Sorry for answering so late.
I'm basing everything I say on rank as it's interpreted in J.
The rank of an array is the number of dimensions it has.
A scalar has rank 0, a vector 1, matrix 2, cube 3, etc.
If an array has the shape 3 1 4 1 5 9, then it can be
"decomposed" into a frame and cells: it
Actually Dyalog returns the same result.
Elias Mårtenson writes:
> In GNU APL, the following two expressions yield the same result:
>
> (+/⍤1) 3 4⍴⍳100
> ┏→━━━┓
> ┃10 26 42┃
> ┗┛
>
> And:
>
> (+/⍤¯1) 3 4⍴⍳100
> ┏→━━━┓
> ┃10 26 42┃
> ┗┛
>
> I would expect the latter to yie
TryAPL is powered by Dyalog APL and shows the same results as GNU APL
on the neg one case, as below:
http://tryapl.org/#?a=%28+/%u2364%AF1%293%204%u2374%u2373100&run
Ala'a
Hi Elias,
the ISO standard (taking the monadic case for simplicity) says:
Z ← f ⍣ y B
...
If y is a scalar, set y1 to ,y. Otherwise set y1 to y.
If y1 is not a vector, signal domain-error.
If y1 has more than three elements, signal lengt
In GNU APL, the following two expressions yield the same result:
* (+/⍤1) 3 4⍴⍳100*
┏→━━━┓
┃10 26 42┃
┗┛
And:
* (+/⍤¯1) 3 4⍴⍳100*
┏→━━━┓
┃10 26 42┃
┗┛
I would expect the latter to yield the following (which is what I believe
Dyalog does):
┏→━━┓
┃15 18
On 6 May 2016 at 13:52, Juergen Sauermann wrote:
> Except maybe for the Dyalog ¯1 case (primarily because I don't know what
> "major cells" are).
Dyalog treats ¯1 the same as the ISO standard (and therefore also GNU
APL). "Major cell" is explained on page 14 of:
http://docs.dyalog.com/14.1/Dyalog
Hi,
after reading both the ISO standard and the Dyalog definition of ⍤
several times,
it seems to me as if they all describe the same thing (in different
ways).
Except maybe for the Dyalog ¯1 case (primarily because I don't know
what "major cells" are).
Hi,
Here is the definition
http://help.dyalog.com/14.1/Content/Language/Primitive%20Operators/Rank.htm
Juergen Sauermann writes:
> Hi Louis,
>
> just for curiosity, where are negative ranks defined?
> My version of "Mastering Dyalog APL" (ISBN : 978-0-9564638-0-7) does
> not even mention the ra
Hi Louis,
just for curiosity, where are negative ranks defined?
My version of "Mastering Dyalog APL" (ISBN : 978-0-9564638-0-7)
does
not even mention the rank operator.
/// Jürgen
On 04/28/2016 12:31 AM, Louis de
Fo
Whoops. Looks like I got here too late.
Well done!
Louis
> On 28 Apr 2016, at 00:29, Louis de Forcrand wrote:
>
> The three-item form is used if the associated function is ambivalent (applied
> to the P-cells of ⍵ if monadic, applied to corresponding Q-cells of ⍺ and
> R-cells of ⍵ if dyadic)
The three-item form is used if the associated function is ambivalent (applied
to the P-cells of ⍵ if monadic, applied to corresponding Q-cells of ⍺ and
R-cells of ⍵ if dyadic). I don't believe it is possible to define ambivalent
functions in ISO APL however, so it is kind of redundant. It is pro
Incidentally, it works like this in Dyalog and NARS2000 too, though
the Dyalog documentation doesn't mention the 3-item form.
Jay.
On 27 April 2016 at 09:02, Jay Foad wrote:
> Given g ← f⍤P Q R:
> P is the monadic rank
> Q is the left rank
> R is the right rank
>
> So:
> g Y applies g to the P-c
Thanks, that's interesting.
However, I'm still a big confused about the 3-value case. When is P, Q and
R all used?
Secondly, do you agree that that negative ranks would be useful?
Regards,
Elias
On 27 April 2016 at 16:02, Jay Foad wrote:
> You're reading section 9.3.4 "Rank operator deriving
You're reading section 9.3.4 "Rank operator deriving monadic
function". You also need to look at 9.3.5 "Rank operator deriving
dyadic function".
Given g ← f⍤P Q R:
P is the monadic rank
Q is the left rank
R is the right rank
So:
g Y applies g to the P-cells of Y
X g Y applies g to the Q-cells of
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