Re: Static power() function, to add in common_factor
on 6/12/02 12:11 AM, ravioli@softhome.net wrote:
Is there an interest into having a power() template calculating the N-th power of any number, when N is known at compile-time ?t uses the algorithm of the STL power function(), and runs between two or three times faster, and maybe could be of interest in the "
which provides run-time and compile-time evaluation of the greatest common divisor (GCD) or least common multiple (LCM)
Proposals for new libraries usually go to the regular Boost list, not this one. Besides that: What would this have to do with the common-factor library? I've never heard of a function called "power". Is it a STL function that didn't get into the standard? Are there any docs for it? How do you know what algorithm it uses?
It simply works this way, for example to have PI at exponent three : double a = power_const<3>( 3.14159)
As the single include file is very short, please apologize if I give it straight on, just to save your time and to have an idea how badly you judge my poor code ;) [TRUNCATE code]
I don't think your implementation will work for negative exponents. -- Daryle Walker Mac, Internet, and Video Game Junkie darylew AT mac DOT com
----- Original Message ----- From: Daryle Walker
Is there an interest into having a power() template calculating the N-th power of any number, when N is known at compile-time ?t uses the algorithm of the STL power function(), and runs between two or three times faster, and maybe could be of interest in the "
which provides run-time and compile-time evaluation of the greatest common divisor (GCD) or least common multiple (LCM) Proposals for new libraries usually go to the regular Boost list, not this one. Besides that: Sorry for that.
What would this have to do with the common-factor library? It's about math and compile-time calculation.
I've never heard of a function called "power". Are there any docs for it? http://www.sgi.com/tech/stl/power.html Is it a STL function that didn't get into the standard? You're right : "This function is an SGI extension; it is not part of the C++ standard."
How do you know what algorithm it uses? You can take a look at the code in the preceding link. Although the algorithm is not defined by the implementation, this is one of the fastest (Called in french "algorithme dy paysan russe").
It simply works this way, for example to have PI at exponent three : double a = power_const<3>( 3.14159) [TRUNCATE code]
I don't think your implementation will work for negative exponents. You're right. It follows the guidelines of SGI STL where it's written : "Power is generalized exponentiation: it raises the value x to the power n, where n is a non-negative integer." Anyway, the change should not be difficult.
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ravioli＠softhome.net