cpu_slope_limiters.hpp

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/*
This file is part of Vlasiator.
Copyright 2013, 2014 Finnish Meteorological Institute
 
*/
 
#ifndef CPU_SLOPE_LIMITERS_H
#define CPU_SLOPE_LIMITERS_H
 
using namespace std;

 
inline Real slope_limiter(const Real& l,const Real& m, const Real& r) {
  Real sign;
  Real a=r-m;
  Real b=m-l; 
  Real minval=min(2.0 * abs(a), 2.0 * abs(b));
  minval=min(minval, (Real)(0.5 * abs(a+b)));
  
  //check for extrema
  Real output = a*b < 0 ? 0.0 : minval;
  //set sign
  return a + b < 0 ? -output : output;
}

void slope_limiter(const Real& l,const Real& m, const Real& r, Real& slope_abs, Real& slope_sign) {
  Real sign;
  Real a=r-m;
  Real b=m-l; 
  Real minval=min(2.0 * abs(a),2.0 * abs(b));
  minval=min(minval, (Real)(0.5 * abs(a+b)));
  
  //check for extrema, set absolute value
  slope_abs = a*b < 0 ? 0.0: minval;
  slope_sign = a + b < 0 ? -1.0 : 1.0;
 
}
 
#endif