[Jprogramming] Unexpected size of noun

[Roger Hui]

J allocates memory in chunks of size a power of 2.



On Wed, Jan 11, 2012 at 12:07 PM, Devon McCormick <devonmcc at gmail.com>wrote:

> Well, that would explain a factor of 2 difference but not the factor of 2.5
> that I observe.
>
> On Wed, Jan 11, 2012 at 2:44 PM, David Mitchell <davidmitchell at att.net
> >wrote:
>
> > The size of integer is 8 bytes in 64 bit J.
> >
> > On 1/11/2012 14:42, Devon McCormick wrote:
> > > Can anyone explain why this variable is much larger than it ought to
> be?
> > > Are integers more than 4 bytes in 64-bit J7?
> > >
> > >     $RH5
> > > 2598960 5
> > >     3!:0 RH5    NB. is integer
> > > 4
> > >     */4,$RH5   NB. Should be about this big
> > > 51979200
> > >     7!:5<'RH5'  NB. but this seems far too large, even if there's some
> > > overhead.
> > > 1.3421773e8
> > >     (7!:5<'RH5') % */4,$RH5
> > > 2.582143
> > >
> > >     JVERSION
> > > Engine: j701/2011-01-10/11:25
> > > Library: 7.01.052
> > > Platform: Win 64
> > > Installer: j701a_win64.exe
> > > InstallPath: c:/program files (x86)/j64-701
>