// sv-7.cc
// 		A ZOOM PhysicsVectors tutorial example
//
// 		Tutorial example 6 for the SpaceVector and UnitVector class:
//
// 		Cylindrical Coordinates
//
// * Constructing vectors in Cylindrical Coordinates
// * Modifying Cylindrical Components of a Vector

// Key lines are marked by 				    // <-------------

	// Get the SpaceVector class

#include "ZMutility/ZMenvironment.h"
#include "ZMutility/FixedTypes.h"
#include "PhysicsVectors/SpaceVector.h"
#include "PhysicsVectors/UnitVector.h"
ZM_USING_NAMESPACE( zmpv )
USING( std::cout )
USING( std::endl )

	// These classes themselves pull in FixedTypes, but just to
	// remind ourselves that we are using Float8, not double, for
	// 64-bit floats...

#include "ZMutility/FixedTypes.h"
ZM_USING_NAMESPACE( zmfxt )

	// This example will use iostream output, so get that --
	// in a portable way.

#include "ZMutility/iostream"
using std::cout;
using std::endl;


int main() {

// ***** Constructing vectors in Cylindrical Coordinates

	// Here is how to construct a vector by supplying rho, phi, z
	//-----------------------------------------------------------

  Float8 rho = 3;
  Float8 phi = 30;
  Float8 z   = 4;

  SpaceVector v ( rho, phi, DEGREES, z );		    // <-------------
  cout << "v = " << v << endl;

  	// Here is how to access cylindrical coordinates of a vector
	//----------------------------------------------------------

  Float8 a = v.rho();					   // <-------------
  Float8 b = v.phi();					   // <-------------
  Float8 c = v.z();					   // <-------------

	// Note that phi() and z() have the same meaning
	// as phi() in spherical coordinates and z in
	// Cartesian coordinates.

  cout << "rho = " << v.rho() << " perp = " << v.perp() << endl;
  cout << "r   = " << v.r() << " mag = " << v.mag() << endl;
  cout << "phi = " << v.phi()
		   << " angle = " << (v.perpPart()).angle(X_HAT) << endl;


// ***** Rotating around a coordinate axis
// ***** Modifying Cylindrical Components of a Vector


	// Here is how to modify theta while keeping rho and phi fixed
	//------------------------------------------------------------

  v.set (2, 3, 4);
  cout 	<< " rho = " << v.rho()
	<< "  r  = " << v.r()
	<< " phi = " << v.phi()
	<< "  z  = " << v.z()
	<< " theta = " << v.theta() << endl;

  v.setCylTheta ( .4 );					    // <-------------
  cout 	<< " rho = " << v.rho()
	<< "  r  = " << v.r()
	<< " phi = " << v.phi()
	<< "  z  = " << v.z()
	<< " theta = " << v.theta() << endl;

  	// The usual v.theta() = whatever keeps spherical r and phi fixed

  v.setTheta( .5 );
  cout 	<< " rho = " << v.rho()
	<< "  r  = " << v.r()
	<< " phi = " << v.phi()
	<< "  z  = " << v.z()
	<< " theta = " << v.theta() << endl;

	// Here is how to modify eta while keeping rho and phi fixed
	//----------------------------------------------------------

  v.setCylEta ( .4 );					    // <-------------
  cout 	<< " rho = " << v.rho()
	<< "  r  = " << v.r()
	<< " phi = " << v.phi()
	<< "  z  = " << v.z()
	<< " eta = " << v.eta() << endl;

  return 0;

} /* end of main */