On 10/24/2023 7:37 PM, Grant Edwards via Python-list wrote:
On 2023-10-24, Thomas Passin via Python-list wrote:
Something less ambitious than a full proof of correctness of an
arbitrary program can sometimes be achieved. The programming team
for the Apollo moon mission developed a system whic
Agreed, Chris. There are many methods way better than the sort of RAID
architecture I supplied as AN EXAMPLE easy to understand. But even so, if a
hard disk or memory chip is fried or a nuclear bomb takes out all servers in
or near a city, you would need some truly crazy architectures with info no
On Wed, 25 Oct 2023 at 13:02, Mike H via Python-list
wrote:
> Is it possible to use lambda expression instead of defining a `Key` class?
> Something like `sorted(my_list, key = lambda x, y: x+y > y+x)`?
Look up functools.cmp_to_key.
ChrisA
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On Saturday, October 15, 2016 at 12:27:42 AM UTC-7, Peter Otten wrote:
> 38016...@gmail.com wrote:
>
> > nums=['3','30','34','32','9','5']
> > I need to sort the list in order to get the largest number string:
> > '953433230'
> >
> > nums.sort(cmp=lambda a,b: cmp(a+b, b+a), reverse=True)
> >
On Wed, 25 Oct 2023 at 12:20, AVI GROSS via Python-list
wrote:
> Consider an example of bit rot. I mean what if your CPU or hard disk has a
> location where you can write a byte and read it back multiple times and
> sometimes get the wrong result. To be really cautions, you might need your
> so
On Wed, 25 Oct 2023 at 12:11, Thomas Passin via Python-list
wrote:
> This doesn't mean that no program can ever be proven to halt, nor that
> no program can never be proven correct by formal means. Will your
> program be one of those? The answer may never come ...
Indeed, and I would go further
Whoa!
The question cannot be about whether it is possible to prove any abstract
program will be correct and especially not on real hardware that can fail in
various ways or have unexpected race conditions or interacts with other places
such as over the internet.
It has been quite well proven (
On 10/24/2023 7:15 PM, o1bigtenor wrote:
On Tue, Oct 24, 2023 at 6:09 PM Thomas Passin via Python-list
wrote:
snip
By now you have read many responses that basically say that you cannot
prove that a given program has no errors, even apart from the hardware
question. Even if it could be don
On 25/10/2023 00:08, o1bigtenor via Python-list wrote:
> So how does one test software then?
Testing is very different to proving!
As an industry we do a lot of testing at many different levels.
On bigger projects you'll find:
- Unit tests - testing small fragments of a bigger program
- Integrati
On 24/10/2023 22:51, Grant Edwards via Python-list wrote:
>>> Is there a way to verify that a program is going to do what it is
>>> supposed to do even before all the hardware has been assembled and
>>> installed and tested?
> And the specified customer requirements are usually wrong too. Sure,
>
On 2023-10-24, o1bigtenor via Python-list wrote:
> So how does one test software then?
That's what customers are for!
[Actually, that's true more often than it should be.]
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On 2023-10-24, Thomas Passin via Python-list wrote:
> Something less ambitious than a full proof of correctness of an
> arbitrary program can sometimes be achieved. The programming team
> for the Apollo moon mission developed a system which, if you would
> write your requirements in a certain wa
On Tue, Oct 24, 2023 at 6:09 PM Thomas Passin via Python-list
wrote:
>
snip
>
> By now you have read many responses that basically say that you cannot
> prove that a given program has no errors, even apart from the hardware
> question. Even if it could be done, the kind of specification that you
On Tue, Oct 24, 2023 at 5:28 PM Rob Cliffe wrote:
>
> There is no general way to prove that a program is "correct". Or even
> whether it will terminate or loop endlessly.
> These are of course theoretical statements of computer science. But
> they can be rigorously proven. (Sorry if I'm just sa
On 10/24/2023 8:22 AM, o1bigtenor via Python-list wrote:
Greetings
(Sorry for a nebulous subject but dunno how to have a short title for
a complex question.)
I have been using computers for a long time but am only beginning my
foray into the
galaxy of programming. Have done little to this point
On Tue, Oct 24, 2023 at 4:54 PM Grant Edwards via Python-list
wrote:
>
> On 2023-10-24, Dan Purgert via Python-list wrote:
> > On 2023-10-24, o1bigtenor wrote:
> >> Greetings
> >>
> >> (Sorry for a nebulous subject but dunno how to have a short title for
> >> a complex question.)
> >> [...]
> >>
> On 24 Oct 2023, at 18:25, o1bigtenor via Python-list
> wrote:
>
> Is there a way to verify that a program is going to do what it is
> supposed to do
In the general case not proven to be not possible.
Have a read about the halting problem
https://en.wikipedia.org/wiki/Halting_problem
It i
On 2023-10-24, Dan Purgert via Python-list wrote:
> On 2023-10-24, o1bigtenor wrote:
>> Greetings
>>
>> (Sorry for a nebulous subject but dunno how to have a short title for
>> a complex question.)
>> [...]
>> Is there a way to verify that a program is going to do what it is
>> supposed to do even
On 2023-10-24, o1bigtenor wrote:
> Greetings
>
> (Sorry for a nebulous subject but dunno how to have a short title for
> a complex question.)
> [...]
> Is there a way to verify that a program is going to do what it is
> supposed to do even
> before all the hardware has been assembled and installed
On 2023-10-24, o1bigtenor via Python-list wrote:
> Is there a way to verify that a program is going to do what it is
> supposed to do even before all the hardware has been assembled and
> installed and tested?
It depends on what you mean by "verify ...". If you want to prove a
program correct (
I don’t think there i a simple answer to this, although if you find something
interesting, please share.
From my experience, industry is applying variety of testing methods. Starting
from lowest level components and implementing unit tests, finishing with
end-to-end testing platforms.
https://
Il 19/10/2023 00:09, Janis Papanagnou ha scritto:
I am pondering about writing a client/server software with
websockets as communication protocol. The clients will run
in browser as Javascript programs and the server may be in
any (any sensible) programming language running standalone
to be conne
Greetings
(Sorry for a nebulous subject but dunno how to have a short title for
a complex question.)
I have been using computers for a long time but am only beginning my
foray into the
galaxy of programming. Have done little to this point besides
collection of information
on sensors and working o
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