Simplified interpolations

Made dea3 more robust
master
Per.Andreas.Brodtkorb 10 years ago
parent d221e9f7d9
commit 18a50edb23

@ -81,7 +81,7 @@ def dea3(v0, v1, v2):
smalle2 = (abs(ss * E1) <= 1.0e-3).ravel()
result = 1.0 * E2
abserr = err1 + err2 + E2 * _EPS * 10.0
abserr = err1 + err2 + abs(E2) * _EPS * 10.0
converged = (err1 <= tol1) & (err2 <= tol2).ravel() | smalle2
k4, = (1 - converged).nonzero()
if k4.size > 0:

@ -4,11 +4,8 @@ import numpy as np
import scipy.signal
# import scipy.sparse.linalg # @UnusedImport
import scipy.sparse as sparse
from numpy.ma.core import ones, zeros, prod, sin
from numpy import diff, pi, inf # @UnresolvedImport
from numpy.lib.shape_base import vstack
from numpy.lib.function_base import linspace
from scipy.interpolate import PiecewisePolynomial
from numpy import ones, zeros, prod, sin, diff, pi, inf, vstack, linspace
from scipy.interpolate import PiecewisePolynomial, interp1d
import polynomial as pl
@ -323,17 +320,11 @@ class PPform(object):
indxs = indxs.clip(0, len(self.breaks))
pp = self.coeffs
dx = xx - self.breaks.take(indxs)
if True:
v = pp[0, indxs]
for i in xrange(1, self.order):
v = dx * v + pp[i, indxs]
values = v
else:
V = np.vander(dx, N=self.order)
# values = np.diag(dot(V,pp[:,indxs]))
dot = np.dot
values = np.array([dot(V[k, :], pp[:, indxs[k]])
for k in xrange(len(xx))])
res[mask] = values
res.shape = saveshape
@ -1060,6 +1051,46 @@ class Pchip(PiecewisePolynomial):
super(Pchip, self).__init__(x, zip(y, yp), orders=3)
def interp3(x, y, z, v, xi, yi, zi, method='cubic'):
"""Interpolation on 3-D. x, y, xi, yi should be 1-D
and z.shape == (len(x), len(y), len(z))"""
q = (x, y, z)
qi = (xi, yi, zi)
for j in range(3):
pp = interp1d(q[j], v, axis=j, kind=method)
v = pp(qi[j])
return v
def somefunc(x, y, z):
return x**2 + y**2 - z**2 + x*y*z
def test_interp3():
# some input data
x = np.linspace(0, 1, 5)
y = np.linspace(0, 2, 6)
z = np.linspace(0, 3, 7)
v = somefunc(x[:, None, None], y[None, :, None], z[None, None, :])
# interpolate
xi = np.linspace(0, 1, 45)
yi = np.linspace(0, 2, 46)
zi = np.linspace(0, 3, 47)
vi = interp3(x, y, z, v, xi, yi, zi)
import matplotlib.pyplot as plt
X, Y = np.meshgrid(xi, yi)
plt.figure(1)
plt.subplot(1, 2, 1)
plt.pcolor(X, Y, vi[:, :, 12].T)
plt.title('interpolated')
plt.subplot(1, 2, 2)
plt.pcolor(X, Y, somefunc(xi[:, None], yi[None, :], zi[12]).T)
plt.title('exact')
plt.show('hold')
def test_smoothing_spline():
x = linspace(0, 2 * pi + pi / 4, 20)
y = sin(x) # + np.random.randn(x.size)
@ -1074,7 +1105,7 @@ def test_smoothing_spline():
import matplotlib.pyplot as plb
plb.plot(x, y, x1, y1, '.', x1, dy1, 'ro', x1, y01, 'r-')
plb.show()
plb.show('hold')
pass
# tck = interpolate.splrep(x, y, s=len(x))
@ -1234,6 +1265,7 @@ def test_docstrings():
if __name__ == '__main__':
# test_func()
# test_doctstrings()
# test_smoothing_spline()
test_smoothing_spline()
# compare_methods()
demo_monoticity()
# demo_monoticity()
# test_interp3()

@ -2130,7 +2130,7 @@ def dea3(v0, v1, v2):
smallE2 = (abs(ss * E1) <= 1.0e-3).ravel()
result = 1.0 * E2
abserr = err1 + err2 + E2 * _EPS * 10.0
abserr = err1 + err2 + abs(E2) * _EPS * 10.0
converged = (err1 <= tol1) & (err2 <= tol2).ravel() | smallE2
k4, = (1 - converged).nonzero()
if k4.size > 0:

@ -22,7 +22,7 @@ from plotbackend import plotbackend as plt
import numpy as np
from numpy.fft import fft, ifft
from numpy import (zeros, ones, zeros_like, array, asarray, newaxis, arange,
logical_or, any, pi, cos, round, diff, all, exp,
logical_or, any, pi, cos, round, diff, all, exp, atleast_1d,
where, extract, linalg, sign, concatenate, floor, isreal,
conj, remainder, linspace, sum)
from numpy.lib.polynomial import * # @UnusedWildImport

@ -11,7 +11,9 @@ from scipy.misc.doccer import inherit_docstring_from
from scipy import special
from scipy import optimize
from scipy import integrate
from scipy.special import (gammaln as gamln, gamma as gam, boxcox, boxcox1p, log1p, expm1)
from scipy.special import (gammaln as gamln, gamma as gam, boxcox, boxcox1p,
log1p, expm1)
#inv_boxcox, inv_boxcox1p)
from numpy import (where, arange, putmask, ravel, sum, shape,
log, sqrt, exp, arctanh, tan, sin, arcsin, arctan,

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