FairGeoRotation.cxx

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/********************************************************************************
 *    Copyright (C) 2014 GSI Helmholtzzentrum fuer Schwerionenforschung GmbH    *
 *                                                                              *
 *              This software is distributed under the terms of the             *
 *              GNU Lesser General Public Licence (LGPL) version 3,             *
 *                  copied verbatim in the file "LICENSE"                       *
 ********************************************************************************/
//*-- AUTHOR : Ilse Koenig
//*-- Modified : 16/06/99

// FairGeoRotation
//
// This class defines a 3x3 rotation matrix.
// The data are stored in a linear array with 9 Double_t
// components.
//
// Inline functions:
//
// Constructors:
//   FairGeoRotation()
//   FairGeoRotation(const FairGeoRotation& r)
//   FairGeoRotation(const Double_t* a)
//
// Access to components:
//   Double_t operator () (Int_t) const
//   void setElement(const Double_t,const Int_t)
//
// Check for equality/inequality
//   Bool_t operator == (const FairGeoRotation&)
//   Bool_t operator != (const FairGeoRotation&)
//
// FairGeoRotation& operator = (const FairGeoRotation&);
//      assignment
//
// void setUnitMatrix()
//      sets identity matrix
//
// void setZero()
//      sets all components to 0.0
//
// Bool_t isUnitMatrix()
//      checks unity
//
// FairGeoRotation& invert()
//      inverts the matrix
//
// FairGeoRotation inverse()
//      copies the matrix and returns the inverse of the copy
//
// Double_t determinant() const;
//      returns determinate
//
// FairGeoRotation& operator *= (const FairGeoRotation&);
//      multiplies with the given rotation matrix from the right
//
// FairGeoRotation& transform(const FairGeoRotation&);
//      multiplies with the given rotation matrix from the left
//
// FairGeoVector operator * (const FairGeoVector&) const;
//      rotates a vector
//
// FairGeoRotation operator * (const FairGeoRotation&) const;
//      rotates the given rotation
//
// void print()
//      shows the matrix
//
//
// Euler Angles:
//   1. angle:  rotation around z-axis   --> x1, y1, z1=z
//   2. angle:  rotation around y1-axis  --> x2, y2=y1, z2
//   3. angle:  rotation around z2-axis  --> x3, y3, z3=z2
#include "FairGeoRotation.h"

#include <TMath.h>        // for Cos, Sin
#include <TRotMatrix.h>   // for TRotMatrix

ClassImp(FairGeoRotation);

FairGeoRotation::FairGeoRotation(const Double_t a, const Double_t b, const Double_t c)
    : TObject()
{
    // constructor taking three Euler angles
    setEulerAngles(a, b, c);
}

void FairGeoRotation::setEulerAngles(const Double_t a, const Double_t b, const Double_t c)
{
    // sets the matrix calculating the values from the given Euler angles
    const double deg2rad = 0.01745329252;
    Double_t s0 = TMath::Sin(a * deg2rad);
    Double_t c0 = TMath::Cos(a * deg2rad);
    Double_t s1 = TMath::Sin(b * deg2rad);
    Double_t c1 = TMath::Cos(b * deg2rad);
    Double_t s2 = TMath::Sin(c * deg2rad);
    Double_t c2 = TMath::Cos(c * deg2rad);
    rot[0] = c0 * c1 * c2 - s0 * s2;
    rot[1] = -c0 * c1 * s2 - s0 * c2;
    rot[2] = c0 * s1;
    rot[3] = s0 * c1 * c2 + c0 * s2;
    rot[4] = c0 * c2 - s0 * c1 * s2;
    rot[5] = s0 * s1;
    rot[6] = -s1 * c2;
    rot[7] = s1 * s2;
    rot[8] = c1;
}

Double_t FairGeoRotation::diff2(const FairGeoRotation& r) const
{
    // calculates the square of the difference between 2 matrices
    Double_t s = 0;
    for (Int_t i = 0; i < 9; i++) {
        Double_t d = rot[i] - r(i);
        s += d * d;
    }
    return s;
}

TRotMatrix* FairGeoRotation::createTRotMatrix(const Text_t* name, const Text_t* title)
{
    // creates a TRotMatrix
    // (uses a new() operator and the user has to take care to free the memory)
    TRotMatrix* t = 0;
    if (isUnitMatrix() == kTRUE) {
        return t;
    }
    Double_t a[9];
    for (Int_t i = 0; i < 3; i++) {
        for (Int_t j = 0; j < 3; j++) {
            a[j + 3 * i] = rot[i + 3 * j];
        }
    }
    t = new TRotMatrix(name, title, a);
    return t;
}