PyDDM.ISF_and_DDMmatrix_theoretical_models.dTheoryDoubleExp_DDM
PyDDM.ISF_and_DDMmatrix_theoretical_models.dTheoryDoubleExp_DDM¶
-
dTheoryDoubleExp_DDM(lagtime, amp, bg, f, t1, s1, t2, s2)¶ Theoretical model for the DDM matrix with two exponential terms
- Parameters
lagtime (float) – Time lag
amp (float) – Amplitude
bg (float) – Background
f (float) – Fraction with relaxation time t1, between 0-1
t1 (float) – Relaxation time 1
s1 (float) – Stretching exponent 1
t2 (float) – Relaxation time 2
s2 (float) – Stretching exponent 2
- Returns
ddm_matrix (float)- DDM matrix (image structure function)
\[\begin{split}f(q, \Delta t) = f \times e^{\left( \frac{-\Delta t}{\tau 1}\right)^{s1}} + (1-f) \times e^{\left( \frac{-\Delta t}{\tau 2}\right)^{s2}} \\ D(q, \Delta t) = A \times (1-f(q, \Delta t)) + B\end{split}\]