some updates on this, Original definitions:
to2 =: [: <"1 [: ,."0/&>/ [ +&.> [: i.@:>:&.> -~
to =: 2 : 'm ,@:to2 n'
and=: ~.@:,&boxopen
less =: -.&boxopen
a conjunction that takes n (or v"_) as the selection indexes, and then uses x
if any as the updateto indexes, and assigns to those indexe
Another workaround would be convert integers to floating point numbers on
the J side.
_j.Do("a =: (0.5-0.5)+ 10 20 30");
Another issue with J COM was it can not handle wide unicode characters as
reported by Alex Rufon.
On Aug 19, 2014 7:37 PM, "Eric Iverson" wrote:
> The bugs in J64 com are unl
This might be a good use of dissect, to see the shapes and values all at
once.
http://www.jsoftware.com/jwiki/Vocabulary/Dissect
Henry Rich
On 8/20/2014 7:27 PM, Mike Day wrote:
Raul's right of course.
Although Wx is indeed a scalar, Nc and so NcI are 1x1 matrices.
NcI acts like a scalar,
Raul's right of course.
Although Wx is indeed a scalar, Nc and so NcI are 1x1 matrices.
NcI acts like a scalar, but if we replace NcI by scalar nci (say), then
CT mp NcI mp C
may be replaced by CT mp nci * C , or CT mp C * nci , etc.
Mike
On 20/08/2014 15:42, Mike Day wrote:
0. Your J e
On Wed, Aug 20, 2014 at 10:42 AM, Mike Day wrote:
> 1. Nc = C.Nb.CT is scalar, and therefore NcI is also scalar.
...
> Please note that scalar part-expressions could be moved around, and they may
> be applied with a simple * verb.
> I haven't done that here.
Note that expressing these values as
0. Your J expression for Wx looks wrong to me.
If you want to get
Wx = (1-(q0^2)-(q1^2)-(q2^2)-(q3^2))%2 in conventional arithmetic notation
then you need
Wx=:(1-(q0^2)+(q1^2)+(q2^2)+(q3^2))%2
or
Wx=:(1-+/*:q)%2 NB. Your J-expression is effectively (1- -/ *:q)%2
or
[Wx=: -: -. +/
Thanks for quick answer
Erik
- Eredeti levél (Original Message) -
Feladó: Raul Miller
Dátum: Szerda, Augusztus 20, 2014 11:27 de
Tárgy: Re: [Jprogramming] Matrix equation
Címzett: Programming forum
> I think what you are asking about is: where do you put the
> parenthesis?
> That sugg
Thank you for your answer. Yes I try to write a J program for 3D similarity
transformation.
Erik Papp
- Eredeti levél (Original Message) -
Feladó: Henry Rich
Dátum: Szerda, Augusztus 20, 2014 1:39 du
Tárgy: Re: [Jprogramming] Matrix equation
Címzett: programm...@jsoftware.com
> I have
I have no idea what this equation is trying to do, but the pattern
NbI * (...) * NbI
looks like it's trying to be a similarity transformation, but one of the
outer matrices would need to be the inverse of the other.
Just wondering,
Henry Rich
On 8/20/2014 5:24 AM, Raul Miller wrote:
I thin
IIRC matrix multiplication is non-associative, without parenthesis, J is
post multiplication.
Or I was wrong.
On Aug 20, 2014 5:26 PM, "Raul Miller" wrote:
> I think what you are asking about is: where do you put the parenthesis?
>
> That suggests:
>
> dX=: ((NbI-NbI mp CT mp NcI mp C mp NbI)m
I think what you are asking about is: where do you put the parenthesis?
That suggests:
dX=: ((NbI-NbI mp CT mp NcI mp C mp NbI)mp W)+NbI mp CT mp NcI mp Wx
In other words, you almost had it.
Thanks,
--
Raul
On Wed, Aug 20, 2014 at 3:43 AM, "Papp Erik Tamás"
wrote:
> Dear Forum,
>
> Can s
Dear Forum,
Can somebody help me to solve the folloving matrix equation?
pps=:9!:11 NB. set print precision
pps 20
mp=: +/ . * NB. Matrix product
NB.===
NB. The following matrix e
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