The last thing I want is to start up this thread again, but I have not
been paying attention to edu-sig for awhile and when I came back I
found some things I need to address.
Yes, I know, I read that. I'm not questioning that you know this.
You asked what problems from a CS viewpoint there
- Original Message -
From: Dethe Elza [EMAIL PROTECTED]
Arthur to Kirby:
Are you a CS type? If so, speak directly.
If not, why do you feel compelled to speak on their behalf.
Sorry if I'm mis-reading that, but it looks to me like shut up,
which I find offensive, even if
I appreciate your communication here very much.
Thnks,
Art
Good work, both of you.
I look forward to archived v-lists (video lists). I don't know how
they'd work exactly, but the bandwidth would be a lot higher.
People who're already on the same page could get by with edu-sig type
In a message of Sat, 25 Mar 2006 03:02:31 EST, Arthur writes:
It doesn't matter to me any more than whether my tax calculations are
consistently correct were my class the one you described a few posts back
.
I think I should perhaps appreciate that Kirby is the only one talking
straight to me.
-Original Message-
From: Laura Creighton [mailto:[EMAIL PROTECTED]
Sent: Saturday, March 25, 2006 7:16 AM
To: Arthur
Ok, so it does matter. Are you locking your complex number
before modifying it?
Just to generalize the issue, so that I know, realy, what we are talking
about,
I think they are going on about a very fundamental CS issue: mutable
objects are not thread-safe. If threads are not an issue, then this
has all been hot air, but it came up, IIRC, because the discussion
mentioned the mutable vs. immutable issue, and this always leads one
to concurrency nowadays,
-Original Message-
From: [EMAIL PROTECTED]
[mailto:[EMAIL PROTECTED]
On Behalf Of Michael Tobis
Sent: Saturday, March 25, 2006 10:21 AM
To: edu-sig@python.org
Subject: Re: [Edu-sig] Properties use case
Arthur (addressing you directly) does your code use any
threading
In a message of Thu, 23 Mar 2006 10:49:41 CST, Michael Tobis writes:
Then it is the language implementor's headache to make the locking mec
hanism work.
from threading import Lock
generally works for me.
Arthur is not implementing a general purpose thread-safe language, so
like him I continue
Arthur wrote:
-Original Message-
From: Laura Creighton [mailto:[EMAIL PROTECTED]
And I think he will like tens of thousands of threads, too,
though if these just means tens of thousands of chances to
modify only part of your complex number, when you wanted an
In a message of Thu, 23 Mar 2006 16:24:39 +0100, Grégoire Dooms writes:
Arthur wrote:
-Original Message-
From: Laura Creighton [mailto:[EMAIL PROTECTED]
And I think he will like tens of thousands of threads, too,
though if these just means tens of thousands of
Then it is the language implementor's headache to make the locking mechanism
work.
from threading import Lock
generally works for me.
Arthur is not implementing a general purpose thread-safe language, so
like him I continue to be confused as to the relevance of this
conversation to his
Since my name was invoked recently on this thread (albeit with a question
mark), let me try to summarize:
We all agree that mutability introduces interesting issues, particularly in
the face of true concurrency. Language designers are very interested in
languages with semantics that avoid or
Christian Mascher wrote:
Scott David Daniels wrote:
copying to a minimum. With immutables, you needn't do any of the
bookkeeping. It is not that you have gone terribly wrong; it is that
you have opened the lid on a large class of avoidable problems. If you
look at Java's strings (as I
In a message of Tue, 21 Mar 2006 13:58:52 CST, Michael Tobis writes:
While PyPy is a most admirable endeavor, I can't imagine that it can
resolve this problem. I'll be most pleased to discover that I am
wrong, so please correct me.
Is scientific programming a target usage of PyPy?
Yes.
In
-Original Message-
From: Laura Creighton [mailto:[EMAIL PROTECTED]
We don't -- at least right now -- want to replace these
cases where you use numeric because you really need a lot of
linear algebra.
Actually, the way I see it, there will be a significant benefit even when
From: Michael Tobis [mailto:[EMAIL PROTECTED]
Note that when you stray from pure python you shrink your
user base and complicate your support issues substantially.
Haven't had the opportunity to code much anew, but am still replaying to
myself where I am with these issues, and in the
I use numeric a lot, and I understand what you mean.
Perhaps there is some Python-like scientific language yet to be
invented, but on the other hand, perhaps the interface between
convenient latent typing and efficient strong typing may be fated to
always be a bit uncomfortable.
Meanwhile I have
Arthur,
have you tried using Psyco?
Then you get to write your code in a naive, straightforward
fashion, and then you get something that runs nearly as fast.
Plus no headaches from having to write your code inside out,
like numeric makes you do, all too often.
Laura, sold on it,
In a message
In a message of Tue, 21 Mar 2006 11:17:42 CST, Michael Tobis writes:
I use numeric a lot, and I understand what you mean.
Perhaps there is some Python-like scientific language yet to be
invented, but on the other hand, perhaps the interface between
convenient latent typing and efficient strong
-Original Message-
From: Michael Tobis [mailto:[EMAIL PROTECTED]
Sent: Tuesday, March 21, 2006 12:18 PM
To: Arthur; edu-sig@python.org
Subject: Re: [Edu-sig] Properties use case
If you want to beat me to the
punch read this thread (if you dare):
http://mail.python.org
Arthur wrote:
The small problem at the moment being the laptop on which I have my latest
working version ain't taking well to getting powered up.
ARG.,
Laptops are, in my experience fragile little beasties.
So, this discussion has led me to think about a structure like:
-Original Message-
From: [EMAIL PROTECTED]
[mailto:[EMAIL PROTECTED] On Behalf Of kirby urner
Sent: Sunday, March 19, 2006 10:58 AM
Arthur is a really smart guy --
knows enough to get himself in real trouble.
And generally have.
Just a little more cautious, with age,
-Original Message-
From: [EMAIL PROTECTED]
[mailto:[EMAIL PROTECTED]
On Behalf Of Scott David Daniels
What got me thinking about this was why would you want to
share mutable state on complexes (and then on points) --
the answer is when you are applying a uniform
Arthur wrote:
... But if we trace back the thread we will see that the bottom line question
that I was struggling with at the beginning was precisely the question of
what *makes* a primitive type such. Obviously something much deeper than the
fact that it is coded in C.
Well, if it hadn't
-Original Message-
From: [EMAIL PROTECTED]
[mailto:[EMAIL PROTECTED] On Behalf Of Arthur
Sent: Saturday, March 18, 2006 1:39 PM
To: 'Scott David Daniels'; edu-sig@python.org
I don't understand, really, the distinction
between a vector expressed as a list and a vector expressed
In a message of Sat, 18 Mar 2006 14:11:03 EST, Arthur writes:
-Original Message-
From: [EMAIL PROTECTED]
[mailto:[EMAIL PROTECTED] On Behalf Of Arthur
Sent: Saturday, March 18, 2006 1:39 PM
To: 'Scott David Daniels'; edu-sig@python.org
I don't understand, really, the distinction
-Original Message-
From: Laura Creighton [mailto:[EMAIL PROTECTED]
Sent: Saturday, March 18, 2006 3:01 PM
To: Arthur
I'm confused too.
It sounds to me that you want to invent your own type. Does
your type have any relationship to the complex numbers that
we know and
Arthur wrote:
...
Isn't the creation of any class the creation of one's own type? Now what am
I missing now?
Ahh, I thought we were talking about language primitives. The range of
behavior for non-primitives is larger. For example, a Vertex in 3-space
for a polyhedron might have mutable
Hello Scott,
In C++ we have a saying for value types, such as complex numbers: Do
as the ints do. The complex class in C++ is also immutable. I have
never seen a need for mutable numeric, scalar quantities since I
began scientific programming 30 years ago. Just a perspective.
Friday, March 17,
-Original Message-
From: [EMAIL PROTECTED]
[mailto:[EMAIL PROTECTED] On Behalf Of Scott David Daniels
Arthur wrote:
...
Isn't the creation of any class the creation of one's own
type? Now
what am I missing now?
Ahh, I thought we were talking about language
The following, modulo a pronoun shift were exactly the words I was
sitting down to type.
I am not designing a programming language, I am designing an application.
That is why, to me, the advice offerred to date seems quite far off the mark.
And bingo - for that application I need them to be
-Original Message-
From: [EMAIL PROTECTED]
[mailto:[EMAIL PROTECTED] On Behalf Of Arthur
What was creepy - *I thought* - was the concept of
mutable complex number as a type, in the same sense that any
class is a type.
Just so that I am not accused of being disingenuous.
-Original Message-
From: [EMAIL PROTECTED]
[mailto:[EMAIL PROTECTED] On Behalf Of Michael Tobis
objects than values.
So, is there a problem with wrapping them thus:
###
class mcx(object):
def __init__(self,val):
self.val = complex(val)
def
-Original Message-
From: Michael Tobis [mailto:[EMAIL PROTECTED]
So unless there's a performance issue I can't see what you
lose by wrapping the complex number.
My last friend oh well.
Because it didn't *feel* yet that I couldn't come up with something better,
that I was at
-Original Message-
From: Arthur [mailto:[EMAIL PROTECTED]
Because it didn't *feel* yet that I couldn't come up with
something better, that I was at the end of the road. No
question, it was workable - and if I was being paid to do
this work by the hour it would have been
Well, if you are sacrificing performance, what is wrong with wrapping
the complex number in a pure python class with all the magic methods
overridden?
I share your objectives and agree that Python provides a platform for
addressing them. See my article at
-Original Message-
From: Michael Tobias [mailto:[EMAIL PROTECTED]
I would be happy to discuss the topic, but this requires
that I approach the design with due skepticism. If you don't
care to explain your needs you can't expect many useful
answers, though I think it's
On Saturday 18 March 2006 16:39, Michael Tobis wrote:
So, is there a problem with wrapping them thus:
###
class mcx(object):
def __init__(self,val):
self.val = complex(val)
def __add__(self,other):
and similarly for most other special methods
return
This reminds me of a question I have with new-style classes.
I just asked basically this question on c.l.p, and Alex Martelli has
answered, quite helpfully. See topic
can't rebind magic methods'
Michael Tobis
___
Edu-sig mailing list
- Original Message -
From: kirby urner [EMAIL PROTECTED]
Date: Thursday, March 16, 2006 9:38 pm
Subject: Re: [Edu-sig] Properties use case
Well, philosophically, I could see where a lot of CS types might have
a problem with mutable numbers, complex or otherwise.
Are you a CS type
Arthur:
Are you a CS type? If so, speak directly.
I'm a CS type (BS in CS, MS in CSEE). Kirby's right, it's generally
considered better to return a new primitive type rather than mutate
it in place. Many programming languages impose striction
functionality which means you have no (or nearly
- Original Message -
From: Dethe Elza [EMAIL PROTECTED]
Date: Friday, March 17, 2006 6:08 pm
Subject: Re: [Edu-sig] Properties use case
Arthur:
Are you a CS type? If so, speak directly.
I'm a CS type (BS in CS, MS in CSEE). Kirby's right, it's generally
considered better
- Original Message -
From: Dethe Elza [EMAIL PROTECTED]
What defines a primitive type. My understanding is that in many
languages there
is no complex primitive type.
Each language defines its own primitive types, some have no primitive
types (or hide them better), some are
Obviously once I become convinced that the mutable complex numbers happens
to work for my purposes, there is nothing preventing me from implementing
as an extension in C.
Of course.
Would that put the issue to bed?
No particular issue. Kirby said something, you challenged it, I'm
putting
- Original Message -
From: Dethe Elza [EMAIL PROTECTED]
Yes, I know, I read that. I'm not questioning that you know this.
You asked what problems from a CS viewpoint there would be. I told
you. You don't like it, don't ask.
Its not that I'm a bad guy.
Must be that I'm just
[EMAIL PROTECTED] wrote:
Instead of having my geometric objects of the complex plane *be* complex
numbes,
there is certainly the solution of having a complex number as an attribute of
these objects -
and then I can take more your approach, and at the speed of C, since I would
then
be
Thank you for a refreshingly terse and substantive comment! Let's have
more of those!
mt
On 3/17/06, Scott David Daniels [EMAIL PROTECTED] wrote:
[EMAIL PROTECTED] wrote:
Instead of having my geometric objects of the complex plane *be* complex
numbes,
there is certainly the solution of
On 3/17/06, Dethe Elza [EMAIL PROTECTED] wrote:
Nope, perfectly willing to be shown otherwise. On the other hand,
folks have dropped off the list, or threatened to, in part because of
your attacks on other posters.
My interest in justice has overwhelmed my interest in discretion. I
have
-Original Message-
From: [EMAIL PROTECTED]
[mailto:[EMAIL PROTECTED] On Behalf Of Scott David Daniels
So, that's why CS people like immutable primitive types.
I believe you.
But if we trace back the thread we will see that the bottom line question
that I was struggling with
- Original Message -
From: kirby urner [EMAIL PROTECTED]
Date: Thursday, March 16, 2006 5:04 pm
Subject: Re: [Edu-sig] Properties use case
The idea of a mutable complex number gives me the creeps. Did you
say you'd seen this successfully tried somewhere?
Don't lose any sleep over
The idea of a mutable complex number gives me the creeps. Did you
say you'd seen this successfully tried somewhere?
Don't lose any sleep over it.
Yes.
PyGeo.
Art
Sorry you felt forced into doing something quirky for whatever reason.
Or maybe it's just for the fun of it,
kirby urner wrote:
I am sure I am taking at least a bit of a performance hit by going this
route. Does anyone see something simple I may be missing here to get to
where I am trying to get, without the hit?
Art
Sounds like the kind of question that should go with example code, but
maybe
A Numeric array is mutable; it refers to allocated memory. So any
subpart of it is mutable. So I suggest you use a 1-element complex
numeric array as your mutable complex type.
import Numeric as N
a = N.ones((20,20),N.Complex)
b = N.ravel(a[1:2,1:2])
b
array([ 1.+0.j])
id(b)
2741696
b += 1
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