Re: Chop in Mathematica 8.0.1
- To: mathgroup at smc.vnet.net
- Subject: [mg117636] Re: Chop in Mathematica 8.0.1
- From: Oliver Ruebenkoenig <ruebenko at wolfram.com>
- Date: Tue, 29 Mar 2011 06:51:09 -0500 (EST)
On Thu, 24 Mar 2011, DrMajorBob wrote: > Intentional or not, I don't like it. why not? > > When I write 1.1 I, I do NOT imply that the real part is also approximate. You can Rationalize Oliver > > Bobby > > On Wed, 23 Mar 2011 02:52:06 -0500, Heike Gramberg > <heike.gramberg at gmail.com> wrote: > >> In the "Possible Issues" section in the documentation of Chop it says >> that >> "Machine complex numbers have machine reals for both real and imaginary >> parts", and that "Consequently, Chop does not make the real part of >> machine complex numbers an exact zero", so I guess it's intentional. >> >> Heike >> >> On 21 Mar 2011, at 11:12, Andrzej Kozlowski wrote: >> >>> Hmm... perhaps this is not a bug but a deliberate new design? >>> >>> Just evaluating >>> >>> 1.1 I >>> >>> returns >>> >>> 0. +1.1 >>> >>> It seems a purely cosmetic issue but it does look a rather >>> "untraditional". Can anyone confirm that this is indeed an intentional >>> change? >>> >>> Andrzej Kozlowski >>> >>> >>> >>> On 20 Mar 2011, at 12:44, Andrzej Kozlowski wrote: >>> >>>> Chop does not seem to work properly in Mathematica 8.0.1: >>>> >>>> f[a_] := 2 I Pi Sin[a]/a >>>> >>>> In[2]:= f[1.] >>>> >>>> Out[2]= 0. + 5.287118128162912*I >>>> >>>> In[3]:= Chop[%] >>>> >>>> Out[3]= 0. + 5.287118128162912*I >>>> >>>> This is with >>>> >>>> In[4]:= $Version >>>> >>>> Out[4]= 8.0 for Mac OS X x86 (64-bit) (February 23, 2011) >>>> >>>> Mathematica 7.01 returns 5.287118128162912*I as expected. >>>> >>>> Can anyone confirm it? At the moment I can't see any simple work >>> around... >>>> >>>> Andrzej Kozlowski >>> >>> >> > > >