--On 9 décembre 2012 18:03:04 -0500 Raul Miller
wrote:
Have you considered writing python code to build files with regular
format?
Yes, but that's a lot of overhead, both in terms of conversion code to
write and in terms of added steps in deployment. I believe I am better off
doing everythi
((+.|.)@={"0 1 ' '&,.)'abcde'
a a
b b
c
d d
e e
On 10-12-12 03:42, km wrote:
Write verb cross.
cross 'abcde'
a a
b b
c
d d
e e
(Result should look like a cross with 'abcde' along both diagonals.)
cross 'a'
a
cross 'ab'
aa
bb
Kip Mur
On 10 December 2012 02:10, William Tanksley, Jr wrote:
> Every notation has problems. If you don't see them, it's not because
> they're not there. It's enormously ironic that you're denying ALL
> problems with "traditional notation"
I am perfectly aware that every notation has problems, and I hav
cross=: ((>: * (+. |.)@:=)@:i.@:# { ({.~ (_1-#)))
cross ;/'abcde'
+-+-+-+-+-+
|a| | | |a|
+-+-+-+-+-+
| |b| |b| |
+-+-+-+-+-+
| | |c| | |
+-+-+-+-+-+
| |d| |d| |
+-+-+-+-+-+
|e| | | |e|
+-+-+-+-+-+
cross 5 43 2
5 0 5
0 43 0
2 0 2
Date: Sun
Numbers, too!
Linda
-Original Message-
From: programming-boun...@forums.jsoftware.com
[mailto:programming-boun...@forums.jsoftware.com] On Behalf Of David Ward
Lambert
Sent: Monday, December 10, 2012 9:32 AM
To: programming
Subject: Re: [Jprogramming] Just for fun, verb cross
cross=:
On Sun, Dec 9, 2012 at 5:01 PM, Boyko Bantchev wrote:
> I also know many people who teach mathematics or informatics at
> school, at different places and certainly to students with average
> (or below) mathematical abilities. My wife has been a school teacher
> in mathematics for years. Neither
Changing the thread.
No. This is a way to check one's work in deriving a proof. And it is not
too difficult to convert the tacit expression to explicit then make the
proof. See example below. Interesting that you chose a monadic test. Tacit
verb phrases are ambivalent. Therefore there must be two
Yes... proofs are a topic that require some thought.
In J, I would usually do a proof as a sequence of statements that I
expect are all tautologies and where each sentence involves only a
minor changes from previous/next statements.
And, I would expect the reader to be verifying that they were ha
As for using J to teach students (presumably we're talking about elementary
to high-school level), I think my exposure to APL in junior high-school
(age 13) helped me better understand matrix math concepts when they were
introduced in high-school.
On Mon, Dec 10, 2012 at 10:21 AM, Raul Miller wr
1e308 ((+*-) -: (-&*:)) 1e308
NaN error
1e308((+*-)-:(-&*:))1e308
- Original Message -
From: "Don Guinn"
To:
Sent: Monday, December 10, 2012 3:57 PM
Subject: Re: [Jprogramming] Proofs in J
Changing the thread.
No. This is a way to check one's work in deriving a proof. And
You can convert to a single dyadic proof with (the well known, I'm
ensuring)
verb~~
> From: Don Guinn
> To: programm...@jsoftware.com
> Subject: Re: [Jprogramming] Proofs in J
> Message-ID:
>
> Content-Type: text/plain; charset=UTF-8
>
> Changing the thread.
>
> No. This is a way t
If we are going to argue J v Python, we need to at least look at NumPy
(based in part on APL) and SciPy. If anybody is interested, I can
start those topics.
I also have another set of issues, regarding choice of languages in
working with Sugar education software. I will give the background
here, a
That is lovely Arie,
It is that kind of elegance that I was chasing with my rougher attempts.
Using the (+.|.) hook simplifies (|.+.]) precisely and the {" 0 1 combined
with ' '&,. means that the selection of the string becomes a choice in each row
of displaying either the corresponding eleme
The expression fails if the argument has duplicate items. e.g.
((+.|.)@={"0 1 ' '&,.)'aabbb'
|length error
| ((+.|.)@={"0 1' '&,.)'aabbb'
On Mon, Dec 10, 2012 at 10:18 AM, bob therriault wrote:
> That is lovely Arie,
>
> It is that kind of elegance that I was chasing with my rougher a
I would be interested in NumPy.
I have to use python in some contexts, but I have not had the time to
study all the options, and on my own it would take me years to get up
to speed on something like NumPy.
As for the rest of your message: I will agree with you on the need for
a variety of perspec
Here's a version that works with duplicated values (except note that
there was no specification for what the behavior should be in this
case):
(,@(#~"0"1) (+.|.)@=)'abcde'
a e
b d
c
b d
a e
(,@(#~"0"1) (+.|.)@=)'abcdedcba'
a e a
b d d b
c c
b d d b
a e a
--
Raul
On
Thanks for destroying my day.
Here's a much longer alternative
' ' (,{~[:((+.|.)@= ({"0 1) 0&,.) 1+i.@#@]) 'baabb'
b b
a a
a
b b
b b
_ (,{~ [: ((+.|.)@=({"0 1) 0&,.) 1+i.@#@]) 1 2 1 2
1 _ _ 1
_ 2 2 _
_ 1 1 _
2 _ _ 2
On 10-12-12 19:21, Roger Hui wrote:
The expression fails if
Thanks Roger,
I guess this is why we race Ferrari's and go shopping in minivans. :)
My first draft survives repeats, but I still find Arie's version beautiful (and
functional within the specs of not having repeated items).
t0=:((>.|."1)@(*=)@:>:@i.@#){ ' ',]
t0 'abcde'
a a
b b
c
Ugly as hell (but my J doesn't get any better without practicing):
cross =.(((1 {. 0 # ]), ]) {~ (>:*(|.+.])@(=/~))@i.@#)
NB. Works for strings with replicated entries
cross 'aabbcdeabcde'
aa
b b
cc
d d
ee
aa
b b
cc
On 10 December 2012 17:21, Raul Miller wrote:
>
> Hopefully my few minutes of effort here have done something to rectify
> this gap in this part of your knowledge?
You would have spent your time more fruitfully – and saved mine –
had you actually read what you are posting, rather tha
((+*-) -: (-&*:))~ 10x^308
1
But mine goes to eleven:
((+*-) -: (-&*:))~ 11x^308
1
On Mon, Dec 10, 2012 at 12:46 PM, Roger Stokes <
r...@rogerstokes.free-online.co.uk> wrote:
> 1e308 ((+*-) -: (-&*:)) 1e308
> NaN error
> 1e308((+*-)-:(-&*:))1e308
>
>
> - Original Message -
And, for what it's worth, here's a different plausible implementation
of cross (different only for the case of duplicated letters in the
argument when compared with the version I posted, below):
(,@(#~"0"1) (+.|.)@=@(#\)) 'abcdedcba'
Note that replacing = with =@(#\) should also work for Aai's
Boyko, the discussion is futile whenyou do not believe that I am serious. But
note that the expression mc² has the dimension of energy. The expression
cm² (= 1cm²) has the dimension of area. Neither of these expressions evaluate
into a dimensionless number.
- Bo
>__
For what it's worth, here's a parenthesis free implementation of my
two variant definitions of cross (and note that I am using what is
probably an unfamiliar J idiom here -- please feel free to ask for an
explanation, if I am not making sense):
selch=: #"0"1
orflp=: +.|.@
cross1=: ,@selch~ = orflp
My solution works by preparing a left argument for From { . It has rank two
solutions and is limited to string arguments.
cross
([: (+. |."1) [: (= * >:) [: i. #) { ' ' , ]
cross 'a'
a a
a a
a
a a
a a
Kip Murray
Sent from my iPad
On Dec 10, 2012, at 1:48 PM, Rau
Without looking studying the sentence evaluator, I expected
+.|.@
(+. |.)@
to be identical to
+.(|.@)
|.@+.
> Date: Mon, 10 Dec 2012 15:41:52 -0500
> From: Raul Miller
> To: programm...@jsoftware.com
> Subject: Re: [Jprogramming] Just for fun, verb cross
> Message-ID:
> +o...@ma
Yes...
The precedence rule for conjunctions is different when no right
argument is provided. In that case, the conjunction has lower
precedence than anything else in the language. It's as if there's a
"free parenthesis" to its left.
In other words
+.|.@
is equivalent to
(+. |.)@
The reas
On Mon, December 10, 2012 1:26 pm, Raul Miller wrote:
> I would be interested in NumPy.
>
> I have to use python in some contexts, but I have not had the time to
> study all the options, and on my own it would take me years to get up
> to speed on something like NumPy.
Start here.
http://docs.sci
Gripes:
The type system seems way too complex -- why should I care in the
typical case, what type of value is used to represent the numeric
value 1? Why can't it give me consistent operations? For example, I
do not like that booleans do not include the value 0 and 1 -- this not
only perpetuates
Is there a better way than the verb `am` to do the
following?
am =:_1& (I.@:-.@]})
am"1] 2 6 ?.@$ 2
_1 _1 _1 _1 1 _1
_1 _1 _1 1 1 _1
(B=)
--
For information about J forums see http://www.jsoftware.com/forums.htm
((+.|.)@={"0 1 ' '&,.)'apple'
|length error
| ((+.|.)@={"0 1' '&,.)'apple'
I think the letters must be in alphabetical order.
Linda
-Original Message-
From: programming-boun...@forums.jsoftware.com
[mailto:programming-boun...@forums.jsoftware.com] On Behalf Of bob
therriault
Sen
Roger's explanation is better than mine.
Linda
-Original Message-
From: programming-boun...@forums.jsoftware.com
[mailto:programming-boun...@forums.jsoftware.com] On Behalf Of Linda Alvord
Sent: Monday, December 10, 2012 7:41 PM
To: programm...@jsoftware.com
Subject: Re: [Jprogramming] Ju
Double the distance between 0 and 1, and then shift those points left one unit
on the number line.
am2=: ((-&1) @ +:)
am2"1] 2 6 ?.@$ 2
_1 _1 _1 _1 1 _1
_1 _1 _1 1 1 _1
Does that make sense?
... peter
Brian Schott wrote:
Is there a better way than
<:@:+: 0 1
_1 1
(_1 + +:)0 1 NB. for Linda
_1 1
> Date: Mon, 10 Dec 2012 19:13:05 -0500 (EST)
> From: Brian Schott
> To: programm...@jsoftware.com
> Subject: [Jprogramming] convert 0,1 coding to _1,1
> Message-ID:
> Content-Type: TEXT/PLAIN; format=flowed; charset=US-ASCII
>
> Is there a
Peter and David,
Thanks. That is a way that I had forgotten and may be preferred.
---
(B=)
On Dec 10, 2012, at 7:13 PM, Brian Schott wrote:
> Is there a better way than the verb `am` to do the following?
>
> am =:_1& (I.@:-.@]})
> am"1] 2 6 ?.@$ 2
> _1 _1 _1 _1 1 _1
> _1 _1 _1 1 1 _1
>
"My way" would even work in Algebra I.
Linda
-Original Message-
From: programming-boun...@forums.jsoftware.com
[mailto:programming-boun...@forums.jsoftware.com] On Behalf Of David Ward
Lambert
Sent: Monday, December 10, 2012 7:58 PM
To: programming
Subject: Re: [Jprogramming] convert 0,1
If you really are converting random boolean values to (1,_1) values,
another possibility is _1&^ or _1^]; i.e. 0 to 1 and 1 to _1.
On Mon, Dec 10, 2012 at 8:58 PM, Brian Schott wrote:
>timespacex
> 6!:2 , 7!:2@]
>am =:_1& (I.@:-.@]})
>am2=: ((-&1) @ +:)
>amd=: <:@:+:
>aml=: _
Also {&_1 1 .
On Mon, Dec 10, 2012 at 11:32 PM, Roger Hui wrote:
> If you really are converting random boolean values to (1,_1) values,
> another possibility is _1&^ or _1^]; i.e. 0 to 1 and 1 to _1.
>
>
>
> On Mon, Dec 10, 2012 at 8:58 PM, Brian Schott wrote:
>
>>timespacex
>> 6!:2 , 7!:2@]
Those are fast and lean, as you can see below.
amr=: _1&^
timespacex 'amr d'
0.002708 8.39027e6
amr1=: {&_1 1
timespacex 'amr1 d'
0.002657 8.39027e6
On Tue, Dec 11, 2012 at 2:39 AM, Roger Hui wrote:
> Also {&_1 1 .
>
>
> On Mon, Dec 10, 2012 at 11:32 PM, Roger Hui wrote:
>
>> If yo
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