Re: [Python-Dev] Python 2.6.4rc2
Barry Warsaw python.org> writes: > http://www.python.org/download/releases/2.6.4/ Good news, but just one little nit: the page above appears to link to the NEWS file for 2.6.4rc1. Regards, Vinay Sajip ___ Python-Dev mailing list Python-Dev@python.org http://mail.python.org/mailman/listinfo/python-dev Unsubscribe: http://mail.python.org/mailman/options/python-dev/archive%40mail-archive.com
Re: [Python-Dev] SIGCHECK() in longobject.c
On Sun, Oct 18, 2009 at 11:46 PM, Antoine Pitrou wrote: > Sure, but it's no different than doing, e.g.: > list(range(1)).sort() > > (don't try this, it just made by computer slow down to a crawl and I had to > kill > -9 the Python interpreter) Maybe you were running out of RAM? On a 64-bit machine, list(range(10**8)) takes over 3 Gb. For me, x = list(range(10**8)) takes around 6 seconds, and then x.sort() takes around 2 seconds. This is on a machine with 16 Gb of RAM. (Though I do seem to recall that timsort is extra fast for already sorted lists: O(n) rather than O(n log n)?) So I'd say that it *is* different. A million digit integer takes less than half a megabyte of RAM, so a single operation can be horribly slow long before memory limitations are reached. I'd prefer to keep the SIGCHECK unless there's a really compelling advantage to getting rid of it. Mark ___ Python-Dev mailing list Python-Dev@python.org http://mail.python.org/mailman/listinfo/python-dev Unsubscribe: http://mail.python.org/mailman/options/python-dev/archive%40mail-archive.com
Re: [Python-Dev] Python 2.6.4rc2
On Oct 19, 2009, at 3:59 AM, Vinay Sajip wrote: Barry Warsaw python.org> writes: http://www.python.org/download/releases/2.6.4/ Good news, but just one little nit: the page above appears to link to the NEWS file for 2.6.4rc1. Ooops! Fixed, thanks. -Barry PGP.sig Description: This is a digitally signed message part ___ Python-Dev mailing list Python-Dev@python.org http://mail.python.org/mailman/listinfo/python-dev Unsubscribe: http://mail.python.org/mailman/options/python-dev/archive%40mail-archive.com
Re: [Python-Dev] SIGCHECK() in longobject.c
On Sun, Oct 18, 2009 at 9:01 PM, Antoine Pitrou wrote:
> Can we remove this check, or are there people doing million-digits
> calculations
> they want to interrupt using Control-C ?
By the way, here's an example of an *almost* real-life use of million digit
calculations.
For an elementary number theory course that I taught a while ago, there
was an associated (optional) computer lab, where the students used
Python to investigate various ideas, conjectures, examples, etc. One
of the less open-ended questions might have been[1] something like:
"On August 23rd, 2008 a computer at UCLA found the first example
of a prime with more than 10 million digits: p = 2**43112609-1. Find
(1) the exact number of digits in p, when written out in decimal
(2) the last 100 digits of p
(3) the first 100 digits of p."
It's wonderfully easy to get answers to these questions with Python:
>>> import math
>>> e = 43112609
>>> p = 2**e - 1
>>> ndigits = int(math.ceil(math.log10(p)))
>>> last_100_digits = '{:0100d}'.format(p % 10**100)
>>> first_100_digits = str(p // 10**(ndigits-100))
Getting the first 100 digits takes a good few seconds; the
other operations are faster.
But if you (not unreasonably) try to compute str(p),
you'll find it's impossibly slow, and it's very handy
that it's possible to interrupt that calculation, attempt
to understand *why* it's slow, and then try different
methods.
(And yes, there are better ways to get both the first
and last hundred digits.)
Mark
[1] Might have been, but wasn't. Hence the *almost*. If I'd been
teaching that course this semester I'd almost certainly have included
something like this.
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Re: [Python-Dev] Proposal : Python Trusted Computing API
On Sun, Oct 18, 2009 at 11:29 PM, Abhiram Kasina wrote: > Trusted Computing (TC) is a technology developed and promoted by the Trusted > Computing Group (TCG)[3]. So, basically the group came up with these chips > called TPM chips which are present on most motherboards nowadays. The main > purpose of it is to enhance security so that infected executables don't run. > It also provides memory curtaining such that cryptographic keys won't be > accessible and many other features. There was a criticism on this from the > FOSS community as well that it enables DRM. No wonder, it is being pushed by > Intel, Microsoft, AMD, etc.. But personally I think its a good idea from > security point of view. Hm... Given that most infections these days are JavaScript based and run in the browser, how does this provide any protection? I'm presuming you're going to say that it doesn't but that there are other use cases where it *does* provide protection; but most likely those use cases are only relevant for Windows (since that's what most attackers attack anyway). > So, currently there is an TSS (TCG Software Stack)[1] API written in C. And > TrustedJava[2] is a project which ported it to Java and is going to be > included in the standard API of Java soon. They have 2 versions of it. One > is a simple wrapper on top of the API and the other is a whole > implementation of the stack in Java. Since this intefaces with the hardware, doesn't it require some kind of cooperation from the Linux kernel? And wouldn't it be better if Python was never allowed access to any of the protected resources in the first place? > My proposal is we create an API for it in python. > Reason: I am a developer in Umit Where/what is Umit? (Google gives several meanings but it's unclear which you might mean.) > and I think Python is a very good platform > for developing applications. So, why not create an API which helps in > developing secure applications? You'd first have to tell us more about the security model. What is a "secure application" and what does it protect against? And how? > I would love to learn more and provide you with any more information. Please > let me know what you guys think of it? This is better directed at python-ideas, so I've redirected this reply there and Bcc'ed the python-dev list. > Thanks in advance > > Cheers > Abhiram > > [1] > http://www.trustedcomputinggroup.org/resources/tcg_software_stack_tss_specification > [2] http://trustedjava.sourceforge.net/index.php?item=jtss/about > [3] http://www.trustedcomputinggroup.org/ > > ___ > Python-Dev mailing list > Python-Dev@python.org > http://mail.python.org/mailman/listinfo/python-dev > Unsubscribe: > http://mail.python.org/mailman/options/python-dev/guido%40python.org > > -- --Guido van Rossum (home page: http://www.python.org/~guido/) ___ Python-Dev mailing list Python-Dev@python.org http://mail.python.org/mailman/listinfo/python-dev Unsubscribe: http://mail.python.org/mailman/options/python-dev/archive%40mail-archive.com
Re: [Python-Dev] Proposal : Python Trusted Computing API
Abhiram Kasina wrote: > I would love to learn more and provide you with any more information. > Please let me know what you guys think of it? This is really an off-topic question for python-dev. This list is just about developing the core interpreter and standard library - we have no control over the APIs that people choose to develop and publish on top of that. If you want to develop such an API and put it up on PyPI, then go right ahead. comp.lang.python (aka python-list) would be the place to ask for interest from other developers. Regards, Nick. -- Nick Coghlan | ncogh...@gmail.com | Brisbane, Australia --- ___ Python-Dev mailing list Python-Dev@python.org http://mail.python.org/mailman/listinfo/python-dev Unsubscribe: http://mail.python.org/mailman/options/python-dev/archive%40mail-archive.com
[Python-Dev] Add const to python API - issue 6952
http://bugs.python.org/issue6952 Martin v. Löwis suggested that solutions to this issue should be discussed here. My goal is to avoid compiler warning and the need to cast to remove const when calling the python API. For example I see compiler messages like this on Mac OS X Snow Leopard g++ reports: example.cxx:633: warning: deprecated conversion from string constant to ‘char*’ The patch I developed for comment only adds const to the input parameters and used casts to allow output parameters to stay without the const. This is because adding the const to the input params will not break existing code, but adding const to output parameters may well require code changes for users of the Python API. What is the best approach to this problem that will be acceptable? Barry ___ Python-Dev mailing list Python-Dev@python.org http://mail.python.org/mailman/listinfo/python-dev Unsubscribe: http://mail.python.org/mailman/options/python-dev/archive%40mail-archive.com
Re: [Python-Dev] SIGCHECK() in longobject.c
[Mark Dickinson] > By the way, here's an example of an *almost* real-life use of million digit > calculations. > > For an elementary number theory course that I taught a while ago, there > was an associated (optional) computer lab, where the students used > Python to investigate various ideas, conjectures, examples, etc. One > of the less open-ended questions might have been[1] something like: > > "On August 23rd, 2008 a computer at UCLA found the first example > of a prime with more than 10 million digits: p = 2**43112609-1. Find > > (1) the exact number of digits in p, when written out in decimal > (2) the last 100 digits of p > (3) the first 100 digits of p." > > It's wonderfully easy to get answers to these questions with Python: ... > But if you (not unreasonably) try to compute str(p), > you'll find it's impossibly slow, and it's very handy > that it's possible to interrupt that calculation, attempt > to understand *why* it's slow, and then try different > methods. Don't want to hijack this thread, but this is the kind of use case justifying keeping the 3-argument pow in the decimal module. People "playing" with number theory questions can learn a bag of tricks to worm around that non-decimal arithmetic can make it inconvenient & slow to get answers about decimal digits, but most people -- and especially beginners -- find life easier when doing calculations in decimal to begin with. Then they can use obvious methods, and not get sidetracked by wondering why they take forever to finish. Although, to be fair, I started >>> decimal.getcontext().prec = 2000 >>> p10 = pow(decimal.Decimal(2), 43112609) before I started typing this, and am still waiting for it to finish ;-) OTOH, >>> decimal.getcontext().prec = 200 >>> pow(decimal.Decimal(2), 43112609) # get the first 100 digits (& then some) and >>> pow(decimal.Decimal(2), 43112609, 10**100) - 1 # get the last 100 digits both appear to work instantaneously. ___ Python-Dev mailing list Python-Dev@python.org http://mail.python.org/mailman/listinfo/python-dev Unsubscribe: http://mail.python.org/mailman/options/python-dev/archive%40mail-archive.com
Re: [Python-Dev] Python 2.6.4rc2
I'm getting this warning. It seems nothing is actually broken, but the fix is pretty easy. gcc -pthread -c -fno-strict-aliasing -g -Wall -Wstrict-prototypes -I. -IInclude -I./Include -DPy_BUILD_CORE -o Objects/unicodeobject.o Objects/unicodeobject.c Objects/unicodeobject.c: In function 'PyUnicodeUCS2_FromFormatV': Objects/unicodeobject.c:687: warning: pointer targets in passing argument 1 of 'strlen' differ in signedness /usr/include/string.h:397: note: expected 'const char *' but argument is of type 'unsigned char *' Objects/unicodeobject.c:687: warning: pointer targets in passing argument 1 of 'PyUnicodeUCS2_DecodeUTF8' differ in signedness Include/unicodeobject.h:752: note: expected 'const char *' but argument is of type 'unsigned char *' BTW, should Python build with a C++ compiler? It seems this is not possible with 2.6.4rc2 (and GCC 4.4.1) On Mon, Oct 19, 2009 at 8:55 AM, Barry Warsaw wrote: > On Oct 19, 2009, at 3:59 AM, Vinay Sajip wrote: > >> Barry Warsaw python.org> writes: >> >>> http://www.python.org/download/releases/2.6.4/ >> >> Good news, but just one little nit: the page above appears to link to the >> NEWS >> file for 2.6.4rc1. > > Ooops! Fixed, thanks. > -Barry > > > ___ > Python-Dev mailing list > Python-Dev@python.org > http://mail.python.org/mailman/listinfo/python-dev > Unsubscribe: > http://mail.python.org/mailman/options/python-dev/dalcinl%40gmail.com > > -- Lisandro Dalcín --- Centro Internacional de Métodos Computacionales en Ingeniería (CIMEC) Instituto de Desarrollo Tecnológico para la Industria Química (INTEC) Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET) PTLC - Güemes 3450, (3000) Santa Fe, Argentina Tel/Fax: +54-(0)342-451.1594 ___ Python-Dev mailing list Python-Dev@python.org http://mail.python.org/mailman/listinfo/python-dev Unsubscribe: http://mail.python.org/mailman/options/python-dev/archive%40mail-archive.com
Re: [Python-Dev] Add const to python API - issue 6952
> The patch I developed for comment only adds const to the input > parameters and used casts to > allow output parameters to stay without the const. What specific APIs are you talking about here? Regards, Martin ___ Python-Dev mailing list Python-Dev@python.org http://mail.python.org/mailman/listinfo/python-dev Unsubscribe: http://mail.python.org/mailman/options/python-dev/archive%40mail-archive.com
