> School math is accurate, there are no approximations at all. Neither > binary nor decimal are accurate, both will violate people's > expectations of accuracy. If you do (1.0 / 3.0) * 3.0 neither binary > nor decimal give you 1.0.
D'oh! I just tried this and it actually gives 1.0 using both 32-bit and 64-bit binary arithmetic. But it's easy to construct examples where none of the systems are accurate, for instance x = 2/3 print((0.5 + x) - x); This gives, depending on which arithmetic system you use: 128-bit decimal: 0.5000000000000000000000000000000003 64-bit binary: 0.4999999999999999 64-bit decimal: 0.5000000000000003 32-bit binary: 0.50000006 Using school math you would expect that adding and then subtracting the same number would get you back where you started. Decimal is a counter-intuitive as binary in that respect. _______________________________________________ es-discuss mailing list es-discuss@mozilla.org https://mail.mozilla.org/listinfo/es-discuss
