Re: [PHP-DEV] ext-random: add random_float() ?
2022年12月20日(火) 18:14 Go Kudo :
> 2022年12月20日(火) 17:15 Hans Henrik Bergan :
>
>> btw while we're on the topic, does anyone know if this function gives
>> biased results/is-safe or not? i honestly don't know:
>> function random_float(float $min, float $max): float
>> {
>> if ($min > $max) throw new \InvalidArgumentException("min must be
>> less than max");
>> if ($min === $max) return $min;
>> return $min + random_int(0, PHP_INT_MAX) / PHP_INT_MAX * ($max -
>> $min);
>> }
>>
>>
>> On Tue, 20 Dec 2022 at 09:06, Hans Henrik Bergan
>> wrote:
>> >
>> > >returns a value between 0.0 and 1.0.
>> >
>> > wouldn't it be better to follow random_int(int $min, int $max) design?
>> eg
>> > random_float(float $min, float $max): float
>> >
>> > On Tue, 20 Dec 2022 at 07:27, Go Kudo wrote:
>> > >
>> > > Hi Internals.
>> > >
>> > > Congratulations on the release of PHP 8.2.
>> > > I just recently upgraded production PHP from 7.4 to 8.1 :)
>> > >
>> > > Now that my work is done, I was thinking about a proposal for a
>> sunsetting
>> > > of existing functions for PHP 8.3 based on the features introduced in
>> > > ext-random, and I realized that there is no alternative to
>> `lcg_value()`.
>> > >
>> > > Essentially, this could be completely replaced by
>> > > Random\Randomizer::getFloat(), but there are easier `random_int()` and
>> > > `random_bytes()` functions for ints and strings.
>> > >
>> > > The Randomizer may be overkill and complicated for PHP use cases where
>> > > random number reproducibility is not required in many cases.
>> > >
>> > > So, why not add a `random_float(): float` function? This function,
>> like the
>> > > others, uses CSPRNG and returns a value between 0.0 and 1.0. This
>> behavior
>> > > is `Closed` `Closed`.
>> > >
>> > > Opinions are welcome.
>> > >
>> > > Regards,
>> > > Go Kudo
>>
>
> Hi.
>
> The dangers of generating floating-point random numbers from PHP integer
> values are explained in detail in Tim and Joshua's RFC.
>
> https://wiki.php.net/rfc/randomizer_additions
>
> I missed it at first too, and was negative about adding
> `Randomizer::getFloat()` ...
> In general, I think this problem is less noticeable and the absence of the
> random_float() function increases the likelihood of incorrect
> implementations in userland.
>
> Regards,
> Go Kudo
>
In the PHP-8.3 current development branch, you can already polyfill as
follows However, it is complicated.
```php
getFloat($min, $max,
$intervalBoundary);
}
```
Re: [PHP-DEV] ext-random: add random_float() ?
2022年12月20日(火) 17:15 Hans Henrik Bergan :
> btw while we're on the topic, does anyone know if this function gives
> biased results/is-safe or not? i honestly don't know:
> function random_float(float $min, float $max): float
> {
> if ($min > $max) throw new \InvalidArgumentException("min must be
> less than max");
> if ($min === $max) return $min;
> return $min + random_int(0, PHP_INT_MAX) / PHP_INT_MAX * ($max - $min);
> }
>
>
> On Tue, 20 Dec 2022 at 09:06, Hans Henrik Bergan
> wrote:
> >
> > >returns a value between 0.0 and 1.0.
> >
> > wouldn't it be better to follow random_int(int $min, int $max) design? eg
> > random_float(float $min, float $max): float
> >
> > On Tue, 20 Dec 2022 at 07:27, Go Kudo wrote:
> > >
> > > Hi Internals.
> > >
> > > Congratulations on the release of PHP 8.2.
> > > I just recently upgraded production PHP from 7.4 to 8.1 :)
> > >
> > > Now that my work is done, I was thinking about a proposal for a
> sunsetting
> > > of existing functions for PHP 8.3 based on the features introduced in
> > > ext-random, and I realized that there is no alternative to
> `lcg_value()`.
> > >
> > > Essentially, this could be completely replaced by
> > > Random\Randomizer::getFloat(), but there are easier `random_int()` and
> > > `random_bytes()` functions for ints and strings.
> > >
> > > The Randomizer may be overkill and complicated for PHP use cases where
> > > random number reproducibility is not required in many cases.
> > >
> > > So, why not add a `random_float(): float` function? This function,
> like the
> > > others, uses CSPRNG and returns a value between 0.0 and 1.0. This
> behavior
> > > is `Closed` `Closed`.
> > >
> > > Opinions are welcome.
> > >
> > > Regards,
> > > Go Kudo
>
Hi.
The dangers of generating floating-point random numbers from PHP integer
values are explained in detail in Tim and Joshua's RFC.
https://wiki.php.net/rfc/randomizer_additions
I missed it at first too, and was negative about adding
`Randomizer::getFloat()` ...
In general, I think this problem is less noticeable and the absence of the
random_float() function increases the likelihood of incorrect
implementations in userland.
Regards,
Go Kudo
Re: [PHP-DEV] ext-random: add random_float() ?
btw while we're on the topic, does anyone know if this function gives
biased results/is-safe or not? i honestly don't know:
function random_float(float $min, float $max): float
{
if ($min > $max) throw new \InvalidArgumentException("min must be
less than max");
if ($min === $max) return $min;
return $min + random_int(0, PHP_INT_MAX) / PHP_INT_MAX * ($max - $min);
}
On Tue, 20 Dec 2022 at 09:06, Hans Henrik Bergan wrote:
>
> >returns a value between 0.0 and 1.0.
>
> wouldn't it be better to follow random_int(int $min, int $max) design? eg
> random_float(float $min, float $max): float
>
> On Tue, 20 Dec 2022 at 07:27, Go Kudo wrote:
> >
> > Hi Internals.
> >
> > Congratulations on the release of PHP 8.2.
> > I just recently upgraded production PHP from 7.4 to 8.1 :)
> >
> > Now that my work is done, I was thinking about a proposal for a sunsetting
> > of existing functions for PHP 8.3 based on the features introduced in
> > ext-random, and I realized that there is no alternative to `lcg_value()`.
> >
> > Essentially, this could be completely replaced by
> > Random\Randomizer::getFloat(), but there are easier `random_int()` and
> > `random_bytes()` functions for ints and strings.
> >
> > The Randomizer may be overkill and complicated for PHP use cases where
> > random number reproducibility is not required in many cases.
> >
> > So, why not add a `random_float(): float` function? This function, like the
> > others, uses CSPRNG and returns a value between 0.0 and 1.0. This behavior
> > is `Closed` `Closed`.
> >
> > Opinions are welcome.
> >
> > Regards,
> > Go Kudo
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Re: [PHP-DEV] ext-random: add random_float() ?
>returns a value between 0.0 and 1.0. wouldn't it be better to follow random_int(int $min, int $max) design? eg random_float(float $min, float $max): float On Tue, 20 Dec 2022 at 07:27, Go Kudo wrote: > > Hi Internals. > > Congratulations on the release of PHP 8.2. > I just recently upgraded production PHP from 7.4 to 8.1 :) > > Now that my work is done, I was thinking about a proposal for a sunsetting > of existing functions for PHP 8.3 based on the features introduced in > ext-random, and I realized that there is no alternative to `lcg_value()`. > > Essentially, this could be completely replaced by > Random\Randomizer::getFloat(), but there are easier `random_int()` and > `random_bytes()` functions for ints and strings. > > The Randomizer may be overkill and complicated for PHP use cases where > random number reproducibility is not required in many cases. > > So, why not add a `random_float(): float` function? This function, like the > others, uses CSPRNG and returns a value between 0.0 and 1.0. This behavior > is `Closed` `Closed`. > > Opinions are welcome. > > Regards, > Go Kudo -- PHP Internals - PHP Runtime Development Mailing List To unsubscribe, visit: https://www.php.net/unsub.php
