(|:O)&({"1)&.|:"2 F
is a little faster and leaner on my machine,
but I like the others better.
Henry Rich
> -----Original Message-----
> From: [EMAIL PROTECTED]
> [mailto:[EMAIL PROTECTED] On Behalf Of R.E. Boss
> Sent: Sunday, November 12, 2006 7:39 AM
> To: 'General forum'
> Subject: RE: [Jgeneral] selection expression in J
>
> Efficiency or elegance, that's the question.
>
> O=: 300 5 [EMAIL PROTECTED] 7
> F=: 11000 7 5 [EMAIL PROTECTED] 1000
>
> ts'O{"1&.|:"2 F'
> 0.56605679 67155008
>
> ts'O{"1"2&.:(|:"2) F'
> 0.4679156 1.3422016e8
>
> R.E. Boss
>
>
> -----Oorspronkelijk bericht-----
> Van: [EMAIL PROTECTED]
> [mailto:[EMAIL PROTECTED]
> Namens Henry Rich
> Verzonden: zaterdag 11 november 2006 23:42
> Aan: 'General forum'
> Onderwerp: RE: [Jgeneral] selection expression in J
>
> I think that O{"1&.|:"2 F is transposing O for
> each item of F, in which case better would be
>
> O{"1"2&.:(|:"2) F
>
> Henry Rich
>
> > -----Original Message-----
> > From: [EMAIL PROTECTED]
> > [mailto:[EMAIL PROTECTED] On Behalf Of R.E. Boss
> > Sent: Friday, November 10, 2006 2:09 PM
> > To: 'General forum'
> > Subject: RE: [Jgeneral] selection expression in J
> >
> > This is the most elegant I can come up with
> >
> > $O{"1&.|:"2 F
> > 11 3 5
> >
> > X-:O{"1&.|:"2 F
> > 1
> >
> > It was hidden in what Brouwer wrote before:
> > > I tried the following and it works
> > > 1|:(|:O)(({" 1 )" 2) 1|:F
> >
> > R.E. Boss
> >
> >
> > -----Oorspronkelijk bericht-----
> > Van: [EMAIL PROTECTED]
> > [mailto:[EMAIL PROTECTED]
> > Namens Roger Hui
> > Verzonden: vrijdag 10 november 2006 19:06
> > Aan: General forum
> > Onderwerp: Re: [Jgeneral] selection expression in J
> >
> > Alternative solutions:
> >
> > X=: (<_2 _1) |: O {"2 F
> > X -: O 4 : 'x}y'"1 2"2 F
> > 1
> > X -: (O ,&.>"1 i.{:$O) {"2 F
> > 1
> >
> >
> >
> > ----- Original Message -----
> > From: Roger Hui <[EMAIL PROTECTED]>
> > Date: Friday, November 10, 2006 3:14 am
> > Subject: Re: [Jgeneral] selection expression in J
> >
> > > O=: 3 5 [EMAIL PROTECTED] 7
> > > F=: 11 7 5 [EMAIL PROTECTED] 1000
> > > $ O {"2 F
> > > 11 3 5 5
> > > $ (<_2 _1) |: O {"2 F
> > > 11 3 5
> > >
> > >
> > >
> > > ----- Original Message -----
> > > From: "Brouwer, Roelof <[EMAIL PROTECTED]>" <[EMAIL PROTECTED]>
> > > Date: Friday, November 10, 2006 2:26 am
> > > Subject: RE: [Jgeneral] selection expression in J
> > >
> > > > The following would work if the first axis of X and F was not
> > > > there. But
> > > > even in the 2 axis case there might be a more elegant
> expression
> > > > withouthaving to do so many tranposes
> > > > X=.|:(|:O){"1 |:F
> > >
> > >
> > >
> > >
> > > > -----Original Message-----
> > > > From: [EMAIL PROTECTED]
> > > > [EMAIL PROTECTED] On Behalf Of Henry Rich
> > > > Sent: November 10, 2006 12:12 PM
> > > > To: 'General forum'
> > > > Subject: RE: [Jgeneral] selection expression in J
> > > >
> > > > x =: ((<s,((<p,a){O),a) { F) (<s,p,a)} x
> > > >
> > > > is a direct translation of what you wrote. Is that
> > > > what you want?
> > >
> > >
> > >
> > > > > -----Original Message-----
> > > > > From: [EMAIL PROTECTED]
> > > > > [EMAIL PROTECTED] On Behalf Of Brouwer,
> > > > > Roelof <[EMAIL PROTECTED]>
> > > > > Sent: Friday, November 10, 2006 4:27 AM
> > > > > To: General forum
> > > > > Subject: [Jgeneral] selection expression in J
> > > > >
> > > > > If I want
> > > > >
> > > > >
> > > > >
> > > > > X(s,p,a)<- F(s,O(p,a),a) s=0..ns-1 p=0..np-1 a=0..na-1
> > > > > O is np
> > > > > by na and O 's components have values 0..nv-1 ; F is ns
> > > > > by nv by na
> > > > > ; and X is ns by np by na
> > > > >
> > > > >
> > > > >
> > > > > What is an elegant J expression that will do the trick
> >
> >
> >
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