[Jprogramming] Difference between 5^100x and x: 5^100

[Dan Bron]

I wrote:
> I don't understand 

Regarding your comment:
>   dd ,:1 2  NB. The result exceeds  ":
> 1+i.1 2 

Ah, I see.  You're saying  (dd >&# ":) ,: 1 2  .  Well, keep two things in mind:

   (A)  For large arguments,  dd  will either dramatically beat or tie with  ":  .  For small arguments, the differences will be
minute and probably overshadowed by the mechanism of communication [1].  Take my example where two J servers are connected via
sockets for this case:  Nagel's algorithm (and the size of a TCP/IP packet) virtually guaruntee neither message will arrive sooner
[1].   Which brings me to my second point.

   (B)  These two verbs do different things.  The point of my J IPC protocol was to send data from one J session to another, such
that the receiving J server received an exact copy of the noun sent by the sending J server.  Now note:

	   (-: ".@:":) ,: 1
	0
	   (-: ".@:dd) ,: 1
	1

the result of  ".":y  is not guarunteed to be the same as  y  (for the reasons discussed elsewhere in this thread).  Which just
means we're not really comparing apples-to-apples in the first place.

And, in the interests of full disclosure, I will note that while our initial J IPC protocol leveraged this feature of  5!:5  , we
changed it in a later release to use  3!:1  .  The cost of sending large nouns when  5!:5  couldn't find a terse J expression
which resulted in that noun far outstripped the gains from the cases where it could.  

-Dan