In Elton Wang's implementation, I can see one trivial change that might help:
+/+/+/(57=x+/y+/z)*x/y*y/z
Where x=.y=.z=i.29
could instead use
+/,(57=x+/y+/z)*x/y*y/z
Oh yes, good point.
Is there a way to test resource (cpu, mem, time) usage within J?
or, if you prefer
Hi everyone,
I was trying to take 9 boxes and multiply them all together, storing the
output in a single box. The first of the 9 boxes contains 12 numbers, the
second contains 11, and so on, so that the output of this calculation will
be a single box with 12*11*10*9*8*7*6*5*4=79,833,600 numbers.
The OS must indeed supply the memory used by J and it's up to the OS
to decide whether it can do so or not. Memory fragmentation can be an
issue - rebooting might help the OS here, in some cases. Another issue
is virtual memory (swapping to disk, and how that has been
implemented).
That said,
Can you post your commands? It would be an interesting exercise trying to
optimize for performance.
-Dan
Please excuse typos; composed on a handheld device.
On May 26, 2013, at 10:26 AM, Jeremy Smith actuaryjeremysm...@gmail.com wrote:
Hi everyone,
I was trying to take 9 boxes and
Out of memory errors are notoriously hard to debug; if you need to run this
program on any different data than what you're using now I'd take up the
offer to come up with an alternate approach.
By the way, it's common for different oses to display different behavior
under pressure. Windows fails
-Original Message-
From: programming-boun...@forums.jsoftware.com
[mailto:programming-boun...@forums.jsoftware.com] On Behalf Of Raul Miller
Sent: Sunday, May 26, 2013 10:49 AM
To: Programming forum
Subject: Re: [Jprogramming] Fwd: Do Out of memory errors vary by J
implementation?
The
Windows Vista 32 bit:
f=: 13 :'(y#1)*/i.y'
]A=:f 12
0 1 2 3 4 5 6 7 8 9 10 11
0 1 2 3 4 5 6 7 8 9 10 11
0 1 2 3 4 5 6 7 8 9 10 11
0 1 2 3 4 5 6 7 8 9 10 11
0 1 2 3 4 5 6 7 8 9 10 11
0 1 2 3 4 5 6 7 8 9 10 11
0 1 2 3 4 5 6 7 8 9 10 11
0 1 2 3 4 5 6 7 8 9 10 11
0 1 2 3 4 5 6 7 8 9 10 11
0 1 2
Can you post your commands? It would be an interesting exercise trying
to optimize for performance.
-Dan
I will be happy to share my commands, with the disclaimer that I'm a novice
at J. My approach is simply what I've been able to cobble together in
isolation.
Suppose you have the
I have worked through the solution arrived at by a few of you to better
learn J, namely this one:
+/,(57=x+/y+/z)*x/y*y/z
In order to fully understand the way the matrix operations are carried out,
I minimized the answer space by making P = 13, and worked through the
output (not shown for
[this is my second attempt at sending - my first attempt at sending
seemed to succeed, but gmail later declared that this was still a
draft.]
On Sun, May 26, 2013 at 8:48 AM, Olivier N.
onemailid4mailingli...@edpnet.be wrote:
In Elton Wang's implementation, I can see one trivial change that
Sorry about the small font in the last post, corrected here:
I need to work on the last bit with the [/] in it, and the use of ~ here.
It is sometimes hard for a beginner to realize where one word begins and
another ends, or if they are combinations (dyads). It took me a while to
get the * as a
Raul wrote: I think that any time we delve into some area of computation that
leaving and coming back after an extended absence can leave us in a jarring
situation where we need to reacquaint ourselves with the original topic. I do
not know of any general cure for this, finding good names for
My reference to Perl's output was of the solutions printed on the count
lines such as this:
1: 2 27 28
2: 3 26 28
3: 4 25 28
.
60: 17 19 21
61: 18 19 20
Total 61
Raul, thank you so much for your other pointers on inspecting the arrays. I
will have two more days after work going over all of
Couldn't sleep. Turns out it soesn't take too long to brute force it by
pencil and paper.
Given z is 28..1, y is 27..1 and x is 26..1, you start with z at 28 and y
at 27 and x at 2. It took me 15 minutes to enumerate the list of 61
solutions. Certainly not near J's speed, but I would have thought
I'm really out of practice with J, and the meager-to-nonexistent documentation
is not helping me. I have a very simple task to perform. I have a text file
infile.txt on my desktop and here's what I want to do:
(1) read the file as lines (so I don't get all the end-of-line symbols);
(2) sort
Is this a start to your indexing request? $. produces a sparse array.
$. ((57=[+/+/)*[/]*/)~ i. 29
2 27 28 | 1
3 26 28 | 1
4 25 28 | 1
4 26 27 | 1
5 24 28 | 1
[...]
17 18 22 | 1
17 19 21 | 1
18 19 20 | 1
On Sun, May 26, 2013 at 2:54 PM, Robert Herman rpjher...@gmail.com wrote:
My
It looks as though your version of 'text.ijs' does NOT include cuttext.
On Sun, May 26, 2013 at 3:50 PM, Murray Eisenberg mur...@math.umass.eduwrote:
I'm really out of practice with J, and the meager-to-nonexistent
documentation is not helping me. I have a very simple task to perform. I
have
sortandprint=:4 : 0
text=.'b' fread y
text=./:~text
text=.text,.LF
(;text) fwrite x
)
The 'b' option means box each line.
y is file to read,
x is file to write sorted.
If you are dealing with windows and need CRLF as a line separator, replace
the LF with CRLF.
On Sun, May 26, 2013 at
to index the solution:
ind=. (57=x+/y+/z)*x/y*y/z
triples =. _3 ]\ x,0 1/y,0 0/z
ans =. (,ind) # triples
From: Robert Herman rpjher...@gmail.com
To: programm...@jsoftware.com
Sent: Sunday, May 26, 2013 2:01 PM
Subject: Re: [Jprogramming] Nested looping for a
There was a missing , in triples in my previous message.
But Brian's answer is the most direct one. $.
triples =. _3 ]\ ,x,0 1/y,0 0/z
From: elton wang ahala2...@yahoo.com
To: programm...@jsoftware.com programm...@jsoftware.com
Sent: Sunday, May 26, 2013
how about (phase-/phase)%lineReactance
note that the diagonal elements of phase-/phase will be 0 but also note
that with line reactances of 0 the 0/0 terms will be 0
however- the problems may well be with the non zero phase differences
and 0 reactances. so you need to eliminate the
One issue is that J's ~ convention is not the OS convention, so you
will need to deal with that. If you are not on windows (which is
probably the case if you are using a ~ OS convention), you can use
HOME=: 2!:5'HOME'
INFILE=: HOME,'/Desktop/infile.txt'
OUTFILE=: HOME,'/DESKTOP/outfile.txt'
On Sun, May 26, 2013 at 2:54 PM, Robert Herman rpjher...@gmail.com wrote:
My reference to Perl's output was of the solutions printed on the count
lines such as this:
1: 2 27 28
2: 3 26 28
3: 4 25 28
.
60: 17 19 21
61: 18 19 20
Total 61
I see that you have already been given an
Let's say a real number ought to be zero if its absolute value is : the
comparison tolerance 2^_44 . Write a verb clean that replaces real numbers
that ought to be zero with zero. How would you clean a complex number?
1 o. 1r2p1 * i. 5
0 1 1.22465e_16 _1 _2.44929e_16
clean 1 o. 1r2p1
clean=: (* |@*).+.
Eugene McDonnell objected when we made *x to be 0 for x near 0, saying that
*x should be 0 only if x is 0.
On Sun, May 26, 2013 at 9:32 PM, km k...@math.uh.edu wrote:
Let's say a real number ought to be zero if its absolute value is : the
comparison tolerance 2^_44 .
I didn't think of Signum! Thanks, Roger.
Sent from my iPad
On May 26, 2013, at 11:56 PM, Roger Hui rogerhui.can...@gmail.com wrote:
clean=: (* |@*).+.
Eugene McDonnell objected when we made *x to be 0 for x near 0, saying that
*x should be 0 only if x is 0.
On Sun, May 26, 2013 at
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