int
mpc_acosh (mpc_ptr rop, mpc_srcptr op, mpc_rnd_t rnd)
{
/* acosh(z) =
NaN + i*NaN, if z=0+i*NaN
-i*acos(z), if sign(Im(z)) = -
i*acos(z), if sign(Im(z)) = +
http://functions.wolfram.com/ElementaryFunctions/ArcCosh/27/02/03/01/01/
*/
mpc_t a;
mpfr_t tmp;
int inex;
if (mpfr_zero_p (MPC_RE (op)) && mpfr_nan_p (MPC_IM (op)))
{
mpfr_set_nan (MPC_RE (rop));
mpfr_set_nan (MPC_IM (rop));
return 0;
}
/* Note reversal of precisions due to later multiplication by i or -i */
mpc_init3 (a, MPC_PREC_IM(rop), MPC_PREC_RE(rop));
if (mpfr_signbit (MPC_IM (op)))
{
inex = mpc_acos (a, op,
RNDC (INV_RND (MPC_RND_IM (rnd)), MPC_RND_RE (rnd)));
/* change a to -i*a, i.e., -y+i*x to x+i*y */
tmp[0] = MPC_RE (a)[0];
MPC_RE (a)[0] = MPC_IM (a)[0];
MPC_IM (a)[0] = tmp[0];
MPFR_CHANGE_SIGN (MPC_IM (a));
inex = MPC_INEX (MPC_INEX_IM (inex), -MPC_INEX_RE (inex));
}
else
{
inex = mpc_acos (a, op,
RNDC (MPC_RND_IM (rnd), INV_RND(MPC_RND_RE (rnd))));
/* change a to i*a, i.e., y-i*x to x+i*y */
tmp[0] = MPC_RE (a)[0];
MPC_RE (a)[0] = MPC_IM (a)[0];
MPC_IM (a)[0] = tmp[0];
MPFR_CHANGE_SIGN (MPC_RE (a));
inex = MPC_INEX (-MPC_INEX_IM (inex), MPC_INEX_RE (inex));
}
mpc_set (rop, a, rnd);
mpc_clear (a);
return inex;
}
static PyObject *
_GMPy_MPC_Acos(PyObject *x, CTXT_Object *context)
{
MPC_Object *result = NULL;
CHECK_CONTEXT(context);
if (!(result = GMPy_MPC_New(0, 0, context))) {
return NULL;
}
result->rc = mpc_acos(result->c, MPC(x), GET_MPC_ROUND(context));
_GMPy_MPC_Cleanup(&result, context);
return (PyObject*)result;
}
