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@ -5,8 +5,9 @@ from numpy import pi, sqrt, ones, zeros # @UnresolvedImport
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from scipy import integrate as intg
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import scipy.special.orthogonal as ort
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from scipy import special as sp
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from .plotbackend import plotbackend as plt
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from scipy.integrate import simps, trapz
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from .plotbackend import plotbackend as plt
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from .demos import humps
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from .misc import dea3
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from .dctpack import dct
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@ -48,9 +49,9 @@ def clencurt(fun, a, b, n0=5, trace=False, args=()):
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Example
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-------
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>>> import numpy as np
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>>> val,err = clencurt(np.exp,0,2)
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>>> abs(val-np.expm1(2))< err, err<1e-10
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(array([ True], dtype=bool), array([ True], dtype=bool))
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>>> val, err = clencurt(np.exp, 0, 2)
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>>> np.allclose(val, np.expm1(2)), err[0] < 1e-10
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(True, True)
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See also
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@ -103,24 +104,20 @@ def clencurt(fun, a, b, n0=5, trace=False, args=()):
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f[0, :] = f[0, :] / 2
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f[n, :] = f[n, :] / 2
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# % x = cos(pi*0:n/n)
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# % f = f(x)
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# %
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# % N+1
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# % c(k) = (2/N) sum f''(n)*cos(pi*(2*k-2)*(n-1)/N), 1 <= k <= N/2+1.
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# % n=1
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# x = cos(pi*0:n/n)
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# f = f(x)
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#
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# N+1
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# c(k) = (2/N) sum f''(n)*cos(pi*(2*k-2)*(n-1)/N), 1 <= k <= N/2+1.
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# n=1
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fft = np.fft.fft
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tmp = np.real(fft(f[:n, :], axis=0))
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c = 2 / n * (tmp[0:n / 2 + 1, :] + np.cos(np.pi * s2) * f[n, :])
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c[0, :] = c[0, :] / 2
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c[n / 2, :] = c[n / 2, :] / 2
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# % alternative call
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# c2 = dct(f)
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c = c[0:n / 2 + 1, :] / ((s2 - 1) * (s2 + 1))
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Q = (af - bf) * np.sum(c, axis=0)
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# Q = (a-b).*sum( c(1:n/2+1,:)./repmat((s2-1).*(s2+1),1,Na))
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abserr = (bf - af) * np.abs(c[n / 2, :])
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@ -238,9 +235,9 @@ def h_roots(n, method='newton'):
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Example
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-------
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>>> import numpy as np
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>>> [x,w] = h_roots(10)
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>>> np.sum(x*w)
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-5.2516042729766621e-19
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>>> x, w = h_roots(10)
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>>> np.allclose(np.sum(x*w), -5.2516042729766621e-19)
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True
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See also
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--------
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@ -451,7 +448,7 @@ def la_roots(n, alpha=0, method='newton'):
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>>> import numpy as np
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>>> [x,w] = h_roots(10)
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>>> np.sum(x*w)
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-5.2516042729766621e-19
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1.3352627380516791e-17
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See also
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--------
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@ -555,9 +552,9 @@ def p_roots(n, method='newton', a=-1, b=1):
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-------
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Integral of exp(x) from a = 0 to b = 3 is: exp(3)-exp(0)=
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>>> import numpy as np
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>>> [x,w] = p_roots(11,a=0,b=3)
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>>> np.sum(np.exp(x)*w)
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19.085536923187668
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>>> x, w = p_roots(11, a=0, b=3)
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>>> np.allclose(np.sum(np.exp(x)*w), 19.085536923187668)
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True
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See also
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--------
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@ -723,15 +720,22 @@ def qrule(n, wfun=1, alpha=0, beta=0):
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Examples:
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---------
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>>> import numpy as np
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# integral of x^2 from a = -1 to b = 1
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>>> [bp,wf] = qrule(10)
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>>> sum(bp**2*wf) # integral of x^2 from a = -1 to b = 1
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0.66666666666666641
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>>> np.allclose(sum(bp**2*wf), 0.66666666666666641)
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True
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# integral of exp(-x.^2)*x.^2 from a = -inf to b = inf
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>>> [bp,wf] = qrule(10,2)
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>>> sum(bp**2*wf) # integral of exp(-x.^2)*x.^2 from a = -inf to b = inf
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0.88622692545275772
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>>> np.allclose(sum(bp**2*wf), 0.88622692545275772)
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True
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# integral of (x+1)*(1-x)^2 from a = -1 to b = 1
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>>> [bp,wf] = qrule(10,4,1,2)
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>>> (bp*wf).sum() # integral of (x+1)*(1-x)^2 from a = -1 to b = 1
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0.26666666666666755
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>>> np.allclose((bp*wf).sum(), 0.26666666666666755)
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True
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See also
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--------
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@ -841,23 +845,24 @@ class _Gaussq(object):
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---------
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integration of x**2 from 0 to 2 and from 1 to 4
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>>> from scitools import numpyutils as npt
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>>> A = [0, 1]; B = [2,4]
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>>> fun = npt.wrap2callable('x**2')
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>>> [val1,err1] = gaussq(fun,A,B)
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>>> val1
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array([ 2.6666667, 21. ])
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>>> err1
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array([ 1.7763568e-15, 1.0658141e-14])
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>>> import numpy as np
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>>> A = [0, 1]
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>>> B = [2, 4]
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>>> fun = lambda x: x**2
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>>> val1, err1 = gaussq(fun,A,B)
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>>> np.allclose(val1, [ 2.6666667, 21. ])
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True
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>>> np.allclose(err1, [ 1.7763568e-15, 1.0658141e-14])
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True
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Integration of x^2*exp(-x) from zero to infinity:
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>>> fun2 = npt.wrap2callable('1')
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>>> val2, err2 = gaussq(fun2, 0, npt.inf, wfun=3, alpha=2)
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>>> val3, err3 = gaussq(lambda x: x**2,0, npt.inf, wfun=3, alpha=0)
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>>> val2, err2
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(array([ 2.]), array([ 6.6613381e-15]))
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>>> val3, err3
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(array([ 2.]), array([ 1.7763568e-15]))
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>>> fun2 = lambda x : np.ones(np.shape(x))
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>>> val2, err2 = gaussq(fun2, 0, np.inf, wfun=3, alpha=2)
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>>> val3, err3 = gaussq(lambda x: x**2,0, np.inf, wfun=3, alpha=0)
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>>> np.allclose(val2, 2), err2[0] < 1e-14
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(True, True)
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>>> np.allclose(val3, 2), err3[0] < 1e-14
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(True, True)
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Integrate humps from 0 to 2 and from 1 to 4
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>>> val4, err4 = gaussq(humps,A,B)
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@ -1024,23 +1029,29 @@ class _Quadgr(object):
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--------
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>>> import numpy as np
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>>> Q, err = quadgr(np.log,0,1)
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>>> quadgr(np.exp,0,9999*1j*np.pi)
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(-2.0000000000122662, 2.1933237448479304e-09)
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>>> q, err = quadgr(np.exp,0,9999*1j*np.pi)
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>>> np.allclose(q, -2.0000000000122662), err < 1.0e-08
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(True, True)
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>>> quadgr(lambda x: np.sqrt(4-x**2),0,2,1e-12)
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(3.1415926535897811, 1.5809575870662229e-13)
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>>> q, err = quadgr(lambda x: np.sqrt(4-x**2), 0, 2, abseps=1e-12)
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>>> np.allclose(q, 3.1415926535897811), err < 1.0e-12
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(True, True)
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>>> quadgr(lambda x: x**-0.75,0,1)
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(4.0000000000000266, 5.6843418860808015e-14)
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>>> q, err = quadgr(lambda x: x**-0.75, 0, 1)
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>>> np.allclose(q, 4), err < 1.e-13
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(True, True)
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>>> quadgr(lambda x: 1./np.sqrt(1-x**2),-1,1)
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(3.141596056985029, 6.2146261559092864e-06)
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>>> q, err = quadgr(lambda x: 1./np.sqrt(1-x**2), -1, 1)
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>>> np.allclose(q, 3.141596056985029), err < 1.0e-05
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(True, True)
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>>> quadgr(lambda x: np.exp(-x**2),-np.inf,np.inf,1e-9) #% sqrt(pi)
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(1.7724538509055152, 1.9722334876348668e-11)
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>>> q, err = quadgr(lambda x: np.exp(-x**2), -np.inf, np.inf, 1e-9)
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>>> np.allclose(q, np.sqrt(np.pi)), err < 1e-9
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(True, True)
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>>> quadgr(lambda x: np.cos(x)*np.exp(-x),0,np.inf,1e-9)
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(0.50000000000000044, 7.3296813063450372e-11)
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>>> q, err = quadgr(lambda x: np.cos(x)*np.exp(-x), 0, np.inf, 1e-9)
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>>> np.allclose(q, 0.5), err < 1e-9
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(True, True)
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See also
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--------
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