The prospects for more efficient computation improves if you say
name=: x u@:{`[`]} name NB. (0)
name=: x u`[`]} name NB. (1)
instead of
name=: x reverse amend name NB. (2)
name=: x |.@:{ amend name NB. (3)
It is easier and more productive for the prospective special
code to handle (0) and (1) than (2) or (3).
----- Original Message -----
From: greg heil <[EMAIL PROTECTED]>
Date: Wednesday, July 12, 2006 1:15 pm
Subject: Re: [Jprogramming] special coding for stack operations
> On 7/12/06, R&S HUI <[EMAIL PROTECTED]> wrote:
> > What exactly is "swap"? Is it name=: (<i,j) C. name ?
>
> In this context it is as
>
> On 7/12/06, Miller, Raul D <[EMAIL PROTECTED]> wrote:
> > Using the right hand edge of a list as top of stack:
> > swap=: _2 (}. , |[EMAIL PROTECTED]) ]
>
> However it is interesting you asked, as i have been trying to develop
> an efficient generalization, which i have been calling swap, that
> reverses arbitrary elements in an array. Eg defined as
>
> reverse=:[:|.{ NB. reverse of x{y
> amend=: 1 : 'u`[`]}' NB. amend x{y with u of x{y
> swapG=: reverse amend
> (1 2; 2 0) swapG i.4 4
> 0 1 2 3
> 4 5 8 7
> 6 9 10 11
> 12 13 14 15
>
> But i am not clear on how to make this operation efficient, it is
> currently a major fraction of the time budget for my application...
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