def _vcjh_fn(self, sym):
k = self._order
eta = self._cfg.get('solver-elements-' + self.name, 'vcjh-eta')
# Expand shorthand forms of eta for common schemes
etacommon = dict(dg='0', sd='k/(k+1)', hu='(k+1)/k')
eta_k = sy.S(etacommon.get(eta, eta), locals=dict(k=k))
lkm1, lk, lkp1 = [sy.legendre_poly(m, sym) for m in [k - 1, k, k + 1]]
return (sy.S(1)/2 * (lk + (eta_k*lkm1 + lkp1)/(1 + eta_k)))
def wigner_d(l, m, m_prime, beta, wdsympy=False):
"""Computation of Wigner-d-functions for the rotation of a T-matrix
Args:
l (int): Degree :math:`l` (1, ..., lmax)
m (int): Order :math:`m` (-min(l,mmax),...,min(l,mmax))
m_prime (int): Order :math:`m_prime` (-min(l,mmax),...,min(l,mmax))
beta (float): Second Euler angle in rad
wdsympy (bool): If True, Wigner-d-functions come from the sympy toolbox
Returns:
real value of Wigner-d-function
"""
wig_d = np.zeros(l + 1, dtype=complex)
if wdsympy == False:
if beta < 0:
aa = m
bb = m_prime
m = bb
m_prime = aa
if m == 0 and m_prime == 0:
for nn in range(1, l + 1):
wig_d[nn] = sympy.legendre_poly(nn, np.cos(beta))
else:
# recursion formulation (Mishchenko, Scattering, Absorption and Emission of Light by small Particles, p.365 (B.22 - B.24))
l_min = max(abs(m), abs(m_prime))
wig_d[l_min - 1] = 0
if m_prime >= m:
zeta = 1
else:
zeta = (-1)**(m - m_prime)
wig_d[l_min] = (
zeta * 2.0**(-l_min) *
(factorial(2 * l_min) /
(factorial(abs(m - m_prime)) * factorial(abs(m + m_prime))))**
0.5 * (1 - np.cos(beta))**(abs(m - m_prime) / 2) *
(1 + np.cos(beta))**(abs(m + m_prime) / 2))
for ll in range(l_min, l):
wig_d[ll + 1] = (
((2 * ll + 1) *
(ll * (ll + 1) * np.cos(beta) - m * m_prime) * wig_d[ll] -
(ll + 1) * (ll**2 - m**2)**0.5 *
(ll**2 - m_prime**2)**0.5 * wig_d[ll - 1]) /
(ll * ((ll + 1)**2 - m**2)**0.5 *
((ll + 1)**2 - m_prime**2)**0.5))
else:
wig_d[l] = complex(Rotation.d(l, m, m_prime, beta).doit())
return wig_d[l].real
def __init__(self, npts):
# Form a suitable Legendre poly
Pn = sy.legendre_poly(npts, x)
dPn = Pn.diff()
# Roots
self.points = mp.polyroots(map(mp.mpf, sy.Poly(Pn).all_coeffs()))
# Weights
self.weights = [2/((1 - p**2)*dPn.evalf(mp.dps, subs={x: p})**2)
for p in self.points]
def test_CRootOf_eval_rational():
p = legendre_poly(4, x, polys=True)
roots = [r.eval_rational(n=18) for r in p.real_roots()]
for r in roots:
assert isinstance(r, Rational)
roots = [str(r.n(17)) for r in roots]
assert roots == [
"-0.86113631159405258",
"-0.33998104358485626",
"0.33998104358485626",
"0.86113631159405258",
]
def test_CRootOf_eval_rational():
p = legendre_poly(4, x, polys=True)
roots = [r.eval_rational(n=18) for r in p.real_roots()]
for r in roots:
assert isinstance(r, Rational)
roots = [str(r.n(17)) for r in roots]
assert roots == [
"-0.86113631159405258",
"-0.33998104358485626",
"0.33998104358485626",
"0.86113631159405258",
]
def __init__(self, npts):
# Form a suitable Legendre poly
Pn = sy.legendre_poly(npts - 1, x)
dPn = Pn.diff()
# Roots
roots = mp.polyroots(map(mp.mpf, sy.Poly(dPn).all_coeffs()))
self.points = [mp.mpf(-1)] + roots + [mp.mpf(1)]
# Weights
wts0 = mp.mpf(2)/(npts*(npts - 1))
wtsi = [2/(npts*(npts - 1)*Pn.evalf(mp.dps, subs={x: p})**2)
for p in self.points[1:-1]]
self.weights = [wts0] + wtsi + [wts0]
def test_RootOf_eval_rational():
p = legendre_poly(4, x, polys=True)
roots = [r.eval_rational(S(1) / 10**20) for r in p.real_roots()]
for r in roots:
assert isinstance(r, Rational)
# All we know is that the Rational instance will be at most 1/10^20 from
# the exact root. So if we evaluate to 17 digits, it must be exactly equal
# to:
roots = [str(r.n(17)) for r in roots]
assert roots == [
"-0.86113631159405258",
"-0.33998104358485626",
"0.33998104358485626",
"0.86113631159405258",
]
def test_RootOf_eval_rational():
p = legendre_poly(4, x, polys=True)
roots = [r.eval_rational(S(1) / 10**20) for r in p.real_roots()]
for r in roots:
assert isinstance(r, Rational)
# All we know is that the Rational instance will be at most 1/10^20 from
# the exact root. So if we evaluate to 17 digits, it must be exactly equal
# to:
roots = [str(r.n(17)) for r in roots]
assert roots == [
"-0.86113631159405258",
"-0.33998104358485626",
"0.33998104358485626",
"0.86113631159405258",
]
def max_rE_gains_3d(order, numeric=True):
"""max rE for a given order is the largest root of the order+1 Legendre
polynomial"""
x = sp.symbols('x')
lp = sp.legendre_poly(order + 1, x)
# there are more efficient methods to find the roots of the Legendre
# polynomials, but this is good enough for our purposes
# See discussion at:
# https://math.stackexchange.com/questions/12160/roots-of-legendre-polynomial
if order < 5 and not numeric:
roots = sp.roots(lp)
else:
roots = sp.nroots(lp)
# the roots can be in the keys of a dictionary or in a list,
# this works for either one
max_rE = np.max([*roots])
return [sp.legendre(n, max_rE) for n in range(order + 1)]
def test_CRootOf_evalf():
real = rootof(x**3 + x + 3, 0).evalf(n=20)
assert real.epsilon_eq(Float("-1.2134116627622296341"))
re, im = rootof(x**3 + x + 3, 1).evalf(n=20).as_real_imag()
assert re.epsilon_eq(Float("0.60670583138111481707"))
assert im.epsilon_eq(-Float("1.45061224918844152650"))
re, im = rootof(x**3 + x + 3, 2).evalf(n=20).as_real_imag()
assert re.epsilon_eq(Float("0.60670583138111481707"))
assert im.epsilon_eq(Float("1.45061224918844152650"))
p = legendre_poly(4, x, polys=True)
roots = [str(r.n(17)) for r in p.real_roots()]
# magnitudes are given by
# sqrt(3/S(7) - 2*sqrt(6/S(5))/7)
# and
# sqrt(3/S(7) + 2*sqrt(6/S(5))/7)
assert roots == [
"-0.86113631159405258",
"-0.33998104358485626",
"0.33998104358485626",
"0.86113631159405258",
]
re = rootof(x**5 - 5 * x + 12, 0).evalf(n=20)
assert re.epsilon_eq(Float("-1.84208596619025438271"))
re, im = rootof(x**5 - 5 * x + 12, 1).evalf(n=20).as_real_imag()
assert re.epsilon_eq(Float("-0.351854240827371999559"))
assert im.epsilon_eq(Float("-1.709561043370328882010"))
re, im = rootof(x**5 - 5 * x + 12, 2).evalf(n=20).as_real_imag()
assert re.epsilon_eq(Float("-0.351854240827371999559"))
assert im.epsilon_eq(Float("+1.709561043370328882010"))
re, im = rootof(x**5 - 5 * x + 12, 3).evalf(n=20).as_real_imag()
assert re.epsilon_eq(Float("+1.272897223922499190910"))
assert im.epsilon_eq(Float("-0.719798681483861386681"))
re, im = rootof(x**5 - 5 * x + 12, 4).evalf(n=20).as_real_imag()
assert re.epsilon_eq(Float("+1.272897223922499190910"))
assert im.epsilon_eq(Float("+0.719798681483861386681"))
# issue 6393
assert str(rootof(x**5 + 2 * x**4 + x**3 - 68719476736, 0).n(3)) == '147.'
eq = (531441 * x**11 + 3857868 * x**10 + 13730229 * x**9 +
32597882 * x**8 + 55077472 * x**7 + 60452000 * x**6 +
32172064 * x**5 - 4383808 * x**4 - 11942912 * x**3 - 1506304 * x**2 +
1453312 * x + 512)
a, b = rootof(eq, 1).n(2).as_real_imag()
c, d = rootof(eq, 2).n(2).as_real_imag()
assert a == c
assert b < d
assert b == -d
# issue 6451
r = rootof(legendre_poly(64, x), 7)
assert r.n(2) == r.n(100).n(2)
# issue 8617
ans = [w.n(2) for w in solve(x**3 - x - 4)]
assert rootof(exp(x)**3 - exp(x) - 4, 0).n(2) in ans
# issue 9019
r0 = rootof(x**2 + 1, 0, radicals=False)
r1 = rootof(x**2 + 1, 1, radicals=False)
assert r0.n(4) == -1.0 * I
assert r1.n(4) == 1.0 * I
# make sure verification is used in case a max/min traps the "root"
assert str(rootof(4 * x**5 + 16 * x**3 + 12 * x**2 + 7,
0).n(3)) == '-0.976'
# watch out for UnboundLocalError
c = CRootOf(90720 * x**6 - 4032 * x**4 + 84 * x**2 - 1, 0)
assert c._eval_evalf(2) # doesn't fail
# watch out for imaginary parts that don't want to evaluate
assert str(
RootOf(
x**16 + 32 * x**14 + 508 * x**12 + 5440 * x**10 + 39510 * x**8 +
204320 * x**6 + 755548 * x**4 + 1434496 * x**2 + 877969,
10).n(2)) == '-3.4*I'
assert abs(RootOf(x**4 + 10 * x**2 + 1, 0).n(2)) < 0.4
# check reset and args
r = [RootOf(x**3 + x + 3, i) for i in range(3)]
r[0]._reset()
for ri in r:
i = ri._get_interval()
n = ri.n(2)
assert i != ri._get_interval()
ri._reset()
assert i == ri._get_interval()
assert i == i.func(*i.args)
def test_RootOf_evalf():
real = RootOf(x**3 + x + 3, 0).evalf(n=20)
assert real.epsilon_eq(Float("-1.2134116627622296341"))
re, im = RootOf(x**3 + x + 3, 1).evalf(n=20).as_real_imag()
assert re.epsilon_eq(Float("0.60670583138111481707"))
assert im.epsilon_eq(-Float("1.45061224918844152650"))
re, im = RootOf(x**3 + x + 3, 2).evalf(n=20).as_real_imag()
assert re.epsilon_eq(Float("0.60670583138111481707"))
assert im.epsilon_eq(Float("1.45061224918844152650"))
p = legendre_poly(4, x, polys=True)
roots = [str(r.n(17)) for r in p.real_roots()]
assert roots == [
"-0.86113631159405258",
"-0.33998104358485626",
"0.33998104358485626",
"0.86113631159405258",
]
re = RootOf(x**5 - 5 * x + 12, 0).evalf(n=20)
assert re.epsilon_eq(Float("-1.84208596619025438271"))
re, im = RootOf(x**5 - 5 * x + 12, 1).evalf(n=20).as_real_imag()
assert re.epsilon_eq(Float("-0.351854240827371999559"))
assert im.epsilon_eq(Float("-1.709561043370328882010"))
re, im = RootOf(x**5 - 5 * x + 12, 2).evalf(n=20).as_real_imag()
assert re.epsilon_eq(Float("-0.351854240827371999559"))
assert im.epsilon_eq(Float("+1.709561043370328882010"))
re, im = RootOf(x**5 - 5 * x + 12, 3).evalf(n=20).as_real_imag()
assert re.epsilon_eq(Float("+1.272897223922499190910"))
assert im.epsilon_eq(Float("-0.719798681483861386681"))
re, im = RootOf(x**5 - 5 * x + 12, 4).evalf(n=20).as_real_imag()
assert re.epsilon_eq(Float("+1.272897223922499190910"))
assert im.epsilon_eq(Float("+0.719798681483861386681"))
# issue 6393
assert str(RootOf(x**5 + 2 * x**4 + x**3 - 68719476736, 0).n(3)) == '147.'
eq = (531441 * x**11 + 3857868 * x**10 + 13730229 * x**9 +
32597882 * x**8 + 55077472 * x**7 + 60452000 * x**6 +
32172064 * x**5 - 4383808 * x**4 - 11942912 * x**3 - 1506304 * x**2 +
1453312 * x + 512)
a, b = RootOf(eq, 1).n(2).as_real_imag()
c, d = RootOf(eq, 2).n(2).as_real_imag()
assert a == c
assert b < d
assert b == -d
# issue 6451
r = RootOf(legendre_poly(64, x), 7)
assert r.n(2) == r.n(100).n(2)
# issue 8617
ans = [w.n(2) for w in solve(x**3 - x - 4)]
assert RootOf(exp(x)**3 - exp(x) - 4, 0).n(2) in ans
# issue 9019
r0 = RootOf(x**2 + 1, 0, radicals=False)
r1 = RootOf(x**2 + 1, 1, radicals=False)
assert r0.n(4) == -1.0 * I
assert r1.n(4) == 1.0 * I
# make sure verification is used in case a max/min traps the "root"
assert str(RootOf(4 * x**5 + 16 * x**3 + 12 * x**2 + 7,
0).n(3)) == '-0.976'
def test_CRootOf_evalf():
real = rootof(x**3 + x + 3, 0).evalf(n=20)
assert real.epsilon_eq(Float("-1.2134116627622296341"))
re, im = rootof(x**3 + x + 3, 1).evalf(n=20).as_real_imag()
assert re.epsilon_eq( Float("0.60670583138111481707"))
assert im.epsilon_eq(-Float("1.45061224918844152650"))
re, im = rootof(x**3 + x + 3, 2).evalf(n=20).as_real_imag()
assert re.epsilon_eq(Float("0.60670583138111481707"))
assert im.epsilon_eq(Float("1.45061224918844152650"))
p = legendre_poly(4, x, polys=True)
roots = [str(r.n(17)) for r in p.real_roots()]
# magnitudes are given by
# sqrt(3/S(7) - 2*sqrt(6/S(5))/7)
# and
# sqrt(3/S(7) + 2*sqrt(6/S(5))/7)
assert roots == [
"-0.86113631159405258",
"-0.33998104358485626",
"0.33998104358485626",
"0.86113631159405258",
]
re = rootof(x**5 - 5*x + 12, 0).evalf(n=20)
assert re.epsilon_eq(Float("-1.84208596619025438271"))
re, im = rootof(x**5 - 5*x + 12, 1).evalf(n=20).as_real_imag()
assert re.epsilon_eq(Float("-0.351854240827371999559"))
assert im.epsilon_eq(Float("-1.709561043370328882010"))
re, im = rootof(x**5 - 5*x + 12, 2).evalf(n=20).as_real_imag()
assert re.epsilon_eq(Float("-0.351854240827371999559"))
assert im.epsilon_eq(Float("+1.709561043370328882010"))
re, im = rootof(x**5 - 5*x + 12, 3).evalf(n=20).as_real_imag()
assert re.epsilon_eq(Float("+1.272897223922499190910"))
assert im.epsilon_eq(Float("-0.719798681483861386681"))
re, im = rootof(x**5 - 5*x + 12, 4).evalf(n=20).as_real_imag()
assert re.epsilon_eq(Float("+1.272897223922499190910"))
assert im.epsilon_eq(Float("+0.719798681483861386681"))
# issue 6393
assert str(rootof(x**5 + 2*x**4 + x**3 - 68719476736, 0).n(3)) == '147.'
eq = (531441*x**11 + 3857868*x**10 + 13730229*x**9 + 32597882*x**8 +
55077472*x**7 + 60452000*x**6 + 32172064*x**5 - 4383808*x**4 -
11942912*x**3 - 1506304*x**2 + 1453312*x + 512)
a, b = rootof(eq, 1).n(2).as_real_imag()
c, d = rootof(eq, 2).n(2).as_real_imag()
assert a == c
assert b < d
assert b == -d
# issue 6451
r = rootof(legendre_poly(64, x), 7)
assert r.n(2) == r.n(100).n(2)
# issue 9019
r0 = rootof(x**2 + 1, 0, radicals=False)
r1 = rootof(x**2 + 1, 1, radicals=False)
assert r0.n(4) == -1.0*I
assert r1.n(4) == 1.0*I
# make sure verification is used in case a max/min traps the "root"
assert str(rootof(4*x**5 + 16*x**3 + 12*x**2 + 7, 0).n(3)) == '-0.976'
# watch out for UnboundLocalError
c = CRootOf(90720*x**6 - 4032*x**4 + 84*x**2 - 1, 0)
assert c._eval_evalf(2) # doesn't fail
# watch out for imaginary parts that don't want to evaluate
assert str(RootOf(x**16 + 32*x**14 + 508*x**12 + 5440*x**10 +
39510*x**8 + 204320*x**6 + 755548*x**4 + 1434496*x**2 +
877969, 10).n(2)) == '-3.4*I'
assert abs(RootOf(x**4 + 10*x**2 + 1, 0).n(2)) < 0.4
# check reset and args
r = [RootOf(x**3 + x + 3, i) for i in range(3)]
r[0]._reset()
for ri in r:
i = ri._get_interval()
n = ri.n(2)
assert i != ri._get_interval()
ri._reset()
assert i == ri._get_interval()
assert i == i.func(*i.args)
def test_RootOf_evalf():
real = RootOf(x**3 + x + 3, 0).evalf(n=20)
assert real.epsilon_eq(Float("-1.2134116627622296341"))
re, im = RootOf(x**3 + x + 3, 1).evalf(n=20).as_real_imag()
assert re.epsilon_eq(Float("0.60670583138111481707"))
assert im.epsilon_eq(-Float("1.45061224918844152650"))
re, im = RootOf(x**3 + x + 3, 2).evalf(n=20).as_real_imag()
assert re.epsilon_eq(Float("0.60670583138111481707"))
assert im.epsilon_eq(Float("1.45061224918844152650"))
p = legendre_poly(4, x, polys=True)
roots = [str(r.n(17)) for r in p.real_roots()]
assert roots == [
"-0.86113631159405258",
"-0.33998104358485626",
"0.33998104358485626",
"0.86113631159405258",
]
re = RootOf(x**5 - 5 * x + 12, 0).evalf(n=20)
assert re.epsilon_eq(Float("-1.84208596619025438271"))
re, im = RootOf(x**5 - 5 * x + 12, 1).evalf(n=20).as_real_imag()
assert re.epsilon_eq(Float("-0.351854240827371999559"))
assert im.epsilon_eq(Float("-1.709561043370328882010"))
re, im = RootOf(x**5 - 5 * x + 12, 2).evalf(n=20).as_real_imag()
assert re.epsilon_eq(Float("-0.351854240827371999559"))
assert im.epsilon_eq(Float("+1.709561043370328882010"))
re, im = RootOf(x**5 - 5 * x + 12, 3).evalf(n=20).as_real_imag()
assert re.epsilon_eq(Float("+1.272897223922499190910"))
assert im.epsilon_eq(Float("-0.719798681483861386681"))
re, im = RootOf(x**5 - 5 * x + 12, 4).evalf(n=20).as_real_imag()
assert re.epsilon_eq(Float("+1.272897223922499190910"))
assert im.epsilon_eq(Float("+0.719798681483861386681"))
# issue 6393
assert str(RootOf(x**5 + 2 * x**4 + x**3 - 68719476736, 0).n(3)) == '147.'
eq = (
531441 * x**11 + 3857868 * x**10 + 13730229 * x**9 + 32597882 * x**8 +
55077472 * x**7 + 60452000 * x**6 + 32172064 * x**5 - 4383808 * x**4 -
11942912 * x**3 - 1506304 * x**2 + 1453312 * x + 512)
a, b = RootOf(eq, 1).n(2).as_real_imag()
c, d = RootOf(eq, 2).n(2).as_real_imag()
assert a == c
assert b < d
assert b == -d
# issue 6451
r = RootOf(legendre_poly(64, x), 7)
assert r.n(2) == r.n(100).n(2)
# issue 8617
ans = [w.n(2) for w in solve(x**3 - x - 4)]
assert RootOf(exp(x)**3 - exp(x) - 4, 0).n(2) in ans
# make sure verification is used in case a max/min traps the "root"
assert str(RootOf(4 * x**5 + 16 * x**3 + 12 * x**2 + 7,
0).n(3)) == '-0.976'
