Re: [sympy] Image based on interval

2013-10-30 Thread Alexander Birukov
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

Re: [sympy] Image based on interval

2013-10-30 Thread Matthew Rocklin
The imageset function is our interface for this in the development version >>> domain = Interval(0, sqrt(3)) >>> result = imageset(x, x**3 - 3*x, domain) It doesn't guarantee to give you back a nice set though. It defaults to an ImageSet object which can answer some questions like set membership

Re: [sympy] Image based on interval

2013-10-30 Thread Christophe Bal
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 > Hello everyone. > > Was wondering how can I get an image of function if I have an interval for > it (problem comes if I have

[sympy] Image based on interval

2013-10-30 Thread Alexander Birukov
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 sour

[sympy] Re: Fourier Transform of constants and positive powers of x.

2013-10-30 Thread Pablo Puente
Yes, this is a defect. I created in fact a Issue this week for it: https://code.google.com/p/sympy/issues/detail?id=4079 On Wednesday, October 30, 2013 12:03:32 PM UTC+1, Harsh Gupta wrote: > > >>> from sympy.integrals import transforms > >>> FT = fourier_transform > >>> from sympy.abc import x,

Re: [sympy] Re: alternate representation for Piecewise definition

2013-10-30 Thread Aaron Meurer
On Oct 30, 2013, at 5:39 AM, Chris Smith wrote: Yes, we would have to switch to conditions first. But the issues of evaluation order would require an OrderedDict as you say. I don't recall if we have that yet. OrderedDict is in Python 2.7+. There's a recipe that can be added for 2.6. I don't b

Re: [sympy] Re: alternate representation for Piecewise definition

2013-10-30 Thread Chris Smith
desmos, btw, also evaluates items in the order given from left to right. -- You received this message because you are subscribed to the Google Groups "sympy" group. To unsubscribe from this group and stop receiving emails from it, send an email to sympy+unsubscr...@googlegroups.com. To post to

Re: [sympy] Re: alternate representation for Piecewise definition

2013-10-30 Thread Chris Smith
Yes, we would have to switch to conditions first. But the issues of evaluation order would require an OrderedDict as you say. I don't recall if we have that yet. -- You received this message because you are subscribed to the Google Groups "sympy" group. To unsubscribe from this group and stop

[sympy] Fourier Transform of constants and positive powers of x.

2013-10-30 Thread Harsh Gupta
>>> from sympy.integrals import transforms >>> FT = fourier_transform >>> from sympy.abc import x, k >>> FT(1,x,k) 0 Sympy evaluates the fourier transform of 1 as 0 though it is dirac_delta(k). Similarly sympy evaluates the fourier transform of powers of x as 0 as well. http://mathworld.wolfram.c