65 k3_(k3), k2_(k2), k1_(k1), k0_(k0) {}
67 void setForceConstant(RealType k3, RealType k2, RealType k1, RealType k0) {
74 void getForceConstant(RealType& k3, RealType& k2, RealType& k1,
82 virtual void calcForce(RealType cosPhi, RealType& V, RealType& dVdCosPhi) {
83 RealType cosPhi2 = cosPhi * cosPhi;
84 RealType cosPhi3 = cosPhi2 * cosPhi;
86 V = k0_ + k1_ * cosPhi + k2_ * cosPhi2 + k3_ * cosPhi3;
87 dVdCosPhi = k1_ + 2.0 * k2_ * cosPhi + 3.0 * k3_ * cosPhi2;