Changes in / [1a3c0c6:5601947] in sasmodels

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• sasmodels/models/spinodal.py (modified) (3 diffs)

sasmodels/models/spinodal.py

@@ -3 +3 @@
 ----------
 
-This model calculates the SAS signal of a phase separating system 
-undergoing spinodal decomposition. The scattering intensity $I(q)$ is calculated 
-as 
+This model calculates the SAS signal of a phase separating solution
+under spinodal decomposition. The scattering intensity $I(q)$ is calculated as
 
 .. math::
     I(q) = I_{max}\frac{(1+\gamma/2)x^2}{\gamma/2+x^{2+\gamma}}+B
 
-where $x=q/q_0$, $q_0$ is the peak position, $I_{max}$ is the intensity 
-at $q_0$ (parameterised as the $scale$ parameter), and $B$ is a flat 
-background. The spinodal wavelength is given by $2\pi/q_0$. 
-
-The exponent $\gamma$ is equal to $d+1$ for off-critical concentration 
-mixtures (smooth interfaces) and $2d$ for critical concentration mixtures 
-(entangled interfaces), where $d$ is the dimensionality (ie, 1, 2, 3) of the 
-system. Thus 2 <= $\gamma$ <= 6. A transition from $\gamma=d+1$ to $\gamma=2d$ 
-is expected near the percolation threshold. 
-
-As this function tends to zero as $q$ tends to zero, in practice it may be 
-necessary to combine it with another function describing the low-angle 
-scattering, or to simply omit the low-angle scattering from the fit.
+where $x=q/q_0$ and $B$ is a flat background. The characteristic structure
+length scales with the correlation peak at $q_0$. The exponent $\gamma$ is
+equal to $d+1$ with d the dimensionality of the off-critical concentration
+mixtures. A transition to $\gamma=2d$ is seen near the percolation threshold
+into the critical concentration regime.
 
 References
@@ -31 +22 @@
 Physica A 123,497 (1984).
 
-Revision History
-----------------
+Authorship and Verification
+----------------------------
 
-* **Author:**  Dirk Honecker **Date:** Oct 7, 2016
-* **Revised:** Steve King    **Date:** Sep 7, 2018
+* **Author:** Dirk Honecker **Date:** Oct 7, 2016
 """
 
@@ -44 +34 @@
 title = "Spinodal decomposition model"
 description = """\
-      I(q) = Imax ((1+gamma/2)x^2)/(gamma/2+x^(2+gamma)) + background
+      I(q) = scale ((1+gamma/2)x^2)/(gamma/2+x^(2+gamma))+background
 
       List of default parameters:
-      
-      Imax = correlation peak intensity at q_0
-      background = incoherent background
-      gamma = exponent (see model documentation)
+      scale = scaling
+      gamma = exponent
+      x = q/q_0
       q_0 = correlation peak position [1/A]
-      x = q/q_0"""
-      
+      background = Incoherent background"""
 category = "shape-independent"