Thanks for the reminder. I vaguely remember trying to load it on my fairly
basic android phone, but either having too little memory (electronic) or too
little computing power (brain).
Cheers,
Mike
Sent from my iPad
> On 6 Nov 2020, at 05:59, arie groeneveld wrote:
>
> Hi Mike,
>
> FYI ht
Hi Mike,
FYI https://pari.math.u-bordeaux.fr/paridroid/
cheers
@@i
Op 05-11-2020 om 19:31 schreef 'Michael Day' via Programming:
FWIW,
I've played around with your (Piet's) example in J and Pari-GP, which
is free. Pari-GP doesn't
itself run on Android or iOS phones & tablets, but can be run
Solve[(x^2+Log[y])^(1)==c,y]
> >>
> >> Mathematica can express the output in many forms
> >>
> >> FortranForm[expression]
> >> CForm[expression]
> >> TeXForm
> >>
> >> alas, no JForm
> >>
> >>
> >>>
FWIW,
I've played around with your (Piet's) example in J and Pari-GP, which is
free. Pari-GP doesn't
itself run on Android or iOS phones & tablets, but can be run via SAGE
as far as I understand my iPad!
The J is pretty messy and hardly general! But normal stuff...
NB. General expression f
My approach that suits J ways of solving a much wider class than just this type
of problem. Relies on 2 pretty simple independent concepts.
1. I define a "perfect function" as simply a function that returns all of its
arguments. This is suitable to processing by many J techniques such as ^: t
orm
>>
>> alas, no JForm
>>
>>
>>> Date: Thu, 5 Nov 2020 11:27:36 +1100
>>> From: Piet de Jong
>>> To: Programming forum
>>> Subject: [Jprogramming] Implicit functions
>>> Message-ID: <1db0ce29-6b80-43a2-b82f-309
ject: [Jprogramming] Implicit functions
Message-ID: <[email protected]>
Content-Type: text/plain; charset=utf-8
--
For information about J forums see http://www.jsoftware.com/forums.htm
--
This
express the output in many forms
FortranForm[expression]
CForm[expression]
TeXForm
alas, no JForm
>Date: Thu, 5 Nov 2020 11:27:36 +1100
>From: Piet de Jong
>To: Programming forum
>Subject: [Jprogramming] Implicit functions
>Message-ID: <1db0ce29-6b80-43a2-b82f-309c22dae...@g
In general, global root finding is a hard problem to solve. One can get a
general feel for solutions with a contour plot. I recall this is possible
with plot though I don't recall the syntax off hand. On the other hand,
from FVJ4 5.3
load 'graphics/fvj4/raster'
f=:{{% (*:x) + ^.y}}"0
2 f 1
0.25
Well, for example: https://code.jsoftware.com/wiki/Essays/Newton's_Method
If your function is not supported by J's differentiation mechanism,
you would want to use a different approach. But the function you
mention is differentiable and it looks like J can handle it:
9!:3(5)
require 'math/c
This is a very hard problem and there will not be a J primitive for it.
A J script would be welcome.
Henry Rich
On 11/4/2020 10:58 PM, Piet de Jong wrote:
I was hoping for more of a “J” type solution.
For example if f(x,y) = (x^2 + log y)^{-1} = c
Then given c and say x, I can solve for y.
I was hoping for more of a “J” type solution.
For example if f(x,y) = (x^2 + log y)^{-1} = c
Then given c and say x, I can solve for y. (ie write J function)
Or given c and y I can solve for x. (ie write a J function)
(I’m assuming domains etc are ok. — this is just an example.)
So instead of fo
The answer is: sometimes yes, sometimes no.
See https://en.wikipedia.org/wiki/Equation_solving for some of the issues.
If f can be expressed as a polynomial, you might want to consider
using https://www.jsoftware.com/help/dictionary/dpdot.htm
Thanks,
--
Raul
On Wed, Nov 4, 2020 at 7:27 PM Pie
Still trying to learn/improve my J after 25 years.
Here is the issue. I’m probably having a pipe dream.
Suppose you have an implicit function f(x,y)=0 which is relatively “clean” (ie
simple to specify)
Is there a “clean/efficient” way in J to solve for y given x or vice versa.
I know I can
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