= 3 1 4 1 5 9
1 0 0 0 0 0
0 1 0 1 0 0
0 0 1 0 0 0
0 0 0 0 1 0
0 0 0 0 0 1
   = \: 3 1 4 1 5 9
1 0 0 0 0 0
0 1 0 0 0 0
0 0 1 0 0 0
0 0 0 1 0 0
0 0 0 0 1 0
0 0 0 0 0 1

/: would also have worked.



On Wed, Feb 26, 2014 at 10:36 PM, Michal Wallace
<[email protected]>wrote:

> What purpose does the \: serve there?
>
>    (*=) 9 7 5 3
>
> 9 0 0 0
>
> 0 7 0 0
>
> 0 0 5 0
>
> 0 0 0 3
>
>
>
>
> On Wed, Feb 26, 2014 at 11:48 PM, J. Patrick Harrington
> <[email protected]>wrote:
>
> > even shorter:
> >
> >   diag4=: *=@\:
> >
> >   diag4 9 7 5 3
> > 9 0 0 0
> > 0 7 0 0
> > 0 0 5 0
> > 0 0 0 3
> >               Patrick
> >
> >
> > On Wed, 26 Feb 2014, km wrote:
> >
> >>    (*"0 1 =@i.@#) 1 2 3
> >> 1 0 0
> >> 0 2 0
> >> 0 0 3
> >>
> >> --Kip Murray
> >>
> >> Sent from my iPad
> >>
> >>  On Feb 26, 2014, at 9:35 PM, Roger Hui <[email protected]>
> >>> wrote:
> >>>
> >>>   diag=: 3 : 'y (,&.>~i.#y)} 0 $~ ,~#y'
> >>>   diag 10 20 30 40
> >>> 10  0  0  0
> >>> 0 20  0  0
> >>> 0  0 30  0
> >>> 0  0  0 40
> >>>
> >>>   diag1=: ]\ * =/~@i.@#
> >>>   diag1 10 20 30 40
> >>> 10  0  0  0
> >>> 0 20  0  0
> >>> 0  0 30  0
> >>> 0  0  0 40
> >>>
> >>>   diag2=: -@>:@i.@# {."0 ]
> >>>   diag2 10 20 30 40
> >>> 10  0  0  0
> >>> 0 20  0  0
> >>> 0  0 30  0
> >>> 0  0  0 40
> >>>
> >>>   diag3=: ,~@# $ ] #~ 1 j. #
> >>>   diag3 10 20 30 40
> >>> 10  0  0  0
> >>> 0 20  0  0
> >>> 0  0 30  0
> >>> 0  0  0 40
> >>>
> >>>
> >>>
> >>>
> >>>
> >>>  On Wed, Feb 26, 2014 at 7:12 PM, Joe Bogner <[email protected]>
> >>>> wrote:
> >>>>
> >>>> Sorry, I figured it out:
> >>>>
> >>>> I just needed one more 0...
> >>>>
> >>>>   ]  S * (4 4 $  1 0 0 0 0)
> >>>> 4 0       0 0
> >>>> 0 3       0 0
> >>>> 0 0 2.23607 0
> >>>> 0 0       0 0
> >>>>
> >>>>  On Wed, Feb 26, 2014 at 10:02 PM, Joe Bogner <[email protected]>
> >>>>> wrote:
> >>>>> I'm experimenting with svd and am looking for a nicer way of creating
> >>>>> a matrix from the S diagonal
> >>>>>
> >>>>> 4 3 2.23607 0
> >>>>>
> >>>>> needs to be
> >>>>>
> >>>>> ]   (4 4 $ 4 0 0 0 0 3 0 0 0 0 2.23607  0 0 0 0 0 )
> >>>>> 4 0       0 0
> >>>>> 0 3       0 0
> >>>>> 0 0 2.23607 0
> >>>>> 0 0       0 0
> >>>>>
> >>>>> What would be the idiomatic way to make that conversion? I tried
> >>>>> various versions of reshape and insert.
> >>>>>
> >>>>> Not quite...
> >>>>>
> >>>>> ],\ S
> >>>>> 4 0       0 0
> >>>>> 4 3       0 0
> >>>>> 4 3 2.23607 0
> >>>>> 4 3 2.23607 0
> >>>>>
> >>>>> I also thought about multiplying it by a diagonal matrix of 0s and 1s
> >>>>> but couldn't get that figured out either
> >>>>>
> >>>>> Thanks
> >>>>> Joe
> >>>>>
> >>>> ----------------------------------------------------------------------
> >>>> For information about J forums see
> http://www.jsoftware.com/forums.htm
> >>>>
> >>> ----------------------------------------------------------------------
> >>> For information about J forums see http://www.jsoftware.com/forums.htm
> >>>
> >> ----------------------------------------------------------------------
> >> For information about J forums see http://www.jsoftware.com/forums.htm
> >>
> >>  ----------------------------------------------------------------------
> > For information about J forums see http://www.jsoftware.com/forums.htm
> >
> ----------------------------------------------------------------------
> For information about J forums see http://www.jsoftware.com/forums.htm
>
----------------------------------------------------------------------
For information about J forums see http://www.jsoftware.com/forums.htm

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