Viewing file:  test_polynomial.py (3.48 KB) -rw-r--r--
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"""
>>> import numpy.core as nx
>>> from numpy.lib.polynomial import poly1d, polydiv
>>> p = poly1d([1.,2,3])
>>> p
poly1d([ 1., 2., 3.])
>>> print p
2
1 x + 2 x + 3
>>> q = poly1d([3.,2,1])
>>> q
poly1d([ 3., 2., 1.])
>>> print q
2
3 x + 2 x + 1
>>> print poly1d([1.89999+2j, -3j, -5.12345678, 2+1j])
3 2
(1.9 + 2j) x - 3j x - 5.123 x + (2 + 1j)
>>> print poly1d([100e-90, 1.234567e-9j+3, -1234.999e8])
2
1e-88 x + (3 + 1.235e-09j) x - 1.235e+11
>>> print poly1d([-3, -2, -1])
2
-3 x - 2 x - 1
>>> p(0)
3.0
>>> p(5)
38.0
>>> q(0)
1.0
>>> q(5)
86.0
>>> p * q
poly1d([ 3., 8., 14., 8., 3.])
>>> p / q
(poly1d([ 0.33333333]), poly1d([ 1.33333333, 2.66666667]))
>>> p + q
poly1d([ 4., 4., 4.])
>>> p - q
poly1d([-2., 0., 2.])
>>> p ** 4
poly1d([ 1., 8., 36., 104., 214., 312., 324., 216., 81.])
>>> p(q)
poly1d([ 9., 12., 16., 8., 6.])
>>> q(p)
poly1d([ 3., 12., 32., 40., 34.])
>>> nx.asarray(p)
array([ 1., 2., 3.])
>>> len(p)
2
>>> p[0], p[1], p[2], p[3]
(3.0, 2.0, 1.0, 0)
>>> p.integ()
poly1d([ 0.33333333, 1. , 3. , 0. ])
>>> p.integ(1)
poly1d([ 0.33333333, 1. , 3. , 0. ])
>>> p.integ(5)
poly1d([ 0.00039683, 0.00277778, 0.025 , 0. , 0. ,
0. , 0. , 0. ])
>>> p.deriv()
poly1d([ 2., 2.])
>>> p.deriv(2)
poly1d([ 2.])
>>> q = poly1d([1.,2,3], variable='y')
>>> print q
2
1 y + 2 y + 3
>>> q = poly1d([1.,2,3], variable='lambda')
>>> print q
2
1 lambda + 2 lambda + 3
>>> polydiv(poly1d([1,0,-1]), poly1d([1,1]))
(poly1d([ 1., -1.]), poly1d([ 0.]))
"""
from numpy.testing import *
import numpy as np
class TestDocs(TestCase):
def test_doctests(self):
return rundocs()
def test_roots(self):
assert_array_equal(np.roots([1,0,0]), [0,0])
def test_str_leading_zeros(self):
p = np.poly1d([4,3,2,1])
p[3] = 0
assert_equal(str(p),
" 2\n"
"3 x + 2 x + 1")
p = np.poly1d([1,2])
p[0] = 0
p[1] = 0
assert_equal(str(p), " \n0")
def test_polyfit(self) :
c = np.array([3., 2., 1.])
x = np.linspace(0,2,5)
y = np.polyval(c,x)
# check 1D case
assert_almost_equal(c, np.polyfit(x,y,2))
# check 2D (n,1) case
y = y[:,np.newaxis]
c = c[:,np.newaxis]
assert_almost_equal(c, np.polyfit(x,y,2))
# check 2D (n,2) case
yy = np.concatenate((y,y), axis=1)
cc = np.concatenate((c,c), axis=1)
assert_almost_equal(cc, np.polyfit(x,yy,2))
def test_objects(self):
from decimal import Decimal
p = np.poly1d([Decimal('4.0'), Decimal('3.0'), Decimal('2.0')])
p2 = p * Decimal('1.333333333333333')
assert p2[1] == Decimal("3.9999999999999990")
p2 = p.deriv()
assert p2[1] == Decimal('8.0')
p2 = p.integ()
assert p2[3] == Decimal("1.333333333333333333333333333")
assert p2[2] == Decimal('1.5')
assert np.issubdtype(p2.coeffs.dtype, np.object_)
def test_complex(self):
p = np.poly1d([3j, 2j, 1j])
p2 = p.integ()
assert (p2.coeffs == [1j,1j,1j,0]).all()
p2 = p.deriv()
assert (p2.coeffs == [6j,2j]).all()
def test_integ_coeffs(self):
p = np.poly1d([3,2,1])
p2 = p.integ(3, k=[9,7,6])
assert (p2.coeffs == [1/4./5.,1/3./4.,1/2./3.,9/1./2.,7,6]).all()
if __name__ == "__main__":
run_module_suite()
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