def test_fractional_anisotropy():
"""
Test the calculation of FA
"""
# Test this both with and without numexpr, if you can:
try:
import numexpr
has_numexpr = True
except ImportError:
has_numexpr = False
if has_numexpr:
for tst_numexpr in [False, True]:
ozu.has_numexpr = tst_numexpr
npt.assert_almost_equal(ozu.fractional_anisotropy(1, 0, 0), 1)
npt.assert_almost_equal(ozu.fractional_anisotropy(1, 1, 1), 0)
else:
npt.assert_almost_equal(ozu.fractional_anisotropy(1, 0, 0), 1)
npt.assert_almost_equal(ozu.fractional_anisotropy(1, 1, 1), 0)
def test_fractional_anisotropy():
"""
Test the calculation of FA
"""
# Test this both with and without numexpr, if you can:
try:
import numexpr
has_numexpr = True
except ImportError:
has_numexpr = False
if has_numexpr:
for tst_numexpr in [False,True]:
ozu.has_numexpr = tst_numexpr
npt.assert_almost_equal(ozu.fractional_anisotropy(1,0,0), 1)
npt.assert_almost_equal(ozu.fractional_anisotropy(1,1,1), 0)
else:
npt.assert_almost_equal(ozu.fractional_anisotropy(1,0,0), 1)
npt.assert_almost_equal(ozu.fractional_anisotropy(1,1,1), 0)
def fractional_anisotropy(self):
"""
.. math::
FA = \sqrt{\frac{1}{2}\frac{(\lambda_1-\lambda_2)^2+(\lambda_1-
\lambda_3)^2+(\lambda_2-lambda_3)^2}{\lambda_1^2+
\lambda_2^2+\lambda_3^2} }
"""
out = ozu.nans(self.data.shape[:3])
lambda_1 = self.evals[..., 0][self.mask]
lambda_2 = self.evals[..., 1][self.mask]
lambda_3 = self.evals[..., 2][self.mask]
out[self.mask] = ozu.fractional_anisotropy(lambda_1, lambda_2, lambda_3)
return out
def fractional_anisotropy(self):
"""
.. math::
FA = \sqrt{\frac{1}{2}\frac{(\lambda_1-\lambda_2)^2+(\lambda_1-
\lambda_3)^2+(\lambda_2-lambda_3)^2}{\lambda_1^2+
\lambda_2^2+\lambda_3^2} }
"""
out = ozu.nans(self.data.shape[:3])
lambda_1 = self.evals[..., 0][self.mask]
lambda_2 = self.evals[..., 1][self.mask]
lambda_3 = self.evals[..., 2][self.mask]
out[self.mask] = ozu.fractional_anisotropy(lambda_1, lambda_2,
lambda_3)
return out