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merged: AboutEqual() from chk branch 

deleted: properties svn:mime-type from ttmath.h
         (it was for testing viewvc)


git-svn-id: svn://ttmath.org/publicrep/ttmath/trunk@186 e52654a7-88a9-db11-a3e9-0013d4bc506e
This commit is contained in:
Tomasz Sowa 2009-09-05 16:43:38 +00:00
parent 3544a1df3c
commit 0d71b0cec2
2 changed files with 74 additions and 1 deletions
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4
CHANGELOG
View File

@ -1,4 +1,4 @@
Version 0.9.0 prerelease (2009.08.04):
Version 0.9.0 prerelease (2009.09.05):
* added: support for wide characters (wchar_t)
wide characters are used when macro TTMATH_USE_WCHAR is defined
this macro is defined automatically when there is macro UNICODE or _UNICODE defined
@ -20,6 +20,8 @@ Version 0.9.0 prerelease (2009.08.04):
* added: multithread support for Big<> class
you should compile with TTMATH_MULTITHREADS
and use TTMATH_MULTITHREADS_HELPER macro somewhere in your *.cpp file
* added: Big::AboutEqual(const Big<exp,man> & ss2, int nBitsToIgnore = 4)
the last nBitsToIgnore bits from mantissas will be skipped when comparing
* changed: Factorial() is using the Gamma() function now
* removed: Parser<>::SetFactorialMax() method
the factorial() is such a fast now that we don't need the method longer

71
ttmath/ttmathbig.h
View File

@ -3916,6 +3916,77 @@ public:
}
bool AboutEqual(const Big<exp,man> & ss2, int nBitsToIgnore = 4) const
{
// we should check the mantissas beforehand because sometimes we can have
// a mantissa set to zero but in the exponent something another value
// (maybe we've forgotten about calling CorrectZero() ?)
if( mantissa.IsZero() )
{
if( ss2.mantissa.IsZero() )
return true;
return(ss2.AboutEqual(*this,nBitsToIgnore));
}
if( ss2.mantissa.IsZero() )
{
return(this->exponent <= uint(2*(-sint(man*TTMATH_BITS_PER_UINT))+nBitsToIgnore));
}
// exponents may not differ much!
ttmath::Int<exp> expdiff(this->exponent - ss2.exponent);
// they may differ one if for example mantissa1=0x80000000, mantissa2=0xffffffff
if( ttmath::Abs(expdiff) > 1 )
return(false);
// calculate the 'difference' mantissa
ttmath::UInt<man> man1(this->mantissa);
ttmath::UInt<man> man2(ss2.mantissa);
ttmath::UInt<man> mandiff;
switch( expdiff.ToInt() )
{
case +1:
man2.Rcr(1,0);
mandiff = man1;
mandiff.Sub(man2);
break;
case -1:
man1.Rcr(1,0);
mandiff = man2;
mandiff.Sub(man1);
break;
default:
if( man2 > man1 )
{
mandiff = man2;
mandiff.Sub(man1);
}
else
{
mandiff = man1;
mandiff.Sub(man2);
}
break;
}
// faster to mask the bits!
TTMATH_ASSERT( nBitsToIgnore < TTMATH_BITS_PER_UINT );
for( int n = man-1; n > 0; --n )
{
if( mandiff.table[n] != 0 )
return(false);
}
uint nMask = ~((1 << nBitsToIgnore) - 1);
return((mandiff.table[0] & nMask) == 0);
}
bool operator<(const Big<exp,man> & ss2) const
{
if( IsSign() && !ss2.IsSign() )