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Google Can't Subtract  (View post)

Sunil [PersonRank 1]

Monday, December 12, 2005
18 years ago

Maybe subtraction is evil.... ;-)

Olive [PersonRank 0]

18 years ago #

That's is about half the Planck's constant ;)

Jamcnair [PersonRank 1]

18 years ago #

I sense subtle floating point rounding errors at work here.

Lalufu [PersonRank 1]

18 years ago #

Some floating point numbers do not have a representation that fits into a limited number of bits. Try "perl -e 'print (1 – 0.9 – 0.1)'" on a perl capable machine, it will most likely print the same.

Olive [PersonRank 0]

18 years ago #

I meant twice the Planck's constant. Nevermind :D

runner108 [PersonRank 1]

18 years ago #

1 – .7 – .3 = 5.55111512 × 10-17

Brian M. [PersonRank 10]

18 years ago #

It can do the equivalent

1 – (1 * .10) – (1 * .90)

sebah [PersonRank 1]

18 years ago #

using ',' instead of dot it works
http://www.google.com/search?hl=pl&q=1+-+0%2C1-0%2C9&btnG=Szukaj&lr=

Mustapha [PersonRank 0]

18 years ago #

Some foating point numbers cannot be represented (in the IEEE 754 standard) in a finite amount of space. Therefore, these numbers are rounded down by approximately -2.78E-17 when they are stored. So, this has noting todo with google.
For more info: http://blog.mustap.com/2005_12_12_google-cant-substract

Philipp Lenssen [PersonRank 10]

18 years ago #

I know they use cheap commodity PCs, so maybe they stacked up on those flawed Intel CPUs from years ago :)

/pd [PersonRank 10]

18 years ago #

I think its a floating point issue at the cpu level. The dx register is true 16bit with a near call within the same stack will produce 32byte words. If its a long call. Then you will be returned 256byte words.

I think if you write the same formula in excel and then format in sci expo , you may get the same results. When back at a desktop level , I am going to try this. If it works, then googs is running a bluwefe farm of pc's for this service.

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