jllb's profile - activity

Substitution of variable in polynomial not working as expected. R.<x> = SR[] a = SR.var('a') P = a*x P.subs(a=1)

Hi, I am using a remote sage notebook public server (such as http://sage.math.canterbury.ac.nz/). I would like to be able to load my own python modules, but I don't know how can I access local files, such as

import sys
sys.path.append('path-to-file-in-my-local-drive')
import module-name

Is there any way to do that?

Thank you, however I find this behavior at least strange. If n is a Sage Integer, I understand range(n) produces a list of Python integers. So in both cases the sum runs over a list of Python integers. However, in one case they are converted into Sage integers and in the other case they aren't. I don't understand why.

Consider the following code:

def s(n):
    return sum(k/n for k in range(n + 1))

L0 = s(2)

for n in range(2, 3):
    L1 = s(n)

The answers are (using sage 7.1):

print L0, L1
(3/2, 1)

In the second case sage is using the usual integer division of python 2.x while in the first one it is using the exact representation of rationals. Is this a known bug?

Thank you very much. When you say enable SSL, you mean something as explained in https://www.digitalocean.com/communit... ?

Is it difficult to allow users to create accounts on our Sagemath server using openid authentication? In fact, we would like to use the gmail implementation of openid since our university email is managed by Google. Any hints, please?

Hi, I'm trying to set typeset mode = True using the iPython notebook in Sage 6.4, but I don't find how to do it. Is it already implemented?

F = sqrt((cos(x) - 1)^2 + sin(x)^2)
F.integrate(x, 0, 2*pi)

yields 0, the expected answer is 8.

Version is 6.3. Seems to me sagenb is using an old version without the bug.

var('x y')
solve(x + y, [x, y], solution_dict=True)

yields AttributeError: 'list' object has no attribute 'left'

Is this a bug?

var('x y')
solve(x*y, [x, y])

returns only the solution x=0, missing y=0. Is this a known bug? I am using sage 5.13.

Hi, I would like to manipulate the raw data of a plot. More specifically, I'd like to get the set of points produced by implicit_plot in order to use it for another task. Is that possible?

Here, using Ubuntu 12.04, it consistently yields abs(sin(x))^2. Please note that the similar input abs(sin(x)^2).simplify_full() produces the right answer. Version 5.5 does not have this problem.

I think (abs(sin(x))^2).simplify_full() should render sin(x)^2. This is not the case in sage 5.6 even with the assumption assume(x, 'real'). Is this a [known] bug?

Maple can solve a system of equations such as $\sin x + y =0, \sin x - y =0$. However,

var('x y') solve([sin(x) + y ==0, sin(x) - y==0], [x, y]) produces no useful answer.

Is there any other way to proceed?