Task is: find image/preimage, if you have n f-s, its interval(-s) (if
empty, then (-oo, +oo)) and user interval input.
Example:
2
x**4 - 16x - function
[14, 55) - func interval
2*x - 4
[0, 44]
1
[54, +oo) - user interval
I'm parsing input with regexp transforming input to sympy-understandable
data, then I have to Intersect interval user gave and intervals of function
and so on.
Here comes another problem. It was done w/o sympy few days ago, but once
you hit functions like x**3 - 3*x, you're gonnna find y' (and question
right now how I'm supposed to find the higher exponent in eq, but I think
it's possible), and then solve it. Finding y' isnt that hard, it's another
parsing work, but it req. lots of presets: replace this to that etc. Then I
look a bit future and I see: more problems comes, so I decided to use
SymPy.
So I've done input, I have something like that right now:
1
x*3 - 55
1
[3, 56)
{0: [3*x - 55, (-oo, oo)]} - data stores in dict keyed by non-negative
integers, it already finds intersection and replacing it to new interval.
четверг, 31 октября 2013 г., 2:27:08 UTC+4 пользователь Christophe Bal
написал:
>
> Hello,
> I think that this problem is impossible to solve in general.
>
> What are the functions you want to study ?
>
> Christophe, a simple user
>
>
> 2013/10/30 Alexander Birukov <[email protected] <javascript:>>
>
>> Hello everyone.
>>
>> Was wondering how can I get an image of function if I have an interval
>> for it (problem comes if I have unioned intervals. I dont know how can I
>> call each interval start/end or at least split union into Nth intervals).
>> SymPy docs gives info about transform. but I've browsed source code and
>> it's not even loaded as well as out of source files. So, it's taken away?
>>
>> Example of what I want (basically, it can be any function, keyboard
>> input):
>>
>> f : R -> R
>> f(x) = x**3 - 3*x, x in R
>>
>> f([0, sqrt(3)] = [-2, 0]
>>
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>
>
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