ASKSAGE: Sage Q&A Forum - Latest question feedhttps://ask.sagemath.org/questions/Q&A Forum for SageenCopyright Sage, 2010. Some rights reserved under creative commons license.Fri, 08 May 2015 19:07:36 -0500qepcad failing to replicate exampleshttps://ask.sagemath.org/question/26770/qepcad-failing-to-replicate-examples/ I was attempting to replicate the examples seen here (http://www.sagemath.org/doc/reference/interfaces/sage/interfaces/qepcad.html), but I keep getting errors.
Given
︠482004e5-daf3-4312-b5d7-a61b41d210a4s︠
var('a,b,c,d,x,y,z')
qf = qepcad_formula;
ellipse = 3*x^2 + 2*x*y + y^2 - x + y - 7
F = qf.exists(y, ellipse == 0); F
qepcad(F)
︡202e02ca-ac90-4b34-afab-7d6ceb6d41f5︡{"stdout":"(a, b, c, d, x, y, z)\n"}︡{"stdout":"(E y)[3 x^2 + 2 x y + y^2 - x + y - 7 = 0]\n"}︡{"stderr":"Error in lines 5-5\n"}︡{"stderr":"Traceback (most recent call last):\n File \"/projects/45572f4b-6bd1-49bd-9d46-5f340788b465/.sagemathcloud/sage_server.py\", line 879, in execute\n exec compile(block+'\\n', '', 'single') in namespace, locals\n File \"\", line 1, in <module>\n File \"/usr/local/sage/sage-6.5/local/lib/python2.7/site-packages/sage/interfaces/qepcad.py\", line 1431, in qepcad\n qe = Qepcad(formula, vars=vars, **kwargs)\n File \"/usr/local/sage/sage-6.5/local/lib/python2.7/site-packages/sage/interfaces/qepcad.py\", line 777, in __init__\n qex._send('[ input from Sage ]')\n File \"/usr/local/sage/sage-6.5/local/lib/python2.7/site-packages/sage/interfaces/expect.py\", line 212, in _send\n self._start()\n File \"/usr/local/sage/sage-6.5/local/lib/python2.7/site-packages/sage/interfaces/expect.py\", line 445, in _start\n raise RuntimeError(\"unable to start %s\" % self.name())\nRuntimeError: unable to start QEPCAD\n"}︡
︠5c912bc8-cd8b-495c-9fa3-eda33c34530e︠
MickleMouseFri, 08 May 2015 19:07:36 -0500https://ask.sagemath.org/question/26770/code for finding tail and head of an edge in a bipartite graphhttps://ask.sagemath.org/question/10049/code-for-finding-tail-and-head-of-an-edge-in-a-bipartite-graph/How to write code to find the tail and head of an edge in a bipartite graph?REKHA BISWALMon, 22 Apr 2013 01:03:47 -0500https://ask.sagemath.org/question/10049/Converting string into number does not work properlyhttps://ask.sagemath.org/question/9033/converting-string-into-number-does-not-work-properly/Sage can convert huge integer number into string very quickly but the opposite way it is very slow:
n=2^7000000;
s=str(n); (very fast)
m=int(s); (very slow)
I also used "eval" and "sage_eval" instead of "int" with same result, i.e. converting from huge string into integer number is very slow.
It should take about same time in both cases since variables n, m and s are of the same length.
Do you have any idea why is this so?
Mathematica is much more faster in evaluating the above operations.azerbajdzanWed, 06 Jun 2012 00:51:08 -0500https://ask.sagemath.org/question/9033/How to install a new module for Sage?https://ask.sagemath.org/question/8843/how-to-install-a-new-module-for-sage/Edit: this is a duplicate of [this question](http://ask.sagemath.org/question/1283/how-to-use-sage-in-terminal).
Dear All,
I am trying to use sage in Mac OSX. I already installed the binary distribution.
The problem is I cannot access the sage environment in terminal and when I
run sage in Mac it opens Sage Notebook. The thing is I am trying to install
PyMVPA and Nibabel in Sage, but as I look into guides I need to go through these
steps according to:
http://sites.google.com/site/neuroinformaticsimageanalysis/home/sage-in-medical-imaging
Install pynifti and pymvpa
-Download latest versions of pynifti and pymvpa
-In the unpacked directories of pynifti and pymvpa and within a Sage environment
(i.e. " $ sage -sh "), install the modules. I.e. " $ make all " and " $ python setup install ".
Check installation by " sage: import pynifti " and " sage: import mvpa "
and when I type "sage -sh" in terminal it opens the sage process and the notebook in Safari!
So I don't know where and when I need to type the rest which are "make all" and "python setup install"
I would be really grateful if someone helps.NajiSun, 01 Apr 2012 10:35:13 -0500https://ask.sagemath.org/question/8843/Quantum binomialshttps://ask.sagemath.org/question/7596/quantum-binomials/What is the difference between `q.analogues.q_binomial(n,k)` and `gaussian_binomial(n,k)`?
Superficially they seem to be the same.BWWThu, 19 Aug 2010 10:14:06 -0500https://ask.sagemath.org/question/7596/