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 __abs__(self): return C.Abs(self)