| @cindex power function |
| @cindex integer powers |
| |
| The following functions are equivalent to the function @code{gsl_pow_int} |
| (@pxref{Small integer powers}) with an error estimate. These functions are |
| declared in the header file @file{gsl_sf_pow_int.h}. |
| |
| @deftypefun double gsl_sf_pow_int (double @var{x}, int @var{n}) |
| @deftypefunx int gsl_sf_pow_int_e (double @var{x}, int @var{n}, gsl_sf_result * @var{result}) |
| These routines compute the power @math{x^n} for integer @var{n}. The |
| power is computed using the minimum number of multiplications. For |
| example, @math{x^8} is computed as @math{((x^2)^2)^2}, requiring only 3 |
| multiplications. For reasons of efficiency, these functions do not |
| check for overflow or underflow conditions. |
| @end deftypefun |
| |
| @example |
| #include <gsl/gsl_sf_pow_int.h> |
| /* compute 3.0**12 */ |
| double y = gsl_sf_pow_int(3.0, 12); |
| @end example |
| |
