Hello Brian and others,
After finding the first root x1 you can deflate the original equation by
dividing it by (x-x1) .
Esa
load'math/calculus'
Newton =: adverb : ']-u%(u deriv_jcalculus_ 1)'(^:_)("0)
(+:-^~) Newton 0.5
0.346323
((+:-^~)%-&0.346323) Newton 1
2
-Original Message--
]x=.i:3
_3 _2 _1 0 1 2 3
0^x
_ _ _ 1 0 0 0
x=.0
(x^x)=2*x
0 NB. Zero is not a root
(x^x)=2*x
0
x^x
1
2*x
0
So why does Newton Raphson show a zero root for (x^x)=2*x?
(^~ - +:) Newton 2
2
(^~ - +:) Newton 1
0 NB. Something wrong here!
(x^x)=2*x ?
Skip Cave
Cave Consulting LLC
Android with armv7 cpu are 32 bit, with armv8 cpu are 64 bit. They give
different results for RNG.
32 vs 64 bit can be checked by the global noun IF64
On Thu, Feb 6, 2020, 9:18 PM 'Rob Hodgkinson' via Programming <
programm...@jsoftware.com> wrote:
> Hi Arnab, further to Pascal’s note I would
Bo is correct
There is a "zero rule" so n^0 =1 if n is not equal to 0. Bo is correct
the only possible 0^0 is the same as 0*0
Possibly the coding for ^ should take this into account.
On 2020-02-05 10:14 p.m., Skip Cave wrote:
Bo,
The original equation is:
(x^x)=2*x
2 is clearly a root. 0 i
+/ . * is so much faster than (+/@:(*"1 _)) that even if you were given
a notation for selecting an axis, the implementation would do the
transpose so that it could use the faster product.
+/@:*"1 is pretty fast for small arguments but for big ones its cache
characteristics mean you end up li
February 6, 2020 11:00 PM, "Henry Rich" wrote:
> It's not so simple to describe. In fact, you haven't described it.
> Your example seems to have a rank-4 array times a rank-5 array producing
> a rank-7 array. Is this result the sum of rank-7 arrays created by
> multiplying rank-3 times rank
Here is a way to permute the axes of an array that you might find easier
to work with:
A =. i. 2 3 4 5
$ ('ijkl'i.'ljik') |: A
5 3 2 4
The idea is that we start with A, which has axes ijkl, and want to
shuffle them around to get ljik. So we look up each of the letters ljik
in ijkl, which gi
It's simple mathematically, because you've already learned that and
because you are willing to elide discussion of various mechanical
details.
Personally, I had to read your question a couple of times, and then
Henry's response and then your question again to resolve some of the
ambiguities.
The
It's not so simple to describe. In fact, you haven't described it.
Your example seems to have a rank-4 array times a rank-5 array producing
a rank-7 array. Is this result the sum of rank-7 arrays created by
multiplying rank-3 times rank-4? I don't know how to make that jibe
with 'the usual
Henry Rich writes:
> It depends on what the '*' means in the definition of the product.
>> C_ijlmnop = sum_k A_ijkl * B_mknop
I really mean the usual multiplication (of numbers).
> Have a look at
>
> a =. i. 2 3 4 5
> b =. i. 2 4 3 5 6
> $ (2 |: a) +/ . * ((|:~ 1 -.~ i.@(#@$)) b)
> 2 3 5 2 3
It depends on what the '*' means in the definition of the product. Have
a look at
a =. i. 2 3 4 5
b =. i. 2 4 3 5 6
$ (2 |: a) +/ . * ((|:~ 1 -.~ i.@(#@$)) b)
2 3 5 2 3 5 6
Henry Rich
On 2/6/2020 2:46 PM, rsyk...@disroot.org wrote:
Dear list,
having two multidimensional matrices
Dear list,
having two multidimensional matrices A and B,
with some indices, say, A_ijkl and B_mknop,
how can I obtain a matrix C, where
C_ijlmnop = sum_k A_ijkl * B_mknop
ie., C has all indices of A and B but for the index k,
which was summed over.
Thanks for your suggestions.
Best regards
Rud
solve: (x^x)=2*x
JVERSION
Engine: j901/j64avx2/windows
Release-e: commercial/2020-01-29T11:17:19
Library: 9.01.18
Qt IDE: 1.8.5/5.12.6
Platform: Win 64
Installer: J901 install
InstallPath: c:/users/skip/j901
Contact: www.jsoftware.com
load 'math/calculus'
Newton =: adverb : ']-u%(u der
I do not think that I said that 5!:5 produces erroneous results.
I think I said that when non-nouns are involved that the result of
5!:5 may not be a suitable ". argument.
Here's an example:
example=:3 :0
a=:'this'
b=:a,' is a'
b,y
)
With that definition, this works:
example i.0
B
2.
? (1 | <. 1000 * 6!:1 '') # 0
Henry Rich
On 2/6/2020 7:21 AM, Arnab Chakraborty wrote:
Dear all,
For my class of about 30 students armed with JAndroid 901, I had planned to
use ?. to generate a random matrix which should be same for everybody. To
start with, I asked everybody to try
1. Choose a different starting guess
2. Update the addon
Henry Rich
On 2/6/2020 10:36 AM, Brian Schott wrote:
Henry et al,
I have 2 questions.
How would the second root at 2 be found with Skip's problem?
Why do I get the following error?
server:~ brian$ /Users/brian/j901/bin/jconsole ; exit
Yes, I can see that would track with minimal risk. Thank you.
On 02/05/2020 10:38 PM, Devon McCormick wrote:
The Boolean indicator vector sounds like a good way to handle this.
On Wed, Feb 5, 2020 at 2:33 PM Don Guinn wrote:
Yes. I just wanted to make sure he was aware that that would happe
Henry et al,
I have 2 questions.
How would the second root at 2 be found with Skip's problem?
Why do I get the following error?
server:~ brian$ /Users/brian/j901/bin/jconsole ; exit;
JVERSION
Engine: j901/j64avx/darwin
Release-c: commercial/2020-01-11T12:22:31
Library: 9.01.20
Platform: Darwi
?. should be stable but different result on J32 vs J64
J32
'89551d61c612f81fb7553a355bf932d2d8f78ed7' -: (128!:6) ": ?.#~1e6
J64
'6ebe83e54f37c4cdb3cfb617e657af9dd2074c42' -: (128!:6) ": ?.#~1e6
Thu, 06 Feb 2020, bill lam написал(а):
> Strange, I got 94 on arm64.
>
> Did 32bits and 64bits get
Strange, I got 94 on arm64.
Did 32bits and 64bits get different results?
On Thu, Feb 6, 2020, 8:21 PM Arnab Chakraborty wrote:
> Dear all,
>
> For my class of about 30 students armed with JAndroid 901, I had planned to
> use ?. to generate a random matrix which should be same for everybody. To
Hi Arnab, further to Pascal’s note I would suggest the following approach:
Set the random seed for the RNG to a value you desire (see the Foreign
Conjunction 9!:1 )
Then call ?n as you wish to produce a sequence as many times as you wish
Repeat sequence above to reproduce from a p
The initial seed is the same each time you start J.
?. differs on 32 and 64 bit systems, with default generator.
On Thursday, February 6, 2020, 07:21:31 a.m. EST, Arnab Chakraborty
wrote:
Dear all,
For my class of about 30 students armed with JAndroid 901, I had planned to
use ?. to ge
Dear all,
For my class of about 30 students armed with JAndroid 901, I had planned to
use ?. to generate a random matrix which should be same for everybody. To
start with, I asked everybody to try
?. 100
Some got 46, others got 93. No other values. Next, someone noticed that if
they repeatedly t
The new version works perfectly with Android 5. Thanks a lot, Bill!
On Tue, Feb 4, 2020 at 7:41 PM 'Sergey Kamenev' via Programming <
programm...@jsoftware.com> wrote:
> Now working!
>
> Thank you
>
> 04.02.2020 11:49, bill lam пишет:
> > I can reproduce the crash on Android 5. It was some
> > il
Write down the equation on paper and then use android
mathway app to take a photo of it, and it solved
x=0.34632336,2
--
regards,
GPG key 1024D/4434BAB3 2008-08-24
gpg --keyserver subkeys.pgp.net --armor --export 4434BAB3
--
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