This routine computes the power \(x^n\) for integer \(n\). The power is computed using the minimum number of multiplications. For example, \(x^8\) is computed as \(((x^2)^2)^2\), requiring only 3 multiplications. For reasons of efficiency, these functions do not check for overflow or underflow conditions.
include gsl.ampl; # compute and print 3**12 print gsl_sf_pow_int(3, 12);