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.Tue, 01 Feb 2011 12:24:55 +0100When does 1/2=0 ? (python's integer division Vs Sage's exact fractions)https://ask.sagemath.org/question/7917/when-does-120-pythons-integer-division-vs-sages-exact-fractions/Hi all !
I know that python evaluates 1/2 to zero because it is making an integer division. Well. I was expecting Sage not to do so.
It does more or less ...
------ sagess.py ----------
#! /usr/bin/sage -python
# -*- coding: utf8 -*-
from sage.all import *
def MyFunction(x,y):
print x/y
MyFunction(1,2)
------ end of sagess.py ----------
When I launche that script from the command line, I got what Python would give :
18:08:03 ~/script >$ ./sagess.py
0
But when I launch it from the sage'terminal it is less clear how it works :
18:16:04 ~/script >$ sage
----------------------------------------------------------------------
| Sage Version 4.5.3, Release Date: 2010-09-04 |
| Type notebook() for the GUI, and license() for information. |
----------------------------------------------------------------------
sage: import sagess
0
sage: sagess.MyFunction(1,2)
1/2
At the import, it returns zero, but when I reask the same computation, it gives the correct 1/2
I know that writing
float(x)/y
"fixes" the problem. But it looks weird and I want to keep exact values.
What do I have to write in my scripts in order to make understand to Sage that I always want 1/2 to be 1/2 ?
Thanks
Have a good night !
Laurent
Laurent ClaessensTue, 01 Feb 2011 12:24:55 +0100https://ask.sagemath.org/question/7917/