def test_q0_fit(self):
q0 = 2.685
ex,ey,exy = 0.002,-0.002,-0.002
#the azimuthal angle in radians
phi = np.linspace(-np.pi/2,np.pi/2,23) #23 detectors over 180 deg
#create some fake peak positions
q = q0 - q0*(ex*np.cos(phi)**2 + ey*np.sin(phi)**2 + exy*np.sin(2*phi))
#add some noise
q += np.random.uniform(-0.00002,0.00002,q.size)
#data/error in uncertainties.unumpy array (poisson statistics)
q = unumpy.uarray((q,np.sqrt(q)))
result = strain.strain_from_q(q,phi)
#check the results
self.assertAlmostEqual(q0,result['q0'].nominal_value,4)
def calcstrain(source,phi,Q0=None,allow_shear=True):
if len(phi) > 2:
take = np.ones(len(phi)).astype(bool)
take[5] = take[8] = False
else:
take=np.ones(2).astype(bool)
for fit,result,info in source:
info['azimuth'] = phi[take]
for key,subresult in result.iteritems():
if Q0 is not None: q0=Q0[key]
else: q0=None
s = strain.strain_from_q(subresult['centre'][take],phi[take],q0,allow_shear)
subresult.update(s)
subresult.update(info) #
yield fit,result,info
def test_qstrain_2calc(self):
#create some fake strains
d0=2.34
e1=0.002
e2=-0.0012
e12=0.000
#convert to q
q0 = 2*np.pi/d0
#the azimuthal angle
phi = np.array([0,np.pi/2])
edata = q0 - q0*(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_q(edata,phi,q0)
#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_q,edata,badphi,d0)
