ossimRationalNumber Class Reference

#include <ossimRationalNumber.h>

Public Member Functions
	ossimRationalNumber ()
	ossimRationalNumber (ossim_int32 num, ossim_int32 den)
	ossimRationalNumber (ossim_int32 num)
double	toDouble () const
float	toFloat () const
void	normalize ()
const ossimRationalNumber &	operator= (ossim_int32 n)
const ossimRationalNumber &	operator= (double n)
ossimRationalNumber	operator- () const
const ossimRationalNumber &	operator+= (const ossimRationalNumber &r)
const ossimRationalNumber &	operator-= (const ossimRationalNumber &r)
const ossimRationalNumber &	operator*= (const ossimRationalNumber &r)
const ossimRationalNumber &	operator/= (const ossimRationalNumber &r)
const ossimRationalNumber &	operator+= (ossim_int32 i)
const ossimRationalNumber &	operator-= (ossim_int32 i)
const ossimRationalNumber &	operator*= (ossim_int32 i)
const ossimRationalNumber &	operator/= (ossim_int32 i)
ossimRationalNumber	operator+ (const ossimRationalNumber &r) const
ossimRationalNumber	operator- (const ossimRationalNumber &r) const
ossimRationalNumber	operator* (const ossimRationalNumber &r) const
ossimRationalNumber	operator/ (const ossimRationalNumber &r) const
ossimRationalNumber	operator+ (ossim_int32 i) const
ossimRationalNumber	operator- (ossim_int32 i) const
ossimRationalNumber	operator* (ossim_int32 i) const
ossimRationalNumber	operator/ (ossim_int32 i) const
bool	operator== (const ossimRationalNumber &r) const
bool	operator== (ossim_int32 i) const
const ossimRationalNumber &	operator++ ()
const ossimRationalNumber &	operator-- ()
const ossimRationalNumber &	assign (ossim_int32 n, ossim_int32 d)
const ossimRationalNumber &	assign (double value, long precision=10000)

Public Attributes
ossim_int32	theNum
ossim_int32	theDen

Friends
std::ostream &	operator<< (std::ostream &out, const ossimRationalNumber &rhs)
ossimRationalNumber	operator+ (ossim_int32 i, ossimRationalNumber &r)
ossimRationalNumber	operator- (ossim_int32 i, ossimRationalNumber &r)
ossimRationalNumber	operator* (ossim_int32 i, ossimRationalNumber &r)
ossimRationalNumber	operator/ (ossim_int32 i, ossimRationalNumber &r)

Detailed Description

Definition at line 15 of file ossimRationalNumber.h.

Constructor & Destructor Documentation

ossimRationalNumber() [1/3]

ossimRationalNumber::ossimRationalNumber ( )

inline

Definition at line 25 of file ossimRationalNumber.h.

Referenced by operator*(), operator*=(), operator+(), operator+=(), operator-(), operator-=(), operator/(), and operator/=().

      :theNum(1),
       theDen(1)
      {
      }

ossimRationalNumber() [2/3]

ossimRationalNumber::ossimRationalNumber ( ossim_int32  num, ossim_int32  den  )

inline

Definition at line 30 of file ossimRationalNumber.h.

      :theNum(num),
       theDen(den)
      {
      }

ossimRationalNumber() [3/3]

ossimRationalNumber::ossimRationalNumber ( ossim_int32  num )

inline

Definition at line 36 of file ossimRationalNumber.h.

      :theNum(num),
       theDen(1)
      {}

Member Function Documentation

assign() [1/2]

const ossimRationalNumber & ossimRationalNumber::assign ( ossim_int32  n, ossim_int32  d  )

inline

Definition at line 122 of file ossimRationalNumber.h.

References n, normalize(), theDen, and theNum.

{
   theNum = n;
   theDen = d;
   normalize();
   
   return *this;  
}

assign() [2/2]

const ossimRationalNumber & ossimRationalNumber::assign	(	double	value,
		long	precision = 10000
	)

default estimation is out to the 10000 place. Will set this rational to a value that is close to the passed in number.

Definition at line 39 of file ossimRationalNumber.cpp.

References normalize(), and theNum.

{
  ossim_sint32 s = 1;
  if(value <= 0.0)
    {
      s = -1;
      value *= -1.0;
    }
  ossim_int32 integerPart = (ossim_int32)std::floor(value);
  ossim_int32 decimalPart = (ossim_int32)((value - integerPart)*precision);
  ossimRationalNumber temp(integerPart);
  ossimRationalNumber temp2(decimalPart, precision);
  temp2.normalize();
  *this = (temp + temp2);
  theNum *= s; 
  normalize();
  return *this;
}

normalize()

void ossimRationalNumber::normalize

(

)

Definition at line 12 of file ossimRationalNumber.cpp.

References ossim::gcd(), theDen, and theNum.

Referenced by assign().

{
    if (theDen == 0)
    {
       return;
    }

    // Handle the case of zero separately, to avoid division by zero
    if (theNum == 0)
    {
       theDen = 1;
       return;
    }

    ossim_int32 g = ossim::gcd(theNum, theDen);
    
    theNum /= g;
    theDen /= g;

    // Ensure that the denominator is positive
    if (theDen < 0)
    {
       theNum = -theNum;
       theDen = -theDen;
    }
}

operator*() [1/2]

ossimRationalNumber ossimRationalNumber::operator*

(

const ossimRationalNumber &

r

)

const

Definition at line 197 of file ossimRationalNumber.cpp.

References ossim::gcd(), theDen, and theNum.

Referenced by operator*().

{
   ossimRationalNumber result = *this;
   // Avoid overflow and preserve normalization
   ossim_int32 gcd1 = ossim::gcd(result.theNum, r.theDen);
   ossim_int32 gcd2 = ossim::gcd(r.theNum, result.theDen);
   result.theNum = (result.theNum/gcd1) * (r.theNum/gcd2);
   result.theDen = (result.theDen/gcd2) * (r.theDen/gcd1);
   
   return result;
}

operator*() [2/2]

ossimRationalNumber ossimRationalNumber::operator* ( ossim_int32  i ) const

inline

Definition at line 142 of file ossimRationalNumber.h.

References operator*(), and ossimRationalNumber().

{
    return operator * (ossimRationalNumber(i));
}

operator*=() [1/2]

const ossimRationalNumber & ossimRationalNumber::operator*=

(

const ossimRationalNumber &

r

)

Definition at line 102 of file ossimRationalNumber.cpp.

References ossim::gcd(), theDen, and theNum.

Referenced by operator*=().

{
    // Avoid overflow and preserve normalization
    ossim_int32 gcd1 = ossim::gcd(theNum, r.theDen);
    ossim_int32 gcd2 = ossim::gcd(r.theNum, theDen);
    theNum = (theNum/gcd1) * (r.theNum/gcd2);
    theDen = (theDen/gcd2) * (r.theDen/gcd1);
    
    return *this;
}

operator*=() [2/2]

const ossimRationalNumber & ossimRationalNumber::operator*= ( ossim_int32  i )

inline

Definition at line 140 of file ossimRationalNumber.cpp.

References operator*=(), and ossimRationalNumber().

{
    return operator *= (ossimRationalNumber(i));
}

operator+() [1/2]

ossimRationalNumber ossimRationalNumber::operator+

(

const ossimRationalNumber &

r

)

const

Definition at line 150 of file ossimRationalNumber.cpp.

References ossim::gcd(), ossimRationalNumber(), theDen, and theNum.

Referenced by operator+().

{
    // This calculation avoids overflow, and minimises the number of expensive
    // calculations. Thanks to Nickolay Mladenov for this algorithm.
    //
    // Proof:
    // We have to compute a/b + c/d, where gcd(a,b)=1 and gcd(b,c)=1.
    // Let g = gcd(b,d), and b = b1*g, d=d1*g. Then gcd(b1,d1)=1
    //
    // The result is (a*d1 + c*b1) / (b1*d1*g).
    // Now we have to normalize this ratio.
    // Let's assume h | gcd((a*d1 + c*b1), (b1*d1*g)), and h > 1
    // If h | b1 then gcd(h,d1)=1 and hence h|(a*d1+c*b1) => h|a.
    // But since gcd(a,b1)=1 we have h=1.
    // Similarly h|d1 leads to h=1.
    // So we have that h | gcd((a*d1 + c*b1) , (b1*d1*g)) => h|g
    // Finally we have gcd((a*d1 + c*b1), (b1*d1*g)) = gcd((a*d1 + c*b1), g)
    // Which proves that instead of normalizing the result, it is better to
    // divide num and den by gcd((a*d1 + c*b1), g)

   ossim_int32 g = ossim::gcd(theDen, r.theDen);
   ossim_int32 den = theDen;
   ossim_int32 num = theNum;
   den /= g;  // = b1 from the calculations above
   num = num * (r.theDen / g) + r.theNum * den;
   g = ossim::gcd(num, g);
   num /= g;
   den *= r.theDen/g;

    return ossimRationalNumber(num, den);
}

operator+() [2/2]

ossimRationalNumber ossimRationalNumber::operator+ ( ossim_int32  i ) const

inline

Definition at line 132 of file ossimRationalNumber.h.

References operator+(), and ossimRationalNumber().

{
    return operator + (ossimRationalNumber(i));
}

operator++()

const ossimRationalNumber & ossimRationalNumber::operator++ ( )

inline

Definition at line 172 of file ossimRationalNumber.h.

References theDen, and theNum.

{
   theNum += theDen;
   
   return *this;
}

operator+=() [1/2]

const ossimRationalNumber & ossimRationalNumber::operator+=

(

const ossimRationalNumber &

r

)

Definition at line 58 of file ossimRationalNumber.cpp.

References ossim::gcd(), theDen, and theNum.

Referenced by operator+=().

{
    // This calculation avoids overflow, and minimises the number of expensive
    // calculations. Thanks to Nickolay Mladenov for this algorithm.
    //
    // Proof:
    // We have to compute a/b + c/d, where gcd(a,b)=1 and gcd(b,c)=1.
    // Let g = gcd(b,d), and b = b1*g, d=d1*g. Then gcd(b1,d1)=1
    //
    // The result is (a*d1 + c*b1) / (b1*d1*g).
    // Now we have to normalize this ratio.
    // Let's assume h | gcd((a*d1 + c*b1), (b1*d1*g)), and h > 1
    // If h | b1 then gcd(h,d1)=1 and hence h|(a*d1+c*b1) => h|a.
    // But since gcd(a,b1)=1 we have h=1.
    // Similarly h|d1 leads to h=1.
    // So we have that h | gcd((a*d1 + c*b1) , (b1*d1*g)) => h|g
    // Finally we have gcd((a*d1 + c*b1), (b1*d1*g)) = gcd((a*d1 + c*b1), g)
    // Which proves that instead of normalizing the result, it is better to
    // divide num and den by gcd((a*d1 + c*b1), g)

    ossim_int32 g = ossim::gcd(theDen, r.theDen);
    theDen /= g;  // = b1 from the calculations above
    theNum = theNum * (r.theDen / g) + r.theNum * theDen;
    g = ossim::gcd(theNum, g);
    theNum /= g;
    theDen *= r.theDen/g;

    return *this;
}

operator+=() [2/2]

const ossimRationalNumber & ossimRationalNumber::operator+= ( ossim_int32  i )

inline

Definition at line 130 of file ossimRationalNumber.cpp.

References operator+=(), and ossimRationalNumber().

{
    return operator += (ossimRationalNumber(i));
}

operator-() [1/3]

ossimRationalNumber ossimRationalNumber::operator- ( ) const

inline

Definition at line 63 of file ossimRationalNumber.h.

Referenced by operator-().

      {
         return ossimRationalNumber(-theNum, theDen);
      }

operator-() [2/3]

ossimRationalNumber ossimRationalNumber::operator-

(

const ossimRationalNumber &

r

)

const

Definition at line 182 of file ossimRationalNumber.cpp.

References ossim::gcd(), theDen, and theNum.

{
   ossimRationalNumber result = *this;
    // This calculation avoids overflow, and minimises the number of expensive
    // calculations. It corresponds exactly to the += case above
    ossim_int32 g = ossim::gcd(result.theDen, r.theDen);
    result.theDen /= g;
    result.theNum = result.theNum * (r.theDen / g) - r.theNum * result.theDen;
    g = ossim::gcd(result.theNum, g);
    result.theNum /= g;
    result.theDen *= r.theDen/g;

    return result;
}

operator-() [3/3]

ossimRationalNumber ossimRationalNumber::operator- ( ossim_int32  i ) const

inline

Definition at line 137 of file ossimRationalNumber.h.

References operator-(), and ossimRationalNumber().

{
    return operator - (ossimRationalNumber(i));
}

operator--()

const ossimRationalNumber & ossimRationalNumber::operator-- ( )

inline

Definition at line 179 of file ossimRationalNumber.h.

References theDen, and theNum.

{
   theNum -= theDen;
   
   return *this;   
}

operator-=() [1/2]

const ossimRationalNumber & ossimRationalNumber::operator-=

(

const ossimRationalNumber &

r

)

Definition at line 88 of file ossimRationalNumber.cpp.

References ossim::gcd(), theDen, and theNum.

Referenced by operator-=().

{
    // This calculation avoids overflow, and minimises the number of expensive
    // calculations. It corresponds exactly to the += case above
    ossim_int32 g = ossim::gcd(theDen, r.theDen);
    theDen /= g;
    theNum = theNum * (r.theDen / g) - r.theNum * theDen;
    g = ossim::gcd(theNum, g);
    theNum /= g;
    theDen *= r.theDen/g;

    return *this;
}

operator-=() [2/2]

const ossimRationalNumber & ossimRationalNumber::operator-= ( ossim_int32  i )

inline

Definition at line 135 of file ossimRationalNumber.cpp.

References operator-=(), and ossimRationalNumber().

{
    return operator -= (ossimRationalNumber(i));
}

operator/() [1/2]

ossimRationalNumber ossimRationalNumber::operator/

(

const ossimRationalNumber &

r

)

const

Definition at line 209 of file ossimRationalNumber.cpp.

References OSSIM_INT_NAN, ossimRationalNumber(), theDen, and theNum.

Referenced by operator/().

{
   ossim_int32 zero(0);
   
   if (r.theNum == zero)
   {
      return ossimRationalNumber(OSSIM_INT_NAN, OSSIM_INT_NAN);;
   }
   
   return (*this)*(ossimRationalNumber(r.theDen, r.theNum));
}

operator/() [2/2]

ossimRationalNumber ossimRationalNumber::operator/ ( ossim_int32  i ) const

inline

Definition at line 147 of file ossimRationalNumber.h.

References operator/(), and ossimRationalNumber().

{
    return operator / (ossimRationalNumber(i));
}

operator/=() [1/2]

const ossimRationalNumber & ossimRationalNumber::operator/=

(

const ossimRationalNumber &

r

)

Definition at line 113 of file ossimRationalNumber.cpp.

References OSSIM_INT_NAN, ossimRationalNumber(), theDen, and theNum.

Referenced by operator/=().

{
   ossim_int32 zero(0);
   
   if (r.theNum == zero)
   {
      theNum = OSSIM_INT_NAN;
      theDen = OSSIM_INT_NAN;
      
      return *this;
   }
   *this = (*this)*(ossimRationalNumber(r.theDen, r.theNum));

   return *this;
}

operator/=() [2/2]

const ossimRationalNumber & ossimRationalNumber::operator/= ( ossim_int32  i )

inline

Definition at line 145 of file ossimRationalNumber.cpp.

References operator/=(), and ossimRationalNumber().

{
    return operator /= (ossimRationalNumber(i));
}

operator=() [1/2]

const ossimRationalNumber& ossimRationalNumber::operator= ( ossim_int32  n )

inline

Definition at line 53 of file ossimRationalNumber.h.

References n.

      {
         return assign(n, 1);
      }

operator=() [2/2]

const ossimRationalNumber& ossimRationalNumber::operator= ( double  n )

inline

Definition at line 58 of file ossimRationalNumber.h.

References n.

      {
         return assign(n);
      }

operator==() [1/2]

bool ossimRationalNumber::operator== ( const ossimRationalNumber &  r ) const

inline

Definition at line 186 of file ossimRationalNumber.h.

References theDen, and theNum.

{
    return ((theNum == r.theNum) && (theDen == r.theDen));
}

operator==() [2/2]

bool ossimRationalNumber::operator== ( ossim_int32  i ) const

inline

Definition at line 191 of file ossimRationalNumber.h.

References theDen, and theNum.

{
    return ((theDen == ossim_int32(1)) && (theNum == i));
}

toDouble()

double ossimRationalNumber::toDouble ( ) const

inline

Definition at line 40 of file ossimRationalNumber.h.

      {
         return (static_cast<double>(theNum)/
                 static_cast<double>(theDen));
      }

toFloat()

float ossimRationalNumber::toFloat ( ) const

inline

Definition at line 45 of file ossimRationalNumber.h.

      {
         return (static_cast<float>(theNum)/
                 static_cast<float>(theDen));
      }

Friends And Related Function Documentation

operator*

ossimRationalNumber operator* ( ossim_int32  i, ossimRationalNumber &  r  )

friend

Definition at line 162 of file ossimRationalNumber.h.

{
   return ossimRationalNumber(i)*r;
}

operator+

ossimRationalNumber operator+ ( ossim_int32  i, ossimRationalNumber &  r  )

friend

Definition at line 152 of file ossimRationalNumber.h.

{
   return ossimRationalNumber(i)+r;
}

operator-

ossimRationalNumber operator- ( ossim_int32  i, ossimRationalNumber &  r  )

friend

Definition at line 157 of file ossimRationalNumber.h.

{
   return ossimRationalNumber(i)-r;
}

operator/

ossimRationalNumber operator/ ( ossim_int32  i, ossimRationalNumber &  r  )

friend

Definition at line 167 of file ossimRationalNumber.h.

{
   return ossimRationalNumber(i)/r;
}

operator<<

std::ostream& operator<< ( std::ostream &  out, const ossimRationalNumber &  rhs  )

friend

Definition at line 19 of file ossimRationalNumber.h.

      {
         out<<rhs.theNum << "/" << rhs.theDen;
         
         return out;
      }

Member Data Documentation

theDen

ossim_int32 ossimRationalNumber::theDen

Holds the value of the denominator.

Definition at line 118 of file ossimRationalNumber.h.

Referenced by assign(), normalize(), operator*(), operator*=(), operator+(), operator++(), operator+=(), operator-(), operator--(), operator-=(), operator/(), operator/=(), and operator==().

theNum

ossim_int32 ossimRationalNumber::theNum

Holds the value of the numberator.

Definition at line 113 of file ossimRationalNumber.h.

Referenced by assign(), normalize(), operator*(), operator*=(), operator+(), operator++(), operator+=(), operator-(), operator--(), operator-=(), operator/(), operator/=(), and operator==().

---

The documentation for this class was generated from the following files:

• ossimRationalNumber.h
• ossimRationalNumber.cpp