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Subject: Re: [PHP-DEV] Native decimal scalar support and object types in BcMath - do we want both?
Date: Tue, 9 Apr 2024 09:01:15 +0900
Message-ID: <069A9DA0-927E-4486-BFFC-92543519F22F@sakiot.com>
References: <CAMrTa2FeSTGE9rRdeMVzULkmn4C-LQ0GC8upDtEx1JEo6A0LFA@mail.gmail.com>
Cc: "Rowan Tommins [IMSoP]" <imsop.php@rwec.co.uk>,
 internals@lists.php.net
In-Reply-To: <CAMrTa2FeSTGE9rRdeMVzULkmn4C-LQ0GC8upDtEx1JEo6A0LFA@mail.gmail.com>
To: Jordan LeDoux <jordan.ledoux@gmail.com>
From: saki@sakiot.com (Saki Takamachi)

Hi Jordan,

> To me, while being 100x to 1000x more performant at arithmetic is certainl=
y reason enough on its own, the fact that MPFR (for example) has C implement=
ations for more complex operations that can be utilized is the real selling p=
oint. The ext-stats extension hasn't been maintained since 7.4. And trig is c=
ritical for a lot of stats functions. A fairly common use of stats, even in a=
pplications you might not expect it, is to generate a Gaussian Random Number=
. That is, generate a random number where if you continued generating random=
 numbers from the same generator, they would form a normal distribution (a b=
ell curve), so the random number is weighted according to the distribution.
>=20
> The simplest way to do that is with the sin() and cos() functions (picking=
 a point on a circle). But a lot of really useful such mathematics are mainl=
y provided by libraries that ALSO provide arbitrary precision. So for instan=
ce, the Gamma Function is another very common function in statistics. To me,=
 implementing a bundled or core type that utilizes MPFR (or something simila=
r) is as much about getting access to THESE mathematical functions as it is t=
he arbitrary precision aspect.

As you say, BCMath is really barebones and slower than other libraries. It w=
ould be nice if there was a universal math extension that could handle all u=
se cases, but unfortunately there isn't one today.

The biggest problem is right there: there are several math functions, and th=
ey have slightly different characteristics.

If could combine all of these to create a new math function without sacrific=
ing the benefits of each, do you think that would be possible? (It doesn't m=
atter what libraries or technologies use internally.)

To be honest, whenever I bring up the topic of BCMath on the mailing list, t=
here are always references to speed and other libraries, so many people prob=
ably want that, but unfortunately, we probably don't have a common idea abou=
t the specifics.

If what I write is off-topic and not appropriate for this thread, I can star=
t a new thread.

Regards.

Saki=