ASKSAGE: Sage Q&A Forum - Latest question feedhttp://ask.sagemath.org/questions/Q&A Forum for SageenCopyright Sage, 2010. Some rights reserved under creative commons license.Wed, 22 Nov 2017 23:38:05 -0600How can I compose 2 power series in one variable with their compositional inverse get a power series in two variables?http://ask.sagemath.org/question/39739/how-can-i-compose-2-power-series-in-one-variable-with-their-compositional-inverse-get-a-power-series-in-two-variables/I would like to compose a power series $\ell$ defined in $x$ to get a power series $\ell^{-1}(\ell(x) + \ell(y))$ as a power series $f(x, y)$ in two variables, $x$ and $y$. In the code below I call l := $\ell$, and e := $\ell^{-1}$.
PREC = 20
R.<x, y> = PowerSeriesRing( QQ, default_prec=PREC )
f = exp( 1/3 * log( 1-x^3 ) )
print f
w = 1/f
l = w.integral(x)
e = l.reverse()
g = e(l(x) + l(y)) ??
I find immediately the following issue, let alone the issue of composing:
e = l.reverse()
AttributeError: 'MPowerSeriesRing_generic_with_category.element_class' object has no attribute 'reverse'
Once I have this two variable power series $f(x, y)$, I would like to output $f(x, (f(x, ..., f(x,x)))$, composed with itself $n$-times for a natural number $n$.masseygirlWed, 22 Nov 2017 23:38:05 -0600http://ask.sagemath.org/question/39739/x.digits() for x decimalhttp://ask.sagemath.org/question/34515/xdigits-for-x-decimal/Let
sage: x=1416
sage: v=x.digits()
sage: v.reverse(); v
gives
[1, 4, 1, 6]
That doesn't work for x decimal, as x=3.1416
I would like to have [3, 1, 4, 1, 6] as result in a simple way.logomathThu, 18 Aug 2016 07:56:52 -0500http://ask.sagemath.org/question/34515/Defining a function and forcing max or min valuehttp://ask.sagemath.org/question/8896/defining-a-function-and-forcing-max-or-min-value/Hi,
Is it possible to define a funtion, say f, and have it be the maximum (or minimum) of another function and a constant?
Example (pseudo-script): if g(x)=log(abs(x)), let f(x)=g(x) if g(x)>0, and f(x)=0 for all g(x)<0
Thanks
N.C.sagembTue, 17 Apr 2012 02:08:11 -0500http://ask.sagemath.org/question/8896/Backing into a problemhttp://ask.sagemath.org/question/8814/backing-into-a-problem/Is it possible to back your way into a problem?
Task:
I want to supply an integer and then produce an equation for that.
694 = 26^2 + 4^2 + 2
I would like to reduce the equation size to the most efficient possible.
Shirley99Thu, 22 Mar 2012 09:36:04 -0500http://ask.sagemath.org/question/8814/