def evalf_log(expr, prec, options):
arg = expr.args[0]
workprec = prec+10
xre, xim, xacc, _ = evalf(arg, workprec, options)
if xim:
# XXX: use get_abs etc instead
re = evalf_log(C.log(C.abs(arg, evaluate=False), evaluate=False), prec, options)
im = mpf_atan2(xim, xre or fzero, prec)
return re[0], im, re[2], prec
imaginary_term = (mpf_cmp(xre, fzero) < 0)
re = mpf_log(mpf_abs(xre), prec, round_nearest)
size = fastlog(re)
if prec - size > workprec:
# We actually need to compute 1+x accurately, not x
arg = C.Add(S.NegativeOne,arg,evaluate=False)
xre, xim, xre_acc, xim_acc = evalf_add(arg, prec, options)
prec2 = workprec - fastlog(xre)
re = mpf_log(mpf_add(xre, fone, prec2), prec, round_nearest)
re_acc = prec
if imaginary_term:
return re, mpf_pi(prec), re_acc, prec
else:
return re, None, re_acc, None
def get_abs(expr, prec, options):
re, im, re_acc, im_acc = evalf(expr, prec+2, options)
if not re:
re, re_acc, im, im_acc = im, im_acc, re, re_acc
if im:
return libmpc.mpc_abs((re, im), prec), None, re_acc, None
else:
return mpf_abs(re), None, re_acc, None
def __abs__(self):
return Real._new(mlib.mpf_abs(self._mpf_), self._prec)
def __abs__(self):
return Real._new(mlib.mpf_abs(self._mpf_), self._prec)