--- trunk/src/primitives/Torsion.cpp	2005/10/20 20:27:34	692
+++ trunk/src/primitives/Torsion.cpp	2006/05/17 21:51:42	963
@@ -47,7 +47,8 @@ namespace oopse {
 		   TorsionType *tt) :
     atom1_(atom1), atom2_(atom2), atom3_(atom3), atom4_(atom4), torsionType_(tt) { }
 
-  void Torsion::calcForce() {
+  void Torsion::calcForce(RealType& angle) {
+
     Vector3d pos1 = atom1_->getPos();
     Vector3d pos2 = atom2_->getPos();
     Vector3d pos3 = atom3_->getPos();
@@ -59,68 +60,39 @@ namespace oopse {
 
     //  Calculate the cross products and distances
     Vector3d A = cross(r21, r32);
-    double rA = A.length();
+    RealType rA = A.length();
     Vector3d B = cross(r32, r43);
-    double rB = B.length();
+    RealType rB = B.length();
     Vector3d C = cross(r32, A);
-    double rC = C.length();
+    RealType rC = C.length();
 
     A.normalize();
     B.normalize();
     C.normalize();
     
     //  Calculate the sin and cos
-    double cos_phi = dot(A, B) ;
-    double sin_phi = dot(C, B);
+    RealType cos_phi = dot(A, B) ;
+    if (cos_phi > 1.0) cos_phi = 1.0;
+    if (cos_phi < -1.0) cos_phi = -1.0; 
 
-    double dVdPhi;
-    torsionType_->calcForce(cos_phi, sin_phi, potential_, dVdPhi);
-
+    RealType dVdcosPhi;
+    torsionType_->calcForce(cos_phi, potential_, dVdcosPhi);
     Vector3d f1;
     Vector3d f2;
     Vector3d f3;
 
-    if (fabs(sin_phi) > 0.5) {
-    //use the sin version to  prevent potential singularities
-
     Vector3d dcosdA = (cos_phi * A - B) /rA;
     Vector3d dcosdB = (cos_phi * B - A) /rB;
 
-    double dVdcosPhi = -dVdPhi / sin_phi;
-
     f1 = dVdcosPhi * cross(r32, dcosdA);
     f2 = dVdcosPhi * ( cross(r43, dcosdB) - cross(r21, dcosdA));
     f3 = dVdcosPhi * cross(dcosdB, r32);
-
-    } else {
-    //use the cos version to  prevent potential singularities
-
-    double dVdsinPhi = dVdPhi /cos_phi;
-    Vector3d dsindB = (sin_phi * B - C) /rB;
-    Vector3d dsindC = (sin_phi * C - B) /rC;
-
-    f1.x() = dVdsinPhi*((r32.y()*r32.y() + r32.z()*r32.z())*dsindC.x() - r32.x()*r32.y()*dsindC.y() - r32.x()*r32.z()*dsindC.z());
-
-    f1.y() = dVdsinPhi*((r32.z()*r32.z() + r32.x()*r32.x())*dsindC.y() - r32.y()*r32.z()*dsindC.z() - r32.y()*r32.x()*dsindC.x());
-
-    f1.z() = dVdsinPhi*((r32.x()*r32.x() + r32.y()*r32.y())*dsindC.z() - r32.z()*r32.x()*dsindC.x() - r32.z()*r32.y()*dsindC.y());
-
-    f2.x() = dVdsinPhi*(-(r32.y()*r21.y() + r32.z()*r21.z())*dsindC.x() + (2.0*r32.x()*r21.y() - r21.x()*r32.y())*dsindC.y()
-    + (2.0*r32.x()*r21.z() - r21.x()*r32.z())*dsindC.z() + dsindB.z()*r43.y() - dsindB.y()*r43.z());
-
-    f2.y() = dVdsinPhi*(-(r32.z()*r21.z() + r32.x()*r21.x())*dsindC.y() + (2.0*r32.y()*r21.z() - r21.y()*r32.z())*dsindC.z()
-    + (2.0*r32.y()*r21.x() - r21.y()*r32.x())*dsindC.x() + dsindB.x()*r43.z() - dsindB.z()*r43.x());
-
-    f2.z() = dVdsinPhi*(-(r32.x()*r21.x() + r32.y()*r21.y())*dsindC.z() + (2.0*r32.z()*r21.x() - r21.z()*r32.x())*dsindC.x()
-    +(2.0*r32.z()*r21.y() - r21.z()*r32.y())*dsindC.y() + dsindB.y()*r43.x() - dsindB.x()*r43.y());
-
-    f3 = dVdsinPhi * cross(dsindB, r32);
-    }
-
+    
     atom1_->addFrc(f1);
     atom2_->addFrc(f2 - f1);
     atom3_->addFrc(f3 - f2);
     atom4_->addFrc(-f3);
+    angle = acos(cos_phi) /M_PI * 180.0;
   }
 
 }