def mpc_agm(a, b, prec, rnd=round_fast):
"""
Complex AGM.
TODO:
* check that convergence works as intended
* optimize
* select a nonarbitrary branch
"""
if mpc_is_infnan(a) or mpc_is_infnan(b):
return fnan, fnan
if mpc_zero in (a, b):
return fzero, fzero
if mpc_neg(a) == b:
return fzero, fzero
wp = prec+20
eps = mpf_shift(fone, -wp+10)
while 1:
a1 = mpc_shift(mpc_add(a, b, wp), -1)
b1 = mpc_sqrt(mpc_mul(a, b, wp), wp)
a, b = a1, b1
size = mpf_min_max([mpc_abs(a,10), mpc_abs(b,10)])[1]
err = mpc_abs(mpc_sub(a, b, 10), 10)
if size == fzero or mpf_lt(err, mpf_mul(eps, size)):
return a
def mpc_agm(a, b, prec, rnd=round_fast):
"""
Complex AGM.
TODO:
* check that convergence works as intended
* optimize
* select a nonarbitrary branch
"""
if mpc_is_infnan(a) or mpc_is_infnan(b):
return fnan, fnan
if mpc_zero in (a, b):
return fzero, fzero
if mpc_neg(a) == b:
return fzero, fzero
wp = prec + 20
eps = mpf_shift(fone, -wp + 10)
while 1:
a1 = mpc_shift(mpc_add(a, b, wp), -1)
b1 = mpc_sqrt(mpc_mul(a, b, wp), wp)
a, b = a1, b1
size = sorted([mpc_abs(a, 10), mpc_abs(a, 10)], cmp=mpf_cmp)[1]
err = mpc_abs(mpc_sub(a, b, 10), 10)
if size == fzero or mpf_lt(err, mpf_mul(eps, size)):
return a
def mpc_erf(z, prec, rnd=round_fast):
re, im = z
if im == fzero:
return (mpf_erf(re, prec, rnd), fzero)
wp = prec + 20
z2 = mpc_square(z, prec + 20)
v = mpc_hyp1f1_rat((1, 2), (3, 2), mpc_neg(z2), wp, rnd)
sqrtpi = mpf_sqrt(mpf_pi(wp), wp)
c = mpf_rdiv_int(2, sqrtpi, wp)
c = mpc_mul_mpf(z, c, wp)
return mpc_mul(c, v, prec, rnd)
def mpc_erf(z, prec, rnd=round_fast):
re, im = z
if im == fzero:
return (mpf_erf(re, prec, rnd), fzero)
wp = prec + 20
z2 = mpc_mul(z, z, prec+20)
v = mpc_hyp1f1_rat((1,2), (3,2), mpc_neg(z2), wp, rnd)
sqrtpi = mpf_sqrt(mpf_pi(wp), wp)
c = mpf_rdiv_int(2, sqrtpi, wp)
c = mpc_mul_mpf(z, c, wp)
return mpc_mul(c, v, prec, rnd)
def mpc_zeta(s, prec, rnd=round_fast, alt=0, force=False):
re, im = s
if im == fzero:
return mpf_zeta(re, prec, rnd, alt), fzero
# slow for large s
if (not force) and mpf_gt(mpc_abs(s, 10), from_int(prec)):
raise NotImplementedError
wp = prec + 20
# Near pole
r = mpc_sub(mpc_one, s, wp)
asign, aman, aexp, abc = mpc_abs(r, 10)
pole_dist = -2*(aexp+abc)
if pole_dist > wp:
if alt:
q = mpf_ln2(wp)
y = mpf_mul(q, mpf_euler(wp), wp)
g = mpf_shift(mpf_mul(q, q, wp), -1)
g = mpf_sub(y, g)
z = mpc_mul_mpf(r, mpf_neg(g), wp)
z = mpc_add_mpf(z, q, wp)
return mpc_pos(z, prec, rnd)
else:
q = mpc_neg(mpc_div(mpc_one, r, wp))
q = mpc_add_mpf(q, mpf_euler(wp), wp)
return mpc_pos(q, prec, rnd)
else:
wp += max(0, pole_dist)
# Reflection formula. To be rigorous, we should reflect to the left of
# re = 1/2 (see comments for mpf_zeta), but this leads to unnecessary
# slowdown for interesting values of s
if mpf_lt(re, fzero):
# XXX: could use the separate refl. formula for Dirichlet eta
if alt:
q = mpc_sub(mpc_one, mpc_pow(mpc_two, mpc_sub(mpc_one, s, wp),
wp), wp)
return mpc_mul(mpc_zeta(s, wp), q, prec, rnd)
# XXX: -1 should be done exactly
y = mpc_sub(mpc_one, s, 10*wp)
a = mpc_gamma(y, wp)
b = mpc_zeta(y, wp)
c = mpc_sin_pi(mpc_shift(s, -1), wp)
rsign, rman, rexp, rbc = re
isign, iman, iexp, ibc = im
mag = max(rexp+rbc, iexp+ibc)
wp2 = wp + mag
pi = mpf_pi(wp+wp2)
pi2 = (mpf_shift(pi, 1), fzero)
d = mpc_div_mpf(mpc_pow(pi2, s, wp2), pi, wp2)
return mpc_mul(a,mpc_mul(b,mpc_mul(c,d,wp),wp),prec,rnd)
n = int(wp/2.54 + 5)
n += int(0.9*abs(to_int(im)))
d = borwein_coefficients(n)
ref = to_fixed(re, wp)
imf = to_fixed(im, wp)
tre = MPZ_ZERO
tim = MPZ_ZERO
one = MPZ_ONE << wp
one_2wp = MPZ_ONE << (2*wp)
critical_line = re == fhalf
for k in xrange(n):
log = log_int_fixed(k+1, wp)
# A square root is much cheaper than an exp
if critical_line:
w = one_2wp // sqrt_fixed((k+1) << wp, wp)
else:
w = to_fixed(mpf_exp(from_man_exp(-ref*log, -2*wp), wp), wp)
if k & 1:
w *= (d[n] - d[k])
else:
w *= (d[k] - d[n])
wre, wim = mpf_cos_sin(from_man_exp(-imf * log, -2*wp), wp)
tre += (w * to_fixed(wre, wp)) >> wp
tim += (w * to_fixed(wim, wp)) >> wp
tre //= (-d[n])
tim //= (-d[n])
tre = from_man_exp(tre, -wp, wp)
tim = from_man_exp(tim, -wp, wp)
if alt:
return mpc_pos((tre, tim), prec, rnd)
else:
q = mpc_sub(mpc_one, mpc_pow(mpc_two, r, wp), wp)
return mpc_div((tre, tim), q, prec, rnd)
def mpc_ei(z, prec, rnd=round_fast, e1=False):
if e1:
z = mpc_neg(z)
a, b = z
asign, aman, aexp, abc = a
bsign, bman, bexp, bbc = b
if b == fzero:
if e1:
x = mpf_neg(mpf_ei(a, prec, rnd))
if not asign:
y = mpf_neg(mpf_pi(prec, rnd))
else:
y = fzero
return x, y
else:
return mpf_ei(a, prec, rnd), fzero
if a != fzero:
if not aman or not bman:
return (fnan, fnan)
wp = prec + 40
amag = aexp+abc
bmag = bexp+bbc
zmag = max(amag, bmag)
can_use_asymp = zmag > wp
if not can_use_asymp:
zabsint = abs(to_int(a)) + abs(to_int(b))
can_use_asymp = zabsint > int(wp*0.693) + 20
try:
if can_use_asymp:
if zmag > wp:
v = fone, fzero
else:
zre = to_fixed(a, wp)
zim = to_fixed(b, wp)
vre, vim = complex_ei_asymptotic(zre, zim, wp)
v = from_man_exp(vre, -wp), from_man_exp(vim, -wp)
v = mpc_mul(v, mpc_exp(z, wp), wp)
v = mpc_div(v, z, wp)
if e1:
v = mpc_neg(v, prec, rnd)
else:
x, y = v
if bsign:
v = mpf_pos(x, prec, rnd), mpf_sub(y, mpf_pi(wp), prec, rnd)
else:
v = mpf_pos(x, prec, rnd), mpf_add(y, mpf_pi(wp), prec, rnd)
return v
except NoConvergence:
pass
#wp += 2*max(0,zmag)
wp += 2*int(to_int(mpc_abs(z, 5)))
zre = to_fixed(a, wp)
zim = to_fixed(b, wp)
vre, vim = complex_ei_taylor(zre, zim, wp)
vre += euler_fixed(wp)
v = from_man_exp(vre,-wp), from_man_exp(vim,-wp)
if e1:
u = mpc_log(mpc_neg(z),wp)
else:
u = mpc_log(z,wp)
v = mpc_add(v, u, prec, rnd)
if e1:
v = mpc_neg(v)
return v
def mpc_ei(z, prec, rnd=round_fast, e1=False):
if e1:
z = mpc_neg(z)
a, b = z
asign, aman, aexp, abc = a
bsign, bman, bexp, bbc = b
if b == fzero:
if e1:
x = mpf_neg(mpf_ei(a, prec, rnd))
if not asign:
y = mpf_neg(mpf_pi(prec, rnd))
else:
y = fzero
return x, y
else:
return mpf_ei(a, prec, rnd), fzero
if a != fzero:
if not aman or not bman:
return (fnan, fnan)
wp = prec + 40
amag = aexp + abc
bmag = bexp + bbc
zmag = max(amag, bmag)
can_use_asymp = zmag > wp
if not can_use_asymp:
zabsint = abs(to_int(a)) + abs(to_int(b))
can_use_asymp = zabsint > int(wp * 0.693) + 20
try:
if can_use_asymp:
if zmag > wp:
v = fone, fzero
else:
zre = to_fixed(a, wp)
zim = to_fixed(b, wp)
vre, vim = complex_ei_asymptotic(zre, zim, wp)
v = from_man_exp(vre, -wp), from_man_exp(vim, -wp)
v = mpc_mul(v, mpc_exp(z, wp), wp)
v = mpc_div(v, z, wp)
if e1:
v = mpc_neg(v, prec, rnd)
else:
x, y = v
if bsign:
v = mpf_pos(x, prec, rnd), mpf_sub(y, mpf_pi(wp), prec,
rnd)
else:
v = mpf_pos(x, prec, rnd), mpf_add(y, mpf_pi(wp), prec,
rnd)
return v
except NoConvergence:
pass
#wp += 2*max(0,zmag)
wp += 2 * int(to_int(mpc_abs(z, 5)))
zre = to_fixed(a, wp)
zim = to_fixed(b, wp)
vre, vim = complex_ei_taylor(zre, zim, wp)
vre += euler_fixed(wp)
v = from_man_exp(vre, -wp), from_man_exp(vim, -wp)
if e1:
u = mpc_log(mpc_neg(z), wp)
else:
u = mpc_log(z, wp)
v = mpc_add(v, u, prec, rnd)
if e1:
v = mpc_neg(v)
return v
def mpc_zeta(s, prec, rnd=round_fast, alt=0, force=False):
re, im = s
if im == fzero:
return mpf_zeta(re, prec, rnd, alt), fzero
# slow for large s
if (not force) and mpf_gt(mpc_abs(s, 10), from_int(prec)):
raise NotImplementedError
wp = prec + 20
# Near pole
r = mpc_sub(mpc_one, s, wp)
asign, aman, aexp, abc = mpc_abs(r, 10)
pole_dist = -2 * (aexp + abc)
if pole_dist > wp:
if alt:
q = mpf_ln2(wp)
y = mpf_mul(q, mpf_euler(wp), wp)
g = mpf_shift(mpf_mul(q, q, wp), -1)
g = mpf_sub(y, g)
z = mpc_mul_mpf(r, mpf_neg(g), wp)
z = mpc_add_mpf(z, q, wp)
return mpc_pos(z, prec, rnd)
else:
q = mpc_neg(mpc_div(mpc_one, r, wp))
q = mpc_add_mpf(q, mpf_euler(wp), wp)
return mpc_pos(q, prec, rnd)
else:
wp += max(0, pole_dist)
# Reflection formula. To be rigorous, we should reflect to the left of
# re = 1/2 (see comments for mpf_zeta), but this leads to unnecessary
# slowdown for interesting values of s
if mpf_lt(re, fzero):
# XXX: could use the separate refl. formula for Dirichlet eta
if alt:
q = mpc_sub(mpc_one, mpc_pow(mpc_two, mpc_sub(mpc_one, s, wp), wp),
wp)
return mpc_mul(mpc_zeta(s, wp), q, prec, rnd)
# XXX: -1 should be done exactly
y = mpc_sub(mpc_one, s, 10 * wp)
a = mpc_gamma(y, wp)
b = mpc_zeta(y, wp)
c = mpc_sin_pi(mpc_shift(s, -1), wp)
rsign, rman, rexp, rbc = re
isign, iman, iexp, ibc = im
mag = max(rexp + rbc, iexp + ibc)
wp2 = wp + mag
pi = mpf_pi(wp + wp2)
pi2 = (mpf_shift(pi, 1), fzero)
d = mpc_div_mpf(mpc_pow(pi2, s, wp2), pi, wp2)
return mpc_mul(a, mpc_mul(b, mpc_mul(c, d, wp), wp), prec, rnd)
n = int(wp / 2.54 + 5)
n += int(0.9 * abs(to_int(im)))
d = borwein_coefficients(n)
ref = to_fixed(re, wp)
imf = to_fixed(im, wp)
tre = MPZ_ZERO
tim = MPZ_ZERO
one = MPZ_ONE << wp
one_2wp = MPZ_ONE << (2 * wp)
critical_line = re == fhalf
for k in xrange(n):
log = log_int_fixed(k + 1, wp)
# A square root is much cheaper than an exp
if critical_line:
w = one_2wp // sqrt_fixed((k + 1) << wp, wp)
else:
w = to_fixed(mpf_exp(from_man_exp(-ref * log, -2 * wp), wp), wp)
if k & 1:
w *= (d[n] - d[k])
else:
w *= (d[k] - d[n])
wre, wim = mpf_cos_sin(from_man_exp(-imf * log, -2 * wp), wp)
tre += (w * to_fixed(wre, wp)) >> wp
tim += (w * to_fixed(wim, wp)) >> wp
tre //= (-d[n])
tim //= (-d[n])
tre = from_man_exp(tre, -wp, wp)
tim = from_man_exp(tim, -wp, wp)
if alt:
return mpc_pos((tre, tim), prec, rnd)
else:
q = mpc_sub(mpc_one, mpc_pow(mpc_two, r, wp), wp)
return mpc_div((tre, tim), q, prec, rnd)
