Scheme_Object *scheme_rational_power(const Scheme_Object *o, const Scheme_Object *p)
{
double b, e, v;
if (((Scheme_Rational *)p)->denom == one) {
Scheme_Object *a[2], *n;
a[0] = ((Scheme_Rational *)o)->num;
a[1] = ((Scheme_Rational *)p)->num;
n = scheme_expt(2, a);
a[0] = ((Scheme_Rational *)o)->denom;
return make_rational(n, scheme_expt(2, a), 0);
}
if (scheme_is_rational_positive(o)) {
b = scheme_rational_to_double(o);
e = scheme_rational_to_double(p);
v = pow(b, e);
#ifdef USE_SINGLE_FLOATS_AS_DEFAULT
return scheme_make_float(v);
#else
return scheme_make_double(v);
#endif
} else {
return scheme_complex_power(scheme_real_to_complex(o),
scheme_real_to_complex(p));
}
}
Scheme_Object *scheme_complex_sqrt(const Scheme_Object *o)
{
Scheme_Complex *c = (Scheme_Complex *)o;
Scheme_Object *r, *i, *ssq, *srssq, *nrsq, *prsq, *nr, *ni;
r = c->r;
i = c->i;
if (scheme_is_zero(i)) {
/* Special case for x+0.0i: */
r = scheme_sqrt(1, &r);
if (!SCHEME_COMPLEXP(r))
return scheme_make_complex(r, i);
else {
c = (Scheme_Complex *)r;
if (SAME_OBJ(c->r, zero)) {
/* need an inexact-zero real part: */
#ifdef MZ_USE_SINGLE_FLOATS
if (SCHEME_FLTP(c->i))
r = scheme_make_float(0.0);
else
#endif
r = scheme_make_double(0.0);
return scheme_make_complex(r, c->i);
} else
return r;
}
}
ssq = scheme_bin_plus(scheme_bin_mult(r, r),
scheme_bin_mult(i, i));
srssq = scheme_sqrt(1, &ssq);
if (SCHEME_FLOATP(srssq)) {
/* We may have lost too much precision, if i << r. The result is
going to be inexact, anyway, so switch to using expt. */
Scheme_Object *a[2];
a[0] = (Scheme_Object *)o;
a[1] = scheme_make_double(0.5);
return scheme_expt(2, a);
}
nrsq = scheme_bin_div(scheme_bin_minus(srssq, r),
scheme_make_integer(2));
nr = scheme_sqrt(1, &nrsq);
if (scheme_is_negative(i))
nr = scheme_bin_minus(zero, nr);
prsq = scheme_bin_div(scheme_bin_plus(srssq, r),
scheme_make_integer(2));
ni = scheme_sqrt(1, &prsq);
return scheme_make_complex(ni, nr);
}
