Re: Mod and QuotientRemainder are inconsistent

*To*: mathgroup at smc.vnet.net*Subject*: [mg124885] Re: Mod and QuotientRemainder are inconsistent*From*: Bob Hanlon <hanlonr357 at gmail.com>*Date*: Fri, 10 Feb 2012 05:58:31 -0500 (EST)*Delivered-to*: l-mathgroup@mail-archive0.wolfram.com*References*: <201202091035.FAA18248@smc.vnet.net>

To get exact results use exact numbers Mod[12, 1/10] 0 Mod[12, Rationalize[0.1]] 0 Bob Hanlon On Thu, Feb 9, 2012 at 5:35 AM, Szabolcs <szhorvat at gmail.com> wrote: > > Mod[12, 0.1] gives 0.1 despite 120*0.1 == 12. I expect this is because 0.1 is not representable in binary. > > QuotientRemainder[12, 0.1] gives {120, 0.} however, which is inconsistent with the result above. > > Quotient[12,0.1] gives 120 which is also inconsistent with Mod. > > Is this a bug or is it by design? It seems it is not safe to assume that > > QuotientRemainder[a,b] == {Quotient[a,b], Mod[a,b]} > > or that > > Quotient[a,b]*b + Mod[a,b] == a >

**References**:**Mod and QuotientRemainder are inconsistent***From:*Szabolcs <szhorvat@gmail.com>