ASKSAGE: Sage Q&A Forum - RSS feedhttps://ask.sagemath.org/questions/Q&A Forum for SageenCopyright Sage, 2010. Some rights reserved under creative commons license.Fri, 26 Feb 2016 07:29:45 +0100Implementing new CF class advicehttps://ask.sagemath.org/question/32672/implementing-new-cf-class-advice/My goal is to implement Gosper's algorithm for algebraic operations on continued fractions into Sage. To begin with, I would like to implement a functionality to perform a homographic transformation
$$x \rightarrow \frac{ax + b}{cx + d}$$
where $x$ is a CF.
The easiest way to do this is probably to create a new class in `sage.rings.continued_fraction` that would on inicialization accept the integer constants $a, b, c, d$ and a descendant of `ContinuedFraction_base` class. The most important method of this class would be `next()` or `_iter_()`, which would read the input $x$ until it can output new term using Gosper's algorithm.
How do I create an instance of this class with proper arguments, when for example $(3*x + 1)/2$, where $x$ is a CF, is called from Sage? (Instead of `_mul_()` being called, than `_add_()` and so on...)
Simplifying using inbuilt Sage methods and then evaluating the expression as a string using regular expressions somehow (like [this](http://sunjay.ca/2014/04/27/evaluating-simple-math-expressions-using-python-and-regular-expressions/)) might be a solution, but I am not sure if the best one.
Thank you very much for any advice on this!
EDIT: I have found this promising [link](http://doc.sagemath.org/html/en/thematic_tutorials/coercion_and_categories.html), but haven't found anything useful in there so far...mirgeeFri, 26 Feb 2016 07:29:45 +0100https://ask.sagemath.org/question/32672/