On Thu, May 15, 2008 at 4:04 PM, Robert Bradshaw
<[EMAIL PROTECTED]> wrote:
>
> On May 15, 2008, at 8:21 AM, Bjake Hammersholt Roune wrote:
>
>>> [...] people are confused that when
>>> they create a matrix with matrix(3, range(9)), for example, that the
>>> echelon_form is not the rref output tha
On May 15, 2008, at 8:21 AM, Bjake Hammersholt Roune wrote:
>> [...] people are confused that when
>> they create a matrix with matrix(3, range(9)), for example, that the
>> echelon_form is not the rref output that they get from most any other
>> program they have ever used [...]
>> What do peopl
> >> What do people think about making the default ring for matrices QQ?
>
> > I have no objections to making QQ the defailt ring for matrices.
>
> I do. That's definitely *not* the proposal. The proposal is to make the
> base ring the fraction field of the canonical ring in which the list of
>
Nils Bruin wrote:
> -1. While I agree that defaulting to matrices over QQ rather than over
> ZZ would lead to more expected behaviour for most users, I don't see
> how the rule for changing the base ring can be made both consistent
> and cheap.
>
> Imagine R1 = QQ[x,y]/(x^2+y^2-1). Then FieldOfFr
I agree with Nick here. If we want to change the default behavior of
some functions so that they work the same as over the fraction field,
that's fine. But don't add a call to fraction field to the
constructor. ZZ is the initial object in the category of rings.
That's a good reason for it to be
-1. While I agree that defaulting to matrices over QQ rather than over
ZZ would lead to more expected behaviour for most users, I don't see
how the rule for changing the base ring can be made both consistent
and cheap.
Imagine R1 = QQ[x,y]/(x^2+y^2-1). Then FieldOfFractions(R1) is well-
defined,
> I'm not sure I understand the problem. Here is an example session in
> Sage 3.0.1. Can you change this to illustrate what you mean?
>
Sorry, Jason, the example was sort of buried in my post. Here is a
concise version.
sage: A=matrix(QQ,3,range(9))
sage: A
[0 1 2]
[3 4 5]
[6 7 8]
sage: A.r
William Stein wrote:
> On Thu, May 15, 2008 at 8:21 AM, Bjake Hammersholt Roune
> <[EMAIL PROTECTED]> wrote:
>>> [...] people are confused that when
>>> they create a matrix with matrix(3, range(9)), for example, that the
>>> echelon_form is not the rref output that they get from most any other
>>
Bjake Hammersholt Roune wrote:
>> [...] people are confused that when
>> they create a matrix with matrix(3, range(9)), for example, that the
>> echelon_form is not the rref output that they get from most any other
>> program they have ever used [...]
>> What do people think about making the defau
On Thu, May 15, 2008 at 9:04 AM, Nick Alexander <[EMAIL PROTECTED]> wrote:
>
>> What do people think about making the default ring for matrices QQ?
>
> I'm not certain why I dislike this so much, but I vote -1. I think
> it's because I understand the Sage coercion model well and since I
> know wh
> What do people think about making the default ring for matrices QQ?
I'm not certain why I dislike this so much, but I vote -1. I think
it's because I understand the Sage coercion model well and since I
know what to expect, I appreciate my data starting at the "lowest
level of the model".
kcrisman wrote:
>
>
> On May 15, 10:55 am, "William Stein" <[EMAIL PROTECTED]> wrote:
>> On Thu, May 15, 2008 at 7:48 AM, Jason Grout
>>
>>
>>
>> <[EMAIL PROTECTED]> wrote:
>>
>>> Jason Grout wrote:
Based on some conversations with linear algebra people and classroom
demonstrations in
On Thu, May 15, 2008 at 8:21 AM, Bjake Hammersholt Roune
<[EMAIL PROTECTED]> wrote:
>
>> [...] people are confused that when
>> they create a matrix with matrix(3, range(9)), for example, that the
>> echelon_form is not the rref output that they get from most any other
>> program they have ever us
On Thu, May 15, 2008 at 8:16 AM, kcrisman <[EMAIL PROTECTED]> wrote:
>
>
>
> On May 15, 10:55 am, "William Stein" <[EMAIL PROTECTED]> wrote:
>> On Thu, May 15, 2008 at 7:48 AM, Jason Grout
>>
>>
>>
>> <[EMAIL PROTECTED]> wrote:
>>
>> > Jason Grout wrote:
>> >> Based on some conversations with line
On Thu, May 15, 2008 at 8:15 AM, didier deshommes <[EMAIL PROTECTED]> wrote:
>
> On Thu, May 15, 2008 at 10:48 AM, Jason Grout
> <[EMAIL PROTECTED]> wrote:
>> More concisely, this proposal could be worded:
>>
>> What do people think of making matrix() return a matrix over a field by
>> default,
didier deshommes wrote:
> On Thu, May 15, 2008 at 10:48 AM, Jason Grout
> <[EMAIL PROTECTED]> wrote:
>> More concisely, this proposal could be worded:
>>
>> What do people think of making matrix() return a matrix over a field by
>> default, unless a ring is explicitly specified. The default fi
> [...] people are confused that when
> they create a matrix with matrix(3, range(9)), for example, that the
> echelon_form is not the rref output that they get from most any other
> program they have ever used [...]
> What do people think about making the default ring for matrices QQ?
>
I have no
On May 15, 10:55 am, "William Stein" <[EMAIL PROTECTED]> wrote:
> On Thu, May 15, 2008 at 7:48 AM, Jason Grout
>
>
>
> <[EMAIL PROTECTED]> wrote:
>
> > Jason Grout wrote:
> >> Based on some conversations with linear algebra people and classroom
> >> demonstrations in a linear algebra class, peop
On Thu, May 15, 2008 at 10:48 AM, Jason Grout
<[EMAIL PROTECTED]> wrote:
> More concisely, this proposal could be worded:
>
> What do people think of making matrix() return a matrix over a field by
> default, unless a ring is explicitly specified. The default field would
> either be the fract
On May 15, 4:20 pm, Jason Grout <[EMAIL PROTECTED]> wrote:
> matrix(3, range(9)) would yield a matrix over QQ
+1
many just use integers as cheap examples but in fact use them over QQ
h
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On Thu, May 15, 2008 at 7:48 AM, Jason Grout
<[EMAIL PROTECTED]> wrote:
>
> Jason Grout wrote:
>> Based on some conversations with linear algebra people and classroom
>> demonstrations in a linear algebra class, people are confused that when
>> they create a matrix with matrix(3, range(9)), for ex
Jason Grout wrote:
> Based on some conversations with linear algebra people and classroom
> demonstrations in a linear algebra class, people are confused that when
> they create a matrix with matrix(3, range(9)), for example, that the
> echelon_form is not the rref output that they get from mos
I think this is a good idea.
-M. Hampton
On May 15, 8:20 am, Jason Grout <[EMAIL PROTECTED]> wrote:
> Based on some conversations with linear algebra people and classroom
> demonstrations in a linear algebra class, people are confused that when
> they create a matrix with matrix(3, range(9)), fo
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