Your analysis is almost right. Actually, {."1 benefits
from Integrated Rank Support, which means that the
loop over the operand is a tight inner loop rather than
starting the whole verb up anew for each 1-cell.
So, [EMAIL PROTECTED] starts {. and +. for each 0-cell, while
{."1@:+. starts +. once and {. once.
Henry Rich
> -----Original Message-----
> From: [EMAIL PROTECTED]
> [mailto:[EMAIL PROTECTED] On Behalf Of
> Graham Parkhouse
> Sent: Monday, January 08, 2007 12:05 PM
> To: [email protected]
> Subject: [Jprogramming] RE: Why won't this plot?
>
> Henry wrote
>
> >> [EMAIL PROTECTED] Applied in this situation is a nice example of the
> >> usefulness of @ .
> >
> >If you're going to use this much, use
> >
> >{."1@:+.
> >
> >which is quite a bit faster. It's a good exercise for you
> >to learn why, too.
> >
> >Henry Rich
>
> ([EMAIL PROTECTED])b. 0
> 0 0 0
> ({."1@:+.)b. 0
> _ _ _
>
> Above is the difference between @ and @:
>
> Am I right in thinking that the first function performs +.
> followed by {. on
> every atom of the argument iteratively, while the second
> performs +. on the
> whole argument (which is more efficient) but then does the "1
> operation
> iteratively (no more efficiently then the first function)?
>
> Thank you, John, for the link -- this is not a new problem.
> But Roger did
> recognise it as a bug.
>
> Graham Parkhouse
>
>
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