Traktor/myenv/Lib/site-packages/scipy/interpolate/tests/test_fitpack.py

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2024-05-23 01:57:24 +02:00
import itertools
import os
import numpy as np
from numpy.testing import (assert_equal, assert_allclose, assert_,
assert_almost_equal, assert_array_almost_equal)
from pytest import raises as assert_raises
import pytest
from scipy._lib._testutils import check_free_memory
from scipy.interpolate import RectBivariateSpline
from scipy.interpolate._fitpack_py import (splrep, splev, bisplrep, bisplev,
sproot, splprep, splint, spalde, splder, splantider, insert, dblint)
from scipy.interpolate.dfitpack import regrid_smth
from scipy.interpolate._fitpack2 import dfitpack_int
def data_file(basename):
return os.path.join(os.path.abspath(os.path.dirname(__file__)),
'data', basename)
def norm2(x):
return np.sqrt(np.dot(x.T, x))
def f1(x, d=0):
"""Derivatives of sin->cos->-sin->-cos."""
if d % 4 == 0:
return np.sin(x)
if d % 4 == 1:
return np.cos(x)
if d % 4 == 2:
return -np.sin(x)
if d % 4 == 3:
return -np.cos(x)
def makepairs(x, y):
"""Helper function to create an array of pairs of x and y."""
xy = np.array(list(itertools.product(np.asarray(x), np.asarray(y))))
return xy.T
class TestSmokeTests:
"""
Smoke tests (with a few asserts) for fitpack routines -- mostly
check that they are runnable
"""
def check_1(self, per=0, s=0, a=0, b=2*np.pi, at_nodes=False,
xb=None, xe=None):
if xb is None:
xb = a
if xe is None:
xe = b
N = 20
# nodes and middle points of the nodes
x = np.linspace(a, b, N + 1)
x1 = a + (b - a) * np.arange(1, N, dtype=float) / float(N - 1)
v = f1(x)
def err_est(k, d):
# Assume f has all derivatives < 1
h = 1.0 / N
tol = 5 * h**(.75*(k-d))
if s > 0:
tol += 1e5*s
return tol
for k in range(1, 6):
tck = splrep(x, v, s=s, per=per, k=k, xe=xe)
tt = tck[0][k:-k] if at_nodes else x1
for d in range(k+1):
tol = err_est(k, d)
err = norm2(f1(tt, d) - splev(tt, tck, d)) / norm2(f1(tt, d))
assert err < tol
def check_2(self, per=0, N=20, ia=0, ib=2*np.pi):
a, b, dx = 0, 2*np.pi, 0.2*np.pi
x = np.linspace(a, b, N+1) # nodes
v = np.sin(x)
def err_est(k, d):
# Assume f has all derivatives < 1
h = 1.0 / N
tol = 5 * h**(.75*(k-d))
return tol
nk = []
for k in range(1, 6):
tck = splrep(x, v, s=0, per=per, k=k, xe=b)
nk.append([splint(ia, ib, tck), spalde(dx, tck)])
k = 1
for r in nk:
d = 0
for dr in r[1]:
tol = err_est(k, d)
assert_allclose(dr, f1(dx, d), atol=0, rtol=tol)
d = d+1
k = k+1
def test_smoke_splrep_splev(self):
self.check_1(s=1e-6)
self.check_1(b=1.5*np.pi)
self.check_1(b=1.5*np.pi, xe=2*np.pi, per=1, s=1e-1)
@pytest.mark.parametrize('per', [0, 1])
@pytest.mark.parametrize('at_nodes', [True, False])
def test_smoke_splrep_splev_2(self, per, at_nodes):
self.check_1(per=per, at_nodes=at_nodes)
@pytest.mark.parametrize('N', [20, 50])
@pytest.mark.parametrize('per', [0, 1])
def test_smoke_splint_spalde(self, N, per):
self.check_2(per=per, N=N)
@pytest.mark.parametrize('N', [20, 50])
@pytest.mark.parametrize('per', [0, 1])
def test_smoke_splint_spalde_iaib(self, N, per):
self.check_2(ia=0.2*np.pi, ib=np.pi, N=N, per=per)
def test_smoke_sproot(self):
# sproot is only implemented for k=3
a, b = 0.1, 15
x = np.linspace(a, b, 20)
v = np.sin(x)
for k in [1, 2, 4, 5]:
tck = splrep(x, v, s=0, per=0, k=k, xe=b)
with assert_raises(ValueError):
sproot(tck)
k = 3
tck = splrep(x, v, s=0, k=3)
roots = sproot(tck)
assert_allclose(splev(roots, tck), 0, atol=1e-10, rtol=1e-10)
assert_allclose(roots, np.pi * np.array([1, 2, 3, 4]), rtol=1e-3)
@pytest.mark.parametrize('N', [20, 50])
@pytest.mark.parametrize('k', [1, 2, 3, 4, 5])
def test_smoke_splprep_splrep_splev(self, N, k):
a, b, dx = 0, 2.*np.pi, 0.2*np.pi
x = np.linspace(a, b, N+1) # nodes
v = np.sin(x)
tckp, u = splprep([x, v], s=0, per=0, k=k, nest=-1)
uv = splev(dx, tckp)
err1 = abs(uv[1] - np.sin(uv[0]))
assert err1 < 1e-2
tck = splrep(x, v, s=0, per=0, k=k)
err2 = abs(splev(uv[0], tck) - np.sin(uv[0]))
assert err2 < 1e-2
# Derivatives of parametric cubic spline at u (first function)
if k == 3:
tckp, u = splprep([x, v], s=0, per=0, k=k, nest=-1)
for d in range(1, k+1):
uv = splev(dx, tckp, d)
def test_smoke_bisplrep_bisplev(self):
xb, xe = 0, 2.*np.pi
yb, ye = 0, 2.*np.pi
kx, ky = 3, 3
Nx, Ny = 20, 20
def f2(x, y):
return np.sin(x+y)
x = np.linspace(xb, xe, Nx + 1)
y = np.linspace(yb, ye, Ny + 1)
xy = makepairs(x, y)
tck = bisplrep(xy[0], xy[1], f2(xy[0], xy[1]), s=0, kx=kx, ky=ky)
tt = [tck[0][kx:-kx], tck[1][ky:-ky]]
t2 = makepairs(tt[0], tt[1])
v1 = bisplev(tt[0], tt[1], tck)
v2 = f2(t2[0], t2[1])
v2.shape = len(tt[0]), len(tt[1])
assert norm2(np.ravel(v1 - v2)) < 1e-2
class TestSplev:
def test_1d_shape(self):
x = [1,2,3,4,5]
y = [4,5,6,7,8]
tck = splrep(x, y)
z = splev([1], tck)
assert_equal(z.shape, (1,))
z = splev(1, tck)
assert_equal(z.shape, ())
def test_2d_shape(self):
x = [1, 2, 3, 4, 5]
y = [4, 5, 6, 7, 8]
tck = splrep(x, y)
t = np.array([[1.0, 1.5, 2.0, 2.5],
[3.0, 3.5, 4.0, 4.5]])
z = splev(t, tck)
z0 = splev(t[0], tck)
z1 = splev(t[1], tck)
assert_equal(z, np.vstack((z0, z1)))
def test_extrapolation_modes(self):
# test extrapolation modes
# * if ext=0, return the extrapolated value.
# * if ext=1, return 0
# * if ext=2, raise a ValueError
# * if ext=3, return the boundary value.
x = [1,2,3]
y = [0,2,4]
tck = splrep(x, y, k=1)
rstl = [[-2, 6], [0, 0], None, [0, 4]]
for ext in (0, 1, 3):
assert_array_almost_equal(splev([0, 4], tck, ext=ext), rstl[ext])
assert_raises(ValueError, splev, [0, 4], tck, ext=2)
class TestSplder:
def setup_method(self):
# non-uniform grid, just to make it sure
x = np.linspace(0, 1, 100)**3
y = np.sin(20 * x)
self.spl = splrep(x, y)
# double check that knots are non-uniform
assert_(np.ptp(np.diff(self.spl[0])) > 0)
def test_inverse(self):
# Check that antiderivative + derivative is identity.
for n in range(5):
spl2 = splantider(self.spl, n)
spl3 = splder(spl2, n)
assert_allclose(self.spl[0], spl3[0])
assert_allclose(self.spl[1], spl3[1])
assert_equal(self.spl[2], spl3[2])
def test_splder_vs_splev(self):
# Check derivative vs. FITPACK
for n in range(3+1):
# Also extrapolation!
xx = np.linspace(-1, 2, 2000)
if n == 3:
# ... except that FITPACK extrapolates strangely for
# order 0, so let's not check that.
xx = xx[(xx >= 0) & (xx <= 1)]
dy = splev(xx, self.spl, n)
spl2 = splder(self.spl, n)
dy2 = splev(xx, spl2)
if n == 1:
assert_allclose(dy, dy2, rtol=2e-6)
else:
assert_allclose(dy, dy2)
def test_splantider_vs_splint(self):
# Check antiderivative vs. FITPACK
spl2 = splantider(self.spl)
# no extrapolation, splint assumes function is zero outside
# range
xx = np.linspace(0, 1, 20)
for x1 in xx:
for x2 in xx:
y1 = splint(x1, x2, self.spl)
y2 = splev(x2, spl2) - splev(x1, spl2)
assert_allclose(y1, y2)
def test_order0_diff(self):
assert_raises(ValueError, splder, self.spl, 4)
def test_kink(self):
# Should refuse to differentiate splines with kinks
spl2 = insert(0.5, self.spl, m=2)
splder(spl2, 2) # Should work
assert_raises(ValueError, splder, spl2, 3)
spl2 = insert(0.5, self.spl, m=3)
splder(spl2, 1) # Should work
assert_raises(ValueError, splder, spl2, 2)
spl2 = insert(0.5, self.spl, m=4)
assert_raises(ValueError, splder, spl2, 1)
def test_multidim(self):
# c can have trailing dims
for n in range(3):
t, c, k = self.spl
c2 = np.c_[c, c, c]
c2 = np.dstack((c2, c2))
spl2 = splantider((t, c2, k), n)
spl3 = splder(spl2, n)
assert_allclose(t, spl3[0])
assert_allclose(c2, spl3[1])
assert_equal(k, spl3[2])
class TestSplint:
def test_len_c(self):
n, k = 7, 3
x = np.arange(n)
y = x**3
t, c, k = splrep(x, y, s=0)
# note that len(c) == len(t) == 11 (== len(x) + 2*(k-1))
assert len(t) == len(c) == n + 2*(k-1)
# integrate directly: $\int_0^6 x^3 dx = 6^4 / 4$
res = splint(0, 6, (t, c, k))
assert_allclose(res, 6**4 / 4, atol=1e-15)
# check that the coefficients past len(t) - k - 1 are ignored
c0 = c.copy()
c0[len(t)-k-1:] = np.nan
res0 = splint(0, 6, (t, c0, k))
assert_allclose(res0, 6**4 / 4, atol=1e-15)
# however, all other coefficients *are* used
c0[6] = np.nan
assert np.isnan(splint(0, 6, (t, c0, k)))
# check that the coefficient array can have length `len(t) - k - 1`
c1 = c[:len(t) - k - 1]
res1 = splint(0, 6, (t, c1, k))
assert_allclose(res1, 6**4 / 4, atol=1e-15)
# however shorter c arrays raise. The error from f2py is a
# `dftipack.error`, which is an Exception but not ValueError etc.
with assert_raises(Exception, match=r">=n-k-1"):
splint(0, 1, (np.ones(10), np.ones(5), 3))
class TestBisplrep:
def test_overflow(self):
from numpy.lib.stride_tricks import as_strided
if dfitpack_int.itemsize == 8:
size = 1500000**2
else:
size = 400**2
# Don't allocate a real array, as it's very big, but rely
# on that it's not referenced
x = as_strided(np.zeros(()), shape=(size,))
assert_raises(OverflowError, bisplrep, x, x, x, w=x,
xb=0, xe=1, yb=0, ye=1, s=0)
def test_regression_1310(self):
# Regression test for gh-1310
with np.load(data_file('bug-1310.npz')) as loaded_data:
data = loaded_data['data']
# Shouldn't crash -- the input data triggers work array sizes
# that caused previously some data to not be aligned on
# sizeof(double) boundaries in memory, which made the Fortran
# code to crash when compiled with -O3
bisplrep(data[:,0], data[:,1], data[:,2], kx=3, ky=3, s=0,
full_output=True)
@pytest.mark.skipif(dfitpack_int != np.int64, reason="needs ilp64 fitpack")
def test_ilp64_bisplrep(self):
check_free_memory(28000) # VM size, doesn't actually use the pages
x = np.linspace(0, 1, 400)
y = np.linspace(0, 1, 400)
x, y = np.meshgrid(x, y)
z = np.zeros_like(x)
tck = bisplrep(x, y, z, kx=3, ky=3, s=0)
assert_allclose(bisplev(0.5, 0.5, tck), 0.0)
def test_dblint():
# Basic test to see it runs and gives the correct result on a trivial
# problem. Note that `dblint` is not exposed in the interpolate namespace.
x = np.linspace(0, 1)
y = np.linspace(0, 1)
xx, yy = np.meshgrid(x, y)
rect = RectBivariateSpline(x, y, 4 * xx * yy)
tck = list(rect.tck)
tck.extend(rect.degrees)
assert_almost_equal(dblint(0, 1, 0, 1, tck), 1)
assert_almost_equal(dblint(0, 0.5, 0, 1, tck), 0.25)
assert_almost_equal(dblint(0.5, 1, 0, 1, tck), 0.75)
assert_almost_equal(dblint(-100, 100, -100, 100, tck), 1)
def test_splev_der_k():
# regression test for gh-2188: splev(x, tck, der=k) gives garbage or crashes
# for x outside of knot range
# test case from gh-2188
tck = (np.array([0., 0., 2.5, 2.5]),
np.array([-1.56679978, 2.43995873, 0., 0.]),
1)
t, c, k = tck
x = np.array([-3, 0, 2.5, 3])
# an explicit form of the linear spline
assert_allclose(splev(x, tck), c[0] + (c[1] - c[0]) * x/t[2])
assert_allclose(splev(x, tck, 1), (c[1]-c[0]) / t[2])
# now check a random spline vs splder
np.random.seed(1234)
x = np.sort(np.random.random(30))
y = np.random.random(30)
t, c, k = splrep(x, y)
x = [t[0] - 1., t[-1] + 1.]
tck2 = splder((t, c, k), k)
assert_allclose(splev(x, (t, c, k), k), splev(x, tck2))
def test_splprep_segfault():
# regression test for gh-3847: splprep segfaults if knots are specified
# for task=-1
t = np.arange(0, 1.1, 0.1)
x = np.sin(2*np.pi*t)
y = np.cos(2*np.pi*t)
tck, u = splprep([x, y], s=0)
np.arange(0, 1.01, 0.01)
uknots = tck[0] # using the knots from the previous fitting
tck, u = splprep([x, y], task=-1, t=uknots) # here is the crash
def test_bisplev_integer_overflow():
np.random.seed(1)
x = np.linspace(0, 1, 11)
y = x
z = np.random.randn(11, 11).ravel()
kx = 1
ky = 1
nx, tx, ny, ty, c, fp, ier = regrid_smth(
x, y, z, None, None, None, None, kx=kx, ky=ky, s=0.0)
tck = (tx[:nx], ty[:ny], c[:(nx - kx - 1) * (ny - ky - 1)], kx, ky)
xp = np.zeros([2621440])
yp = np.zeros([2621440])
assert_raises((RuntimeError, MemoryError), bisplev, xp, yp, tck)
@pytest.mark.xslow
def test_gh_1766():
# this should fail gracefully instead of segfaulting (int overflow)
size = 22
kx, ky = 3, 3
def f2(x, y):
return np.sin(x+y)
x = np.linspace(0, 10, size)
y = np.linspace(50, 700, size)
xy = makepairs(x, y)
tck = bisplrep(xy[0], xy[1], f2(xy[0], xy[1]), s=0, kx=kx, ky=ky)
# the size value here can either segfault
# or produce a MemoryError on main
tx_ty_size = 500000
tck[0] = np.arange(tx_ty_size)
tck[1] = np.arange(tx_ty_size) * 4
tt_0 = np.arange(50)
tt_1 = np.arange(50) * 3
with pytest.raises(MemoryError):
bisplev(tt_0, tt_1, tck, 1, 1)
def test_spalde_scalar_input():
# Ticket #629
x = np.linspace(0, 10)
y = x**3
tck = splrep(x, y, k=3, t=[5])
res = spalde(np.float64(1), tck)
des = np.array([1., 3., 6., 6.])
assert_almost_equal(res, des)
def test_spalde_nc():
# regression test for https://github.com/scipy/scipy/issues/19002
# here len(t) = 29 and len(c) = 25 (== len(t) - k - 1)
x = np.asarray([-10., -9., -8., -7., -6., -5., -4., -3., -2.5, -2., -1.5,
-1., -0.5, 0., 0.5, 1., 1.5, 2., 2.5, 3., 4., 5., 6.],
dtype="float")
t = [-10.0, -10.0, -10.0, -10.0, -9.0, -8.0, -7.0, -6.0, -5.0, -4.0, -3.0,
-2.5, -2.0, -1.5, -1.0, -0.5, 0.0, 0.5, 1.0, 1.5, 2.0, 2.5, 3.0, 4.0,
5.0, 6.0, 6.0, 6.0, 6.0]
c = np.asarray([1., 0., 0., 0., 0., 0., 0., 0., 0., 0., 0., 0., 0., 0., 0.,
0., 0., 0., 0., 0., 0., 0., 0., 0., 0.])
k = 3
res = spalde(x, (t, c, k))
res_splev = np.asarray([splev(x, (t, c, k), nu) for nu in range(4)])
assert_allclose(res, res_splev.T, atol=1e-15)