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Re: Re: Re: A Sum-like notation for iteration

  • To: mathgroup at smc.vnet.net
  • Subject: [mg102463] Re: [mg102422] Re: [mg102415] Re: A Sum-like notation for iteration
  • From: DrMajorBob <btreat1 at austin.rr.com>
  • Date: Mon, 10 Aug 2009 04:14:56 -0400 (EDT)
  • References: <h5bk7g$hn3$1@smc.vnet.net> <h5ebii$1rc$1@smc.vnet.net>
  • Reply-to: drmajorbob at bigfoot.com

David,

Now that you've started it, you might like something my mother sent me 35  
years or so ago.

Titled (I think) "The Brontosaurus"

Behold the mighty dinosaur,
Famous in prehistoric lore,
Not only for his power and strength
But for his intellectual length.
You will observe by his remains
The creature had two sets of brains ---
One in his head (the usual place),
The other at his spinal base.
Thus he could reason a priori
As well as a posteriori.
No problem bothered him a bit;
He made both head and tail of it.
So wise was he, so wise and solemn,
Each thought filled just a spinal column.
If one brain found the pressure strong,
It passed a few ideas along.
If something slipped his forward mind,
'Twas rescued by the one behind.
And if in error he was caught,
He had a saving afterthought.
As he thought twice before he spoke,
He had no judgment to revoke.
Thus he could think without congestion
Upon both sides of every question.
Oh, gaze upon this model beast,
Defunct ten million years at least.

-- Bert L. Taylor of the Chicago Tribune


Bobby

On Sun, 09 Aug 2009 05:03:38 -0500, David Park <djmpark at comcast.net> wrote:

> One possibility is to use ellipsis notation from Presentations.
>
> iTable[f[x], {x, 1, 3, , 99}]
>
> {f[1],f[3],\[CenterEllipsis],f[99]}
>
> Generalizing the second case somewhat:
>
> iTable[f[Subscript[x, i]], {i, 1, 2, , n}, tag1]
> % // iTableNormalize[tag1, {Subscript[x, i], {3, 1, 100, Sin[2]}}]
>
> {f[Subscript[x, 1]],f[Subscript[x, 2]],\[CenterEllipsis],f[Subscript[x,  
> n]]}
>
> {f[3], f[1], f[100], f[Sin[2]]}
>
> Ellipsis expressions are common mathematical notations and mathematicians
> are pretty quick to spot the patterns. But they certainly aren't a  
> universal
> solution.
>
> By the way, T-Rex had a brain both in his head, and a smaller brain in  
> his
> tail. He was thus able to reason both a priori and a posteriori.
>
>
> David Park
> djmpark at comcast.net
> http://home.comcast.net/~djmpark/
>
>
> From: magma [mailto:maderri2 at gmail.com]
>
>
> Quote: how do we format something like Table[f[x], {x, 1, 100, 2}]?
> Or,
> worse, Table[f[x], {x, {1,2,3,4,5}}]? Whatever solution is chosen, the
> point is that it is no longer "intuitive", at least not in the sense
> that one could readily guess what it should look like.
>
>
>
>
>



-- 
DrMajorBob at bigfoot.com


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