zero2

Im using c as the programming language, and the formula I have calls for s to be squared {s*s}, other than just typing s*s is there a special symbol for squaring?

s2 + p * (s - x) * (p + y)

theFez

POW(3) Linux Programmer's Manual POW(3)

NAME
pow, powf, powl - power functions

SYNOPSIS
#include <math.h>

double pow(double x, double y);

float powf(float x, float y);

long double powl(long double x, long double y);

DESCRIPTION
The pow() function returns the value of x raised to the power of y.

ERRORS
The pow() function can return the following error:

EDOM The argument x is negative and y is not an integral value. This
would result in a complex number.

CONFORMING TO
SVID 3, POSIX, BSD 4.3, ISO 9899. The float and the long double vari-
ants are C99 requirements.

SEE ALSO
sqrt(3), cbrt(3)

2002-07-27 POW(3)
(END)

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zero2

thanks for the help.

theFez

of course if you are using C++ you could overload say ^ to implement the pow function and it would be as easy as s^2 to square s. but i dont really know anything about operator overloading in C and quick searches really provided no information.

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jk777

The code is much faster if you use s*s (relatively speaking).

theFez

yeah, in the case of straight up squaring the s*s is definitely faster. but for situations where you need to raise to higher powers or to an unknown power (variable) the pow function would be better.

from what i understand there is no exponentation operator in c because few processors have exponentation instructions.

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archer

Efficiency depends on the implementation of the power raising function.
This is generally done via logarithmic operations.
So for small powers like s^2 are done much more quickly as s*s, since this is a quicker operation in itself and saves the setup for a new method call.
Once you get into higher powers, it becomes much more efficient to use logarithms, and it gives you an easy way to calculate non-integer powers.

nlong

pow = suck. Pow introduces a significant slowdown. hardocde the instruction s*s. unless you will be using an exponent other than 2.