RealQuadEquation Struct Reference

#include <RealQuadEquation.h>

Public Member Functions
	RealQuadEquation (double A, double B, double C)

Public Attributes
double	first
bool	hasSolution
double	second

Detailed Description

A numericaly stable and as fast as can be quadratic equation solver. The equation has the form A*x^2 + B*x + C = 0

Definition at line 11 of file RealQuadEquation.h.

Constructor & Destructor Documentation

RealQuadEquation::RealQuadEquation ( double  A, double  B, double  C  )

inline

Definition at line 17 of file RealQuadEquation.h.

References patCaloMETCorrections_cff::A, patCaloMETCorrections_cff::C, lumiQueryAPI::q, and mathSSE::sqrt().

                                                  {
    double D = B*B - 4*A*C;
    if (D<0) hasSolution = false;
    else {
      hasSolution = true;
      auto q = -0.5*(B + std::copysign(std::sqrt(D),B));
      first = q/A;
      second = C/q;
    }
  }

Member Data Documentation

double RealQuadEquation::first

Definition at line 13 of file RealQuadEquation.h.

Referenced by HelixBarrelCylinderCrossing::HelixBarrelCylinderCrossing(), and HelixBarrelPlaneCrossingByCircle::pathLength().

bool RealQuadEquation::hasSolution

Definition at line 15 of file RealQuadEquation.h.

Referenced by HelixBarrelCylinderCrossing::HelixBarrelCylinderCrossing(), and HelixBarrelPlaneCrossingByCircle::pathLength().

double RealQuadEquation::second

Definition at line 14 of file RealQuadEquation.h.

Referenced by HelixBarrelCylinderCrossing::HelixBarrelCylinderCrossing(), and HelixBarrelPlaneCrossingByCircle::pathLength().