def test_dstrainfit(self):
#create some fake strains
d0=2.34
e1=0.002
e2=-0.0012
e12=0.0008
#the azimuthal angle
phi = np.linspace(-np.pi/2,np.pi/2,23)
#distort the lattice as function of phi
edata = d0 + d0*(e1*np.cos(phi)**2 + e2*np.sin(phi)**2 + e12*np.sin(2*phi))
edata += np.random.uniform(-0.00002,0.00002,edata.size)
edata = unumpy.uarray((edata,np.sqrt(edata)))
#fit
result = strain.strain_from_d(edata,phi,d0)
#check the results
self.assertAlmostEqual(e1,result['strain_x'].nominal_value,4)
self.assertAlmostEqual(e2,result['strain_y'].nominal_value,4)
self.assertAlmostEqual(e12,result['strain_xy'].nominal_value,4)
def test_dstrain_2calc(self):
#create some fake strains
d0=2.34
e1=0.002
e2=-0.0012
e12=0.000
#the azimuthal angle
phi = np.array([0,np.pi/2])
edata = d0 + d0*(e1*np.cos(phi)**2 + e2*np.sin(phi)**2 + e12*np.sin(2*phi))
edata += np.random.uniform(-0.00002,0.00002,edata.size)
edata = unumpy.uarray((edata,np.sqrt(edata)))
#fit
result = strain.strain_from_d(edata,phi,d0)
#check the results
self.assertAlmostEqual(e1,result['strain_x'].nominal_value,4)
self.assertAlmostEqual(e2,result['strain_y'].nominal_value,4)
self.assertAlmostEqual(0,result['strain_xy'].nominal_value,4)
#check this fails if too many phi
badphi = np.array([0.1,np.pi/3])
self.assertRaises(ValueError,strain.strain_from_d,edata,badphi,d0)