Henry Rich wrote:
> It could just be that the poster wanted to see a recursive version ...
Recursive functions have some inherent complexities - to properly
understand them, you need to think about the base case and the
recursive case, but you also have to see how that connects to the idea
as a wh
It could just be that the poster wanted to see a recursive version of
this problem (and one using ^:) so that he could learn how to apply
those methods to other problems that really needed them.
Henry Rich
On 9/29/2017 11:01 PM, Don Kelly wrote:
So it is a game- fair enough- it shows that in J
So it is a game- fair enough- it shows that in J there are more ways
than one to skin a cat. BUT does it really bring out the reason for a
language like J or APL? Does it bring out the power of J to make so many
things simpler and more elegant for the user? You have used APL and so
have I -and
Actually this can be done without loss of precision. I cheat a lot of times
when asked to generate a function that matches a series. If the series is a
polynomial simply solve for the coefficients.
z=.4 9 15 22 30 39 49 60 72 85
z%.(i.#z)^/i.6x
4 9r2 1r2 0 0 0
---
Yes - nice - it's related to the result:
ti = 4i + i(i-1)%2 , discussed in my message,
with t0 = 0,
although you're doing the equivalent of
ti = 4(i+1) + i(i+1)%2, with t0 = 4,
here.
Beware loss of precision on long sequences, though,
as the default datatype is floating, and given all the
Here is another way:
4 4.5 0.5 p. i.10
4 9 15 22 30 39 49 60 72 85
On Fri, Sep 29, 2017 at 3:32 AM, 'Mike Day' via Programming <
programm...@jsoftware.com> wrote:
> Linda offers:
> f=: 13 :'+/"1(>:/~i.y)*(y#x)+/i.y' NB. (msgsbelow)
>
> My best f , with an [: for Linda's sake:
>f =: ([:+/
Linda offers:
f=: 13 :'+/"1(>:/~i.y)*(y#x)+/i.y' NB. (msgsbelow)
My best f , with an [: for Linda's sake:
f =: ([:+/\ (+i.))
4 f 7
4 9 15 22 30 39 49
HOWEVER, although Skip initially asked for a way to render
4, (4+5), (4+5+6), ... recursively, we may consider that
the (i+1)th term may b
Fair enough -he did ask for a recursive form. summing is similar to the
non recursive method for forming "sin" from a series . In other words-
why go to recursive- shades of Basic, Fortran and other languages
needing a loop for this. It is a bit of beating a dead horse.
Don
On 2017-09-28 4
doh!
+/\4+i.10
4 9 15 22 30 39 49 60 72 85
O
f course! I should have seen that.
Actually, I thought that a recursive approach would be simpler/more concise,
but that doesn't seem to be the case.
Skip Cave
Cave Consulting LLC
On Thu, Sep 28, 2017 at 8:57 PM, Linda Alvord
wrote:
> Or:
> f=: 1
Or:
f=: 13 :'+/"1(>:/~i.y)*(y#x)+/i.y'
4 f 7
4 9 15 22 30 39 49
Linda
Sent from AOL Mobile Mail
On Thursday, September 28, 2017 Raul Miller wrote:
Nothing is simpler than the i. approach, but ^: is not significantly more
complex than $: approach: }:(}:,+/@(_2&{.),>:@{:)^:9]4 4 9 15 22 30
Or:
f=: 13 :'+/"1(>:/~i.y)*(y#x)+/i.y'
4 f 7
4 9 15 22 30 39 49
Earlier message from tablet and this from phone.
Linda
Linda
Sent from AOL Mobile Mail
On Thursday, September 28, 2017 Raul Miller wrote:
Nothing is simpler than the i. approach, but ^: is not significantly more
complex t
How about?
f=: 13 :'+/"1(>:/~i.y)*(y#x)+/i.y'
4 f 7
4 9 15 22 30 39 49
Linda
Sent from AOL Mobile Mail
On Thursday, September 28, 2017 Raul Miller wrote:
Nothing is simpler than the i. approach, but ^: is not significantly more
complex than $: approach: }:(}:,+/@(_2&{.),>:@{:)^:9]
'0' -.~ ,'),',"1~ '(',"1 ": +\4+i.10
just add + here and there
On 28 Sep 2017 18:34, "Skip Cave" wrote:
> What is a good way to generate this sequence in J?
>
> 4,(4+5),(4+5+6),(4+5+6+7),(4+5+6+7+8)+.
>
> Show one way using i. and insert.
>
> Show another way using recursion.
>
> Skip
>
>
It's not better. Skip asked for a recursive version too so we gave him
one. Very complicated way to write a simple thing. Lol. /Erling
On 2017-09-29 01:24, Don Kelly wrote:
why is this better than the easy to read version that Roger Hui sent?
quote:
+/\4+i.10
4 9 15 22 30 39 49 60 72 85
why is this better than the easy to read version that Roger Hui sent?
quote:
+/\4+i.10
4 9 15 22 30 39 49 60 72 85
unquote: This is also the way APL does it Sure it is fun to try
different ways such as below, just as it is fun to make a 1 liner to
generate a series for sin x. It is also ni
Nothing is simpler than the i. approach, but ^: is not significantly
more complex than $: approach:
}:(}:,+/@(_2&{.),>:@{:)^:9]4
4 9 15 22 30 39 49 60 72
Thanks,
--
Raul
On Thu, Sep 28, 2017 at 3:37 PM, Xiao-Yong Jin wrote:
>
>
>> On Sep 28, 2017, at 1:40 PM, Raul Miller wrote:
>>
>> Tha
> On Sep 28, 2017, at 2:45 PM, Erling Hellenäs wrote:
>
>4 [`(] (] , [ + [: {: ]) [ $: [: <: ])@.(<) 8
> 4 9 15 22 30
Super!
4 [`(] (] , (+{:)) ($:<:) )@.< 8
> /Erling
>
> On 2017-09-28 20:33, Skip Cave wrote:
>> What is a good way to generate this sequence in J?
>>
>> 4,(4+5),(4+5+6)
4 [`(] (] , [ + [: {: ]) [ $: [: <: ])@.(<) 8
4 9 15 22 30
/Erling
On 2017-09-28 20:33, Skip Cave wrote:
What is a good way to generate this sequence in J?
4,(4+5),(4+5+6),(4+5+6+7),(4+5+6+7+8)+.
Show one way using i. and insert.
Show another way using recursion.
Skip
Skip Cave
Cav
> On Sep 28, 2017, at 2:37 PM, Xiao-Yong Jin wrote:
>
>
>
>> On Sep 28, 2017, at 1:40 PM, Raul Miller wrote:
>>
>> That is what I would assume:
>>
>> 4,(4+5),(4+5+6),(4+5+6+7),(4+5+6+7+8)
>> 4 9 15 22 30
>>
>> I was trying to figure out a recursive approach which isn't vastly
>> more ted
> On Sep 28, 2017, at 1:40 PM, Raul Miller wrote:
>
> That is what I would assume:
>
> 4,(4+5),(4+5+6),(4+5+6+7),(4+5+6+7+8)
> 4 9 15 22 30
>
> I was trying to figure out a recursive approach which isn't vastly
> more tedious...
4( [, +( ([,+)`$:@.(10>]) ) >:@])5
On the other hand, ^: can
That is what I would assume:
4,(4+5),(4+5+6),(4+5+6+7),(4+5+6+7+8)
4 9 15 22 30
I was trying to figure out a recursive approach which isn't vastly
more tedious...
Thanks,
--
Raul
On Thu, Sep 28, 2017 at 2:39 PM, Roger Hui wrote:
> You don't mean
>
>+/\4+i.10
> 4 9 15 22 30 39 49 60 7
You don't mean
+/\4+i.10
4 9 15 22 30 39 49 60 72 85
do you?
On Thu, Sep 28, 2017 at 11:33 AM, Skip Cave wrote:
> What is a good way to generate this sequence in J?
>
> 4,(4+5),(4+5+6),(4+5+6+7),(4+5+6+7+8)+.
>
> Show one way using i. and insert.
>
> Show another way using recursion.
What is a good way to generate this sequence in J?
4,(4+5),(4+5+6),(4+5+6+7),(4+5+6+7+8)+.
Show one way using i. and insert.
Show another way using recursion.
Skip
Skip Cave
Cave Consulting LLC
--
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