Re: Decimal Floating Point (DFP) and does Perl needs DFP?

As a side note, Perl 6 has a built-in Rat (rational number) class, so that if I write:

my $c = 1/3;
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it will apparently store internally "1/3", a Rat type, not "0.333333...".

I suppose this will remove some of the problems associated with floating point calculations, but probably not all of them.

Je suis Charlie.

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Re^2: Decimal Floating Point (DFP) and does Perl needs DFP? by syphilis (Archbishop) on Jan 17, 2015 at 23:58 UTC
Perl 6 has a built-in Rat (rational number) class It'll be interesting to see how well that performs and what limitations it has. (Are denominator and numerator limited to ivsize ?) Perl5 does provide access to rational arithmetic via Math::BigRat (which is slow) and Math::GMPq (which is fast, but requires the gmp library). Cheers, Rob	[reply]
Re^3: Decimal Floating Point (DFP) and does Perl needs DFP? by raiph (Deacon) on Jan 20, 2015 at 05:50 UTC
Comparing a 2014.08 Rakudo with Perl 5.20 running the rat_mul_div_cancel micro benchmark showed "Rat (rational number) support is 6x faster than Perl 5". To quote the user doc for Rat: "To prevent the numerator and denominator from becoming pathologically large, the denominator is limited to 64 bit storage. On overflow of the denominator a Num (floating-point number) is returned instead." and "If you want arbitrary precision arithmetic with rational numbers, use the FatRat type instead." »ö« ^{. o O ( "the celebrity tell-all of the Perl-6 cult?" )}	[reply]
Re^2: Decimal Floating Point (DFP) and does Perl needs DFP? by flexvault (Monsignor) on Jan 17, 2015 at 13:03 UTC
Hello Laurent_R, Yes, but it's still in the software. It is one of the features of Perl 6 that I look forward to...Ed Regards...Ed "Well done is better than well said." - Benjamin Franklin	[reply]