include/HepPDT/Measurement.icc

0001 // ----------------------------------------------------------------------
0002 //
0003 // Measurement.icc
0004 // author:  Mark Fischler
0005 // ----------------------------------------------------------------------
0006
0007 #include <algorithm>    // swap()
0008
0009 namespace HepPDT {
0010
0011 inline double NaN() {
0012   // A byte-order-independent way to return a non-signalling NaN
0013   struct Dib {
0014     union {
0015       double d;
0016       int   i[2];
0017     } u;
0018   };
0019   Dib pos3_2;
0020   Dib posTwo;
0021   pos3_2.u.d =  1.5;  // Leading bit of mantissa = 1 --> quiet NaN
0022   posTwo.u.d =  2.0;
0023   Dib value;
0024   value.u.i[0] = pos3_2.u.i[0] | posTwo.u.i[0];
0025   value.u.i[1] = pos3_2.u.i[1] | posTwo.u.i[1];
0026   return value.u.d;
0027 }
0028
0029
0030 Measurement::Measurement ( double value, double sigma ) :
0031   val(value), sig(sigma)  {}
0032
0033 Measurement::Measurement () : val(NaN()), sig(NaN())  {}
0034
0035 Measurement::Measurement ( const Measurement &m ) :
0036   val( m.val ), sig( m.sig )  {}
0037
0038 void Measurement::swap( Measurement & other )
0039 {
0040   std::swap( val, other.val );
0041   std::swap( sig, other.sig );
0042 }
0043
0044 Measurement& Measurement::operator = ( Measurement const & rhs )
0045 {
0046     Measurement temp( rhs );
0047     swap( temp );
0048     return *this;
0049 }
0050
0051 bool  Measurement::operator <  ( Measurement const & other ) const
0052 {
0053   return val < other.val;
0054 }
0055
0056 bool  Measurement::operator == ( Measurement const & other ) const
0057 {
0058   return val == other.val;
0059 }
0060
0061 double Measurement::value() const { return val; }
0062 double Measurement::sigma() const { return sig; }
0063
0064 Measurement::operator double() const { return value(); }
0065
0066
0067 }  // HepPDT