def test_legroots(self) :
assert_almost_equal(leg.legroots([1]), [])
assert_almost_equal(leg.legroots([1, 2]), [-.5])
for i in range(2, 5) :
tgt = np.linspace(-1, 1, i)
res = leg.legroots(leg.legfromroots(tgt))
assert_almost_equal(trim(res), trim(tgt))
def test_legroots(self) :
assert_almost_equal(leg.legroots([1]), [])
assert_almost_equal(leg.legroots([1, 2]), [-.5])
for i in range(2,5) :
tgt = np.linspace(-1, 1, i)
res = leg.legroots(leg.legfromroots(tgt))
assert_almost_equal(trim(res), trim(tgt))
def weights_roots(order, rules='Gauss-Lobatto'):
c_leg = [1] if order == 0 else [i//order for i in xrange(order+1)]
c_dleg = lgd.legder(c_leg)
if rules == 'Gauss-Lobatto':
xs = np.array( [-1] + list( lgd.legroots(c_dleg) ) + [1] )
ws = 2 / ( order * (order + 1) * (lgd.legval(xs, c_leg)**2) )
elif rules == 'Gauss-Legendre':
xs = lgd.legroots(c_leg)
ws = 2 / ( (1 - xs**2) * (lgd.legval(xs, c_dleg)**2) )
return xs, ws
def _legendre_roots(self, c): r""" Compute the roots of the scaled and shifted Legendre polynomial """ lam = legroots(c) lam = self._inverse_transform(lam) return lam
def make_grid(self):
import numpy as np
from numpy.polynomial.legendre import legder, legroots, legval
N = self._N
self.NN = N + 1
L = self.L
factor = L / 2
d1 = np.zeros((N + 1, N + 1))
cp = legder([0] * N + [1])
zg = np.hstack([-1.0, legroots(cp), 1.0])
P_N = legval(zg, [0] * N + [1])
with np.errstate(divide='ignore'):
d1 = P_N[:, None] / (P_N[None, :] * (zg[:, None] - zg[None, :]))
d1[np.diag_indices(N + 1)] = 0.0
d1[0, 0] = -N * (N + 1) / 4
d1[N, N] = +N * (N + 1) / 4
d2 = np.dot(d1, d1)
self.zg = (zg + 1) * L / 2 + self.zmin
self.d0 = np.eye(self.NN)
self.d1 = d1 / factor
self.d2 = d2 / factor**2
# Call other objects that depend on the grid
for callback in self._observers:
callback()
def GL_Quad_2D(integrand, lowZ, upZ, lowPhi, upPhi, N, args):
#Weight Function
def weight(arg):
w = (2.0 * (1 - (arg**2))) / (
(N * (Legendre(arg, N - 1) - arg * Legendre(arg, N)))**2)
return w
#Create list of roots for P_N
rootIndex = np.zeros(N + 1)
rootIndex[N] = 1
roots = legroots(rootIndex)
#Equally spaced points for trapzeoidal integration method for phi
Npoints = 100
deltaPhi = (upPhi - lowPhi) / Npoints
phiVals = np.linspace(lowPhi, upPhi, Npoints + 1)
value = 0
for z_i in roots:
phiValue = 0
for phi in phiVals:
phiValue = (deltaPhi) * integrand(
((upZ - lowZ) / 2.0) * z_i +
((upZ + lowZ) / 2.0), phi, *args) + phiValue
value = weight(z_i) * phiValue + value
value = ((upZ - lowZ) / 2.0) * value
return value
def _getNodes(self):
"""
Computes Gauss-Lobatto integration nodes.
Calculates the Gauss-Lobatto integration nodes via a root calculation of derivatives of the legendre
polynomials. Note that the precision of float 64 is not guarantied.
Copyright by Dieter Moser, 2014
Returns:
np.ndarray: array of Gauss-Lobatto nodes
"""
M = self.num_nodes
a = self.tleft
b = self.tright
roots = leg.legroots(
leg.legder(np.array([0] * (M - 1) + [1], dtype=np.float64)))
nodes = np.array(np.append([-1.0], np.append(roots, [1.0])),
dtype=np.float64)
nodes = (a * (1 - nodes) + b * (1 + nodes)) / 2
return nodes
def GL_Quad(integrand, lowerBound, upperBound, N, args):
#Weight Function
def weight(x):
w = (2.0 * (1 -
(x**2))) / ((N *
(Legendre(x, N - 1) - x * Legendre(x, N)))**2)
return w
#Create list of roots for P_N
rootIndex = np.zeros(N + 1)
rootIndex[N] = 1
roots = legroots(rootIndex)
value = 0
for x_i in roots:
value = weight(x_i) * integrand(
((upperBound - lowerBound) / 2.0) * x_i +
((upperBound + lowerBound) / 2.0), *args) + value
value = ((upperBound - lowerBound) / 2.0) * value
return value
# def test(x, N, fn):
# val = np.cos(x)
# return val
#
# def randomness(x):
# return 0
#
# Nval = 10
# integralValue = GL_Quad(test, -3, 3, 20, args=(10, randomness,))
# print integralValue - 2*np.sin(3)
def roots(order):
coef = []
for n in range(0, order+1):
if n == order:
coef.append(1)
else:
coef.append(0)
return .5*(leg.legroots(coef) + 1)
def quad_custom(fun, n=10):
P_n = [0 for i in range(1, n)] + [1]
P_n_roots = leg.legroots(P_n)
d_P_n = leg.legder(P_n)
d_P_n_vals = leg.legval(P_n_roots, d_P_n)
weights = 2 / ((1 - np.power(P_n_roots, 2)) * np.power(d_P_n_vals, 2))
result = np.sum(weights * fun(P_n_roots))
return result
def test_collocation_points_legendre_gauss(self):
for num_coll_points in range(2, 13):
coefs = np.zeros(num_coll_points + 1)
coefs[-1] = 1.
coll_points_numpy = legendre.legroots(coefs)
mesh = Mesh1D(num_coll_points, Basis.Legendre, Quadrature.Gauss)
coll_points_spectre = collocation_points(mesh)
np.testing.assert_allclose(coll_points_numpy, coll_points_spectre,
1e-12, 1e-12)
def defFluxPoints(n):
res = np.zeros(n)
res[0] = -1.0
res[-1] = 1.0
coeff = np.zeros(n - 1)
coeff[-1] = 1.0
roots = leg.legroots(coeff)
for i in range(1, n - 1):
res[i] = roots[i - 1]
return res
def leg_roots_vec():
roots = {}
# loop over all degrees up to MAXD
for i in range(0, MAXD):
c = np.zeros(MAXD)
c[i] = 1
r = leg.legroots(c)
roots.update({i: r})
return roots
def _compute_nodes(self):
"""Computes Gauss-Lobatto integration nodes.
Calculates the Gauss-Lobatto integration nodes via a root calculation of derivatives of the legendre
polynomials.
Note that the precision of float 64 is not guarantied.
"""
roots = leg.legroots(leg.legder(np.array([0] * (self.num_nodes - 1) +
[1], dtype=np.float64)))
self._nodes = np.array(np.append([-1.0], np.append(roots, [1.0])),
dtype=np.float64)
def GaussQuad(f, xi, xf, n, M):
I = 0
c = np.append(np.zeros(M), 1)
x = lg.legroots(c)
w = 0 * x
d = lg.legder(c)
for i in range(len(x)):
w[i] = 2. / ((1 - x[i]**2) * (lg.legval(x[i], d))**2)
for i in range(M):
I += w[i] * f(n, interval(x[i], xf, xi))
I *= 0.5 * (xf - xi)
return I
def get_leg_scalfac(deg):
testpt = 0.5
c = np.zeros(MAXD)
c[deg] = 1
val = leg.legval(testpt, c, tensor=False)
r = leg.legroots(c)
prod = 1
for root in r:
prod = prod * (testpt - root)
scalfac = val / prod
return scalfac
def get_leg_roots():
roots = {}
# loop over all degrees up to MAXD
for i in range(0, MAXD):
c = np.zeros(MAXD)
c[i] = 1
r = leg.legroots(c)
roots.update({i: r})
# save roots to file
w = csv.writer(open(LEGF, "w"))
for key, val in roots.items():
w.writerow([key, val])
return
def gauss_lobatto_points(start, stop, num_points):
r"""Get the node points for Gauss-Lobatto quadrature.
Using :math:`n` points, this quadrature is accurate to degree
:math:`2n - 3`. The node points are :math:`x_1 = -1`,
:math:`x_n = 1` and the interior are :math:`n - 2` roots of
:math:`P'_{n - 1}(x)`.
Though we don't compute them here, the weights are
:math:`w_1 = w_n = \frac{2}{n(n - 1)}` and for the interior points
.. math::
w_j = \frac{2}{n(n - 1) \left[P_{n - 1}\left(x_j\right)\right]^2}
This is in contrast to the scheme used in Gaussian quadrature, which
use roots of :math:`P_n(x)` as nodes and use the weights
.. math::
w_j = \frac{2}{\left(1 - x_j\right)^2
\left[P'_n\left(x_j\right)\right]^2}
.. note::
This method is **not** generic enough to accommodate non-NumPy
types as it relies on the :mod:`numpy.polynomial.legendre`.
:type start: float
:param start: The beginning of the interval.
:type stop: float
:param stop: The end of the interval.
:type num_points: int
:param num_points: The number of points to use.
:rtype: :class:`numpy.ndarray`
:returns: 1D array, the interior quadrature nodes.
"""
p_n_minus1 = [0] * (num_points - 1) + [1]
inner_nodes = legendre.legroots(legendre.legder(p_n_minus1))
# Utilize symmetry about 0.
inner_nodes = 0.5 * (inner_nodes - inner_nodes[::-1])
if start != -1.0 or stop != 1.0:
# [-1, 1] --> [0, 2] --> [0, stop - start] --> [start, stop]
inner_nodes = start + (inner_nodes + 1.0) * 0.5 * (stop - start)
return np.hstack([[start], inner_nodes, [stop]])
def _getNodes(self):
"""
Copyright by Dieter Moser, 2014
Computes Gauss-Lobatto integration nodes.
Calculates the Gauss-Lobatto integration nodes via a root calculation of derivatives of the legendre
polynomials. Note that the precision of float 64 is not guarantied.
"""
M = self.num_nodes
a = self.tleft
b = self.tright
roots = leg.legroots(leg.legder(np.array([0] * (M - 1) + [1], dtype=np.float64)))
nodes = np.array(np.append([-1.0], np.append(roots, [1.0])), dtype=np.float64)
nodes = (a * (1 - nodes) + b * (1 + nodes)) / 2
return nodes
def GL_Quad_2D(integrand, lowZ, upZ, lowPhi, upPhi, N, round, args):
if round == 1:
def conformalFactor(z, phi):
return 1
elif round == 0:
def conformalFactor(z, phi):
return psi4(z, phi)
#Weight Function
def weight(arg):
w = (2.0 * (1 - (arg**2))) / (
(N * (Legendre(arg, N - 1) - arg * Legendre(arg, N)))**2)
return w
#Create list of roots for P_N
rootIndex = np.zeros(N + 1)
rootIndex[N] = 1
roots = legroots(rootIndex)
#Equally spaced points for trapzeoidal integration method for phi
Npoints = 100
deltaPhi = (upPhi - lowPhi) / Npoints
phiVals = np.linspace(lowPhi, upPhi - deltaPhi, Npoints)
# Zpoints = 1000
# deltaZ = (upZ-lowZ)/Zpoints
# Zvals = np.linspace(lowZ, upZ, Zpoints+1)
# ztracker = 0
value = 0
for z_i in roots:
phiValue = 0
for phi in phiVals:
phiValue = deltaPhi * conformalFactor(z_i, phi) * integrand(
((upZ - lowZ) / 2.0) * z_i +
((upZ + lowZ) / 2.0), phi, *args) + phiValue
value = weight(z_i) * phiValue + value
value = ((upZ - lowZ) / 2.0) * value
return value
def GL_Quad(integrand, lowerBound, upperBound, N, args):
#Weight Function
def weight(x):
w = (2.0 * (1 -
(x**2))) / ((N *
(Legendre(x, N - 1) - x * Legendre(x, N)))**2)
return w
#Create list of roots for P_N
rootIndex = np.zeros(N + 1)
rootIndex[N] = 1
roots = legroots(rootIndex)
value = 0
for x_i in roots:
value = weight(x_i) * integrand(
((upperBound - lowerBound) / 2.0) * x_i +
((upperBound + lowerBound) / 2.0), *args) + value
value = ((upperBound - lowerBound) / 2.0) * value
return value
def legroots(cs):
from numpy.polynomial.legendre import legroots
return legroots(cs)
from scipy.interpolate import interp1d
Nin = 10 # Number of data points in
Nout = 50 # Number of points we want to project onto
Nfine = Nin**2 # Number of points for plotting pretty
Xin = np.linspace(-1,1,Nin) # The space of points
Fin = np.cos(20*Xin)+np.sin(7*Xin) # Evaluate some fake data
Xfine = np.linspace(-1,1,Nfine) # Linspace for plotting pretty
Fspline = interp1d(Xin,Fin,kind='cubic') # A spline interpolation of the data
Xout = np.linspace(-1,1,Nout-1) # Probably don't need this since we want to plot at the GLL nodes
I = np.eye(Nout) # A hack for choosing the right polynomial orders
zero = np.zeros(Nout-1)
# Build our set of GLL nodes
pts = legendre.legroots(legendre.legder(I[-1])) # GLL points
Xi = [-1, list(pts), 1]
Xi = np.hstack(Xi)
#print "GLL Points:", Xi
# Build the weight set
weights = np.zeros([len(Xi)])
for i in range(len(Xi)-2):
weights[i+1] = 2/((Nout)*(Nout-1)*(legendre.legval(Xi[i+1],I[-1]))**2)
weights[0]=2.0/((Nout)*(Nout-1))
weights[-1]=weights[0]
#print "GLL Weights:", weights
# Calculate the norms
norms = np.zeros(Nout)
a = -1
b = 1
"""something special only for you"""
print("We have a function:\nf(x)=P(n,x)*P(m,x)")
N = int(input("Enter n for the above function"))
M = int(input("Enter m for the above function"))
print("Degree of f(x)=", N + M)
#no. of steps
n = int(
input("enter N so that degree of f(x) is smaller than equal to 2N-1\t"))
"""finding roots of nth legendre polynomial and storing it in t"""
Q = []
for i in range(n):
Q.append(0)
Q.append(1)
t = leg.legroots(Q)
#print(t)
#solution finding
sol = 0
for i in range(n):
u = ((b - a) / 2) * t[i] + (a + b) / 2
#print(u)
#weight
w = 2 * (1 - t[i]**2) / (((n + 1)**2) * (P(n + 1, t[i]))**2)
#print(w)
sol1 = w * func(N, M, u)
sol = sol + sol1
#solution Found
main_sol = (b - a) * sol / 2
def lagrange(N, x0=x0, x1=x1, C_a=1.3, C_f=1.0, grid='cheb0'):
#x = np.linspace(x0, x1, N+1)
if grid == 'cheb0':
dummy = np.zeros(N)
dummy[-1] = 1
x = np.sort(np.array(cheb.chebroots(dummy).tolist() + [-1, 1]))
x = 0.5 * (x1 - x0) * x + 0.5 * (x1 + x0)
if grid == 'cheb1':
dummy = np.zeros(N + 1)
dummy[-1] = 1
x = np.sort(
np.array(cheb.chebroots(cheb.chebder(dummy)).tolist() + [-1, 1]))
x = 0.5 * (x1 - x0) * x + 0.5 * (x1 + x0)
if grid == 'legendre0':
dummy = np.zeros(N)
dummy[-1] = 1
x = np.sort(np.array(leg.legroots(dummy).tolist() + [-1, 1]))
x = 0.5 * (x1 - x0) * x + 0.5 * (x1 + x0)
if grid == 'legendre1':
dummy = np.zeros(N + 1)
dummy[-1] = 1
x = np.sort(
np.array(leg.legroots(leg.legder(dummy)).tolist() + [-1, 1]))
x = 0.5 * (x1 - x0) * x + 0.5 * (x1 + x0)
#x = 0.5*(x1-x0)*np.cos( np.pi / N * np.arange(N,-1,-1) )+ 0.5*(x1+x0)
#x = 0.5*(x1-x0)*np.cos( np.pi / (N+1) * ( np.arange(N+1,0,-1) -0.5) )+ 0.5*(x1+x0)
xx, yy = np.meshgrid(x, x)
AA = yy - xx
AA[AA == 0] = 1
a = np.prod(AA, axis=1)
#mth lagrangian polynomial
def phi(y, m):
"""Evaluates m-th Lagrangian polynomial at point y"""
return np.prod((y - x)[np.arange(len(x)) != m]) / a[m]
np.seterr(all='ignore')
D = 1 / AA
np.seterr(all='raise')
D = D - np.diag(np.diag(D))
D_diag = np.diag(np.sum(D, axis=1))
D = np.multiply(np.multiply(D.T, a).T, 1 / a) + D_diag
#Initialization of nonlinear part
Uxy = np.zeros([N + 1, N + 1, N + 1])
#Integration matrix for integrals of between x_k and x_N
#W1 = np.zeros( [N+1, N+1] )
#Integration matrix for integrals of between x_0 and x_k
for kk in xrange(N + 1):
for ii in xrange(N + 1):
#if kk<=ii:
#W1[kk, ii] = quad(phi, x[kk] , x[-1] , args=(ii,) )[0]
if kk >= ii:
#W2[kk, ii] = quad(phi, x[0] , x[kk] , args=(ii,) )[0]
dummy = x[kk] - x[ii] - xx
dummy[np.diag_indices(N + 1)] = 1
Uxy[kk, ii, :] = np.prod(dummy, axis=1) / a
#Aggregation in
a_ker = np.vectorize(partial(agg_kernel, C_a=C_a))
Ain = 0.5 * a_ker(yy - xx, xx)
Ain[0] = 0
#Aggregation out
Aout = a_ker(yy, xx - yy)
Aout[-1] = 0
#Initialization of fragmentation in
frag = np.vectorize(partial(fragmentation, C_f=C_f))
Fin = gam(yy, xx)
Fin[-1] = 0
Fin = np.multiply(Fin, frag(x))
#Fin[np.diag_indices(N+1)]*=0.5
return x, D, Fin, Ain, Aout, Uxy
def legroots(cs):
from numpy.polynomial.legendre import legroots
return legroots(cs)
#
exec(open('common_imports.py').read())
from utils.weighted_orthpoly_solver import orthpoly_coef
import numpy.polynomial.chebyshev as cheb
import numpy.polynomial.legendre as lege
# For getting orthogonal polynomial coefficients.
n_poly_order = 100
V = orthpoly_coef(None, 'legendre', n_poly_order)
#x_sample = sin( pi * (-n_poly_order/2 + arange(n_poly_order+1))/(n_poly_order+1) )
x_sample = lege.legroots(1 * (arange(n_poly_order + 2) == n_poly_order + 1))
get_fq_coef = lambda f: np.linalg.solve(V, f(x_sample))
#get_fq_coef = lambda f: orthpoly_coef(f, 'legendre', n_poly_order)
#get_fq_coef = lambda f: cheb.Chebyshev.interpolate(f, n_poly_order).coef
#
act_fun = 'tanh'
cost_l = lambda pm: cost_flat(ans_xy, pm, layer_dims, active_function=act_fun)
cost_g = ag.jacobian(cost_l)
cost_h = ag.hessian(cost_l)
# ANN function
ann_theta_x = lambda pm, x: np.squeeze(
net_predict(x, wb_flat2layers(pm, layer_dims), active_function=act_fun))
ann_g = ag.jacobian(ann_theta_x, argnum=0)
ann_h = ag.hessian(ann_theta_x, argnum=0)
# value for parameters and input
layer_dims = [1, 2000, 1]
