[section pow]

[section Rationale]

Computing the power of a number with an exponent that is fixed and known in advance is a common
need for programmers. In such cases, the usual method is to avoid the overhead implied by the
pow, powf and powl C functions by hardcoding the expression:

[h4]

    // Hand-written 8th power of a 'base' variable

    double result = base*base*base*base*base*base*base*base;

However, this kind of expression is not really readable (knowing the value of the exponent involves
counting the number of occurences of 'base'), error-prone (it's easy to forget an occurence),
syntactically bulky, and non-optimal in terms of performance.

The pow function of Boost.Math helps writing this kind expression along with solving all the
problems listed above:

[h4]

    // 8th power of a 'base' variable using math::pow

    double result = pow<8>(base);

The expression is now shorter, easier to read, safer, and even faster. Indeed, pow will compute the
expression such that only log2(N) products are made for a power of N. For instance in the example
above, the resulting expression will be the same as if we had written this, with only one
computation of each identical subexpression :

[h4]

    // Internal effect of pow<8>(base)

    double result = ((base*base)*(base*base))*((base*base)*(base*base));

Only 3 different products were actually computed.

[endsect]

[section Header File]

This function can be used by including [@../../boost/math/pow.hpp pow.hpp].

[endsect]

[section Synopsis]

[h4]
    namespace boost {
    namespace math {

    template <int N, typename T>
    double pow(T base);

    }
    }

[endsect]

[section Acknowledgements]

Thanks to Joaquín López Muñoz and Scott McMurray for their help in improving the implementation.

[endsect]

[endsect]