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 following this long process of finding the two functions I was
hoping in J there would be a “clean and tidy” way of doing things.
Probably impossible even for simple functions f.
> On 5 Nov 2020, at 2:24 pm, Raul Miller <[email protected]> wrote:
>
> 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 Piet de Jong <[email protected]> wrote:
>>
>> 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 write a function g such that g x gives y and g^:_1 y gives x.
>> But is there a cleaner way? The g and its inverse may be complicated even
>> if f is relatively simple.
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> ----------------------------------------------------------------------
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