced by BLCMDcornerarc(), command(), and defineNamedArgs().

G4double BLCMDcornerarc::radiusCut [private]

Referenced by BLCMDcornerarc(), command(), and defineNamedArgs().

G4double BLCMDcornerarc::finalZ [private]

Referenced by BLCMDcornerarc(), and command().

---

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

• BLCMDcornerarc.cc